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5931 lines
144 KiB
5931 lines
144 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* SLUB: A slab allocator that limits cache line use instead of queuing |
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* objects in per cpu and per node lists. |
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* |
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* The allocator synchronizes using per slab locks or atomic operations |
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* and only uses a centralized lock to manage a pool of partial slabs. |
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* |
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* (C) 2007 SGI, Christoph Lameter |
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* (C) 2011 Linux Foundation, Christoph Lameter |
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*/ |
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|
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#include <linux/mm.h> |
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#include <linux/swap.h> /* struct reclaim_state */ |
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#include <linux/module.h> |
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#include <linux/bit_spinlock.h> |
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#include <linux/interrupt.h> |
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#include <linux/swab.h> |
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#include <linux/bitops.h> |
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#include <linux/slab.h> |
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#include "slab.h" |
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#include <linux/proc_fs.h> |
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#include <linux/seq_file.h> |
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#include <linux/kasan.h> |
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#include <linux/cpu.h> |
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#include <linux/cpuset.h> |
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#include <linux/mempolicy.h> |
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#include <linux/ctype.h> |
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#include <linux/debugobjects.h> |
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#include <linux/kallsyms.h> |
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#include <linux/kfence.h> |
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#include <linux/memory.h> |
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#include <linux/math64.h> |
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#include <linux/fault-inject.h> |
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#include <linux/stacktrace.h> |
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#include <linux/prefetch.h> |
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#include <linux/memcontrol.h> |
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#include <linux/random.h> |
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#include <kunit/test.h> |
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|
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#include <linux/debugfs.h> |
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#include <trace/events/kmem.h> |
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|
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#include "internal.h" |
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|
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/* |
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* Lock order: |
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* 1. slab_mutex (Global Mutex) |
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* 2. node->list_lock |
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* 3. slab_lock(page) (Only on some arches and for debugging) |
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* |
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* slab_mutex |
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* |
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* The role of the slab_mutex is to protect the list of all the slabs |
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* and to synchronize major metadata changes to slab cache structures. |
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* |
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* The slab_lock is only used for debugging and on arches that do not |
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* have the ability to do a cmpxchg_double. It only protects: |
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* A. page->freelist -> List of object free in a page |
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* B. page->inuse -> Number of objects in use |
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* C. page->objects -> Number of objects in page |
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* D. page->frozen -> frozen state |
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* |
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* If a slab is frozen then it is exempt from list management. It is not |
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* on any list except per cpu partial list. The processor that froze the |
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* slab is the one who can perform list operations on the page. Other |
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* processors may put objects onto the freelist but the processor that |
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* froze the slab is the only one that can retrieve the objects from the |
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* page's freelist. |
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* |
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* The list_lock protects the partial and full list on each node and |
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* the partial slab counter. If taken then no new slabs may be added or |
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* removed from the lists nor make the number of partial slabs be modified. |
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* (Note that the total number of slabs is an atomic value that may be |
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* modified without taking the list lock). |
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* |
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* The list_lock is a centralized lock and thus we avoid taking it as |
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* much as possible. As long as SLUB does not have to handle partial |
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* slabs, operations can continue without any centralized lock. F.e. |
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* allocating a long series of objects that fill up slabs does not require |
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* the list lock. |
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* Interrupts are disabled during allocation and deallocation in order to |
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* make the slab allocator safe to use in the context of an irq. In addition |
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* interrupts are disabled to ensure that the processor does not change |
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* while handling per_cpu slabs, due to kernel preemption. |
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* |
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* SLUB assigns one slab for allocation to each processor. |
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* Allocations only occur from these slabs called cpu slabs. |
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* |
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* Slabs with free elements are kept on a partial list and during regular |
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* operations no list for full slabs is used. If an object in a full slab is |
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* freed then the slab will show up again on the partial lists. |
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* We track full slabs for debugging purposes though because otherwise we |
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* cannot scan all objects. |
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* |
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* Slabs are freed when they become empty. Teardown and setup is |
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* minimal so we rely on the page allocators per cpu caches for |
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* fast frees and allocs. |
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* |
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* page->frozen The slab is frozen and exempt from list processing. |
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* This means that the slab is dedicated to a purpose |
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* such as satisfying allocations for a specific |
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* processor. Objects may be freed in the slab while |
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* it is frozen but slab_free will then skip the usual |
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* list operations. It is up to the processor holding |
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* the slab to integrate the slab into the slab lists |
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* when the slab is no longer needed. |
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* |
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* One use of this flag is to mark slabs that are |
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* used for allocations. Then such a slab becomes a cpu |
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* slab. The cpu slab may be equipped with an additional |
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* freelist that allows lockless access to |
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* free objects in addition to the regular freelist |
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* that requires the slab lock. |
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* |
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* SLAB_DEBUG_FLAGS Slab requires special handling due to debug |
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* options set. This moves slab handling out of |
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* the fast path and disables lockless freelists. |
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*/ |
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|
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#ifdef CONFIG_SLUB_DEBUG |
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#ifdef CONFIG_SLUB_DEBUG_ON |
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DEFINE_STATIC_KEY_TRUE(slub_debug_enabled); |
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#else |
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DEFINE_STATIC_KEY_FALSE(slub_debug_enabled); |
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#endif |
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#endif /* CONFIG_SLUB_DEBUG */ |
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|
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static inline bool kmem_cache_debug(struct kmem_cache *s) |
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{ |
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return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS); |
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} |
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void *fixup_red_left(struct kmem_cache *s, void *p) |
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{ |
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if (kmem_cache_debug_flags(s, SLAB_RED_ZONE)) |
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p += s->red_left_pad; |
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return p; |
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} |
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static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) |
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{ |
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#ifdef CONFIG_SLUB_CPU_PARTIAL |
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return !kmem_cache_debug(s); |
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#else |
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return false; |
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#endif |
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} |
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/* |
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* Issues still to be resolved: |
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* |
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* - Support PAGE_ALLOC_DEBUG. Should be easy to do. |
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* |
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* - Variable sizing of the per node arrays |
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*/ |
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|
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/* Enable to log cmpxchg failures */ |
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#undef SLUB_DEBUG_CMPXCHG |
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|
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/* |
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* Minimum number of partial slabs. These will be left on the partial |
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* lists even if they are empty. kmem_cache_shrink may reclaim them. |
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*/ |
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#define MIN_PARTIAL 5 |
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|
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/* |
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* Maximum number of desirable partial slabs. |
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* The existence of more partial slabs makes kmem_cache_shrink |
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* sort the partial list by the number of objects in use. |
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*/ |
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#define MAX_PARTIAL 10 |
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|
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#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \ |
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SLAB_POISON | SLAB_STORE_USER) |
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|
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/* |
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* These debug flags cannot use CMPXCHG because there might be consistency |
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* issues when checking or reading debug information |
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*/ |
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#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \ |
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SLAB_TRACE) |
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/* |
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* Debugging flags that require metadata to be stored in the slab. These get |
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* disabled when slub_debug=O is used and a cache's min order increases with |
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* metadata. |
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*/ |
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#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) |
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|
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#define OO_SHIFT 16 |
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#define OO_MASK ((1 << OO_SHIFT) - 1) |
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#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */ |
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|
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/* Internal SLUB flags */ |
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/* Poison object */ |
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#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U) |
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/* Use cmpxchg_double */ |
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#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U) |
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/* |
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* Tracking user of a slab. |
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*/ |
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#define TRACK_ADDRS_COUNT 16 |
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struct track { |
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unsigned long addr; /* Called from address */ |
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#ifdef CONFIG_STACKTRACE |
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unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */ |
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#endif |
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int cpu; /* Was running on cpu */ |
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int pid; /* Pid context */ |
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unsigned long when; /* When did the operation occur */ |
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}; |
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enum track_item { TRACK_ALLOC, TRACK_FREE }; |
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#ifdef CONFIG_SYSFS |
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static int sysfs_slab_add(struct kmem_cache *); |
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static int sysfs_slab_alias(struct kmem_cache *, const char *); |
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#else |
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static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; } |
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static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) |
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{ return 0; } |
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#endif |
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#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG) |
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static void debugfs_slab_add(struct kmem_cache *); |
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#else |
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static inline void debugfs_slab_add(struct kmem_cache *s) { } |
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#endif |
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static inline void stat(const struct kmem_cache *s, enum stat_item si) |
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{ |
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#ifdef CONFIG_SLUB_STATS |
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/* |
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* The rmw is racy on a preemptible kernel but this is acceptable, so |
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* avoid this_cpu_add()'s irq-disable overhead. |
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*/ |
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raw_cpu_inc(s->cpu_slab->stat[si]); |
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#endif |
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} |
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/* |
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* Tracks for which NUMA nodes we have kmem_cache_nodes allocated. |
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* Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily |
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* differ during memory hotplug/hotremove operations. |
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* Protected by slab_mutex. |
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*/ |
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static nodemask_t slab_nodes; |
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|
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/******************************************************************** |
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* Core slab cache functions |
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*******************************************************************/ |
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|
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/* |
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* Returns freelist pointer (ptr). With hardening, this is obfuscated |
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* with an XOR of the address where the pointer is held and a per-cache |
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* random number. |
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*/ |
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static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr, |
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unsigned long ptr_addr) |
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{ |
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#ifdef CONFIG_SLAB_FREELIST_HARDENED |
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/* |
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* When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged. |
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* Normally, this doesn't cause any issues, as both set_freepointer() |
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* and get_freepointer() are called with a pointer with the same tag. |
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* However, there are some issues with CONFIG_SLUB_DEBUG code. For |
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* example, when __free_slub() iterates over objects in a cache, it |
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* passes untagged pointers to check_object(). check_object() in turns |
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* calls get_freepointer() with an untagged pointer, which causes the |
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* freepointer to be restored incorrectly. |
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*/ |
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return (void *)((unsigned long)ptr ^ s->random ^ |
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swab((unsigned long)kasan_reset_tag((void *)ptr_addr))); |
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#else |
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return ptr; |
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#endif |
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} |
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|
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/* Returns the freelist pointer recorded at location ptr_addr. */ |
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static inline void *freelist_dereference(const struct kmem_cache *s, |
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void *ptr_addr) |
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{ |
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return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr), |
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(unsigned long)ptr_addr); |
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} |
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static inline void *get_freepointer(struct kmem_cache *s, void *object) |
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{ |
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object = kasan_reset_tag(object); |
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return freelist_dereference(s, object + s->offset); |
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} |
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static void prefetch_freepointer(const struct kmem_cache *s, void *object) |
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{ |
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prefetch(object + s->offset); |
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} |
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static inline void *get_freepointer_safe(struct kmem_cache *s, void *object) |
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{ |
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unsigned long freepointer_addr; |
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void *p; |
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if (!debug_pagealloc_enabled_static()) |
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return get_freepointer(s, object); |
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object = kasan_reset_tag(object); |
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freepointer_addr = (unsigned long)object + s->offset; |
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copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p)); |
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return freelist_ptr(s, p, freepointer_addr); |
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} |
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static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) |
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{ |
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unsigned long freeptr_addr = (unsigned long)object + s->offset; |
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#ifdef CONFIG_SLAB_FREELIST_HARDENED |
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BUG_ON(object == fp); /* naive detection of double free or corruption */ |
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#endif |
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freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr); |
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*(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr); |
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} |
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|
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/* Loop over all objects in a slab */ |
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#define for_each_object(__p, __s, __addr, __objects) \ |
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for (__p = fixup_red_left(__s, __addr); \ |
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__p < (__addr) + (__objects) * (__s)->size; \ |
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__p += (__s)->size) |
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static inline unsigned int order_objects(unsigned int order, unsigned int size) |
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{ |
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return ((unsigned int)PAGE_SIZE << order) / size; |
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} |
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static inline struct kmem_cache_order_objects oo_make(unsigned int order, |
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unsigned int size) |
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{ |
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struct kmem_cache_order_objects x = { |
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(order << OO_SHIFT) + order_objects(order, size) |
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}; |
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return x; |
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} |
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static inline unsigned int oo_order(struct kmem_cache_order_objects x) |
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{ |
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return x.x >> OO_SHIFT; |
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} |
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static inline unsigned int oo_objects(struct kmem_cache_order_objects x) |
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{ |
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return x.x & OO_MASK; |
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} |
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/* |
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* Per slab locking using the pagelock |
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*/ |
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static __always_inline void slab_lock(struct page *page) |
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{ |
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VM_BUG_ON_PAGE(PageTail(page), page); |
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bit_spin_lock(PG_locked, &page->flags); |
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} |
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|
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static __always_inline void slab_unlock(struct page *page) |
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{ |
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VM_BUG_ON_PAGE(PageTail(page), page); |
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__bit_spin_unlock(PG_locked, &page->flags); |
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} |
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|
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/* Interrupts must be disabled (for the fallback code to work right) */ |
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static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
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void *freelist_old, unsigned long counters_old, |
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void *freelist_new, unsigned long counters_new, |
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const char *n) |
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{ |
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VM_BUG_ON(!irqs_disabled()); |
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#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
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defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
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if (s->flags & __CMPXCHG_DOUBLE) { |
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if (cmpxchg_double(&page->freelist, &page->counters, |
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freelist_old, counters_old, |
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freelist_new, counters_new)) |
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return true; |
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} else |
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#endif |
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{ |
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slab_lock(page); |
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if (page->freelist == freelist_old && |
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page->counters == counters_old) { |
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page->freelist = freelist_new; |
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page->counters = counters_new; |
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slab_unlock(page); |
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return true; |
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} |
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slab_unlock(page); |
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} |
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cpu_relax(); |
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stat(s, CMPXCHG_DOUBLE_FAIL); |
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|
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#ifdef SLUB_DEBUG_CMPXCHG |
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pr_info("%s %s: cmpxchg double redo ", n, s->name); |
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#endif |
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return false; |
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} |
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static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
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void *freelist_old, unsigned long counters_old, |
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void *freelist_new, unsigned long counters_new, |
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const char *n) |
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{ |
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#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
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defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
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if (s->flags & __CMPXCHG_DOUBLE) { |
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if (cmpxchg_double(&page->freelist, &page->counters, |
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freelist_old, counters_old, |
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freelist_new, counters_new)) |
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return true; |
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} else |
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#endif |
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{ |
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unsigned long flags; |
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|
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local_irq_save(flags); |
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slab_lock(page); |
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if (page->freelist == freelist_old && |
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page->counters == counters_old) { |
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page->freelist = freelist_new; |
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page->counters = counters_new; |
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slab_unlock(page); |
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local_irq_restore(flags); |
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return true; |
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} |
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slab_unlock(page); |
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local_irq_restore(flags); |
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} |
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|
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cpu_relax(); |
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stat(s, CMPXCHG_DOUBLE_FAIL); |
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|
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#ifdef SLUB_DEBUG_CMPXCHG |
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pr_info("%s %s: cmpxchg double redo ", n, s->name); |
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#endif |
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|
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return false; |
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} |
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|
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#ifdef CONFIG_SLUB_DEBUG |
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static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; |
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static DEFINE_SPINLOCK(object_map_lock); |
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|
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#if IS_ENABLED(CONFIG_KUNIT) |
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static bool slab_add_kunit_errors(void) |
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{ |
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struct kunit_resource *resource; |
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|
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if (likely(!current->kunit_test)) |
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return false; |
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|
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resource = kunit_find_named_resource(current->kunit_test, "slab_errors"); |
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if (!resource) |
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return false; |
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|
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(*(int *)resource->data)++; |
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kunit_put_resource(resource); |
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return true; |
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} |
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#else |
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static inline bool slab_add_kunit_errors(void) { return false; } |
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#endif |
|
|
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/* |
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* Determine a map of object in use on a page. |
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* |
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* Node listlock must be held to guarantee that the page does |
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* not vanish from under us. |
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*/ |
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static unsigned long *get_map(struct kmem_cache *s, struct page *page) |
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__acquires(&object_map_lock) |
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{ |
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void *p; |
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void *addr = page_address(page); |
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|
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VM_BUG_ON(!irqs_disabled()); |
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|
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spin_lock(&object_map_lock); |
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|
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bitmap_zero(object_map, page->objects); |
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|
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for (p = page->freelist; p; p = get_freepointer(s, p)) |
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set_bit(__obj_to_index(s, addr, p), object_map); |
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|
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return object_map; |
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} |
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|
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static void put_map(unsigned long *map) __releases(&object_map_lock) |
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{ |
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VM_BUG_ON(map != object_map); |
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spin_unlock(&object_map_lock); |
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} |
|
|
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static inline unsigned int size_from_object(struct kmem_cache *s) |
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{ |
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if (s->flags & SLAB_RED_ZONE) |
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return s->size - s->red_left_pad; |
|
|
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return s->size; |
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} |
|
|
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static inline void *restore_red_left(struct kmem_cache *s, void *p) |
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{ |
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if (s->flags & SLAB_RED_ZONE) |
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p -= s->red_left_pad; |
|
|
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return p; |
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} |
|
|
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/* |
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* Debug settings: |
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*/ |
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#if defined(CONFIG_SLUB_DEBUG_ON) |
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static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS; |
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#else |
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static slab_flags_t slub_debug; |
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#endif |
|
|
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static char *slub_debug_string; |
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static int disable_higher_order_debug; |
|
|
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/* |
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* slub is about to manipulate internal object metadata. This memory lies |
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* outside the range of the allocated object, so accessing it would normally |
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* be reported by kasan as a bounds error. metadata_access_enable() is used |
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* to tell kasan that these accesses are OK. |
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*/ |
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static inline void metadata_access_enable(void) |
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{ |
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kasan_disable_current(); |
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} |
|
|
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static inline void metadata_access_disable(void) |
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{ |
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kasan_enable_current(); |
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} |
|
|
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/* |
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* Object debugging |
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*/ |
|
|
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/* Verify that a pointer has an address that is valid within a slab page */ |
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static inline int check_valid_pointer(struct kmem_cache *s, |
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struct page *page, void *object) |
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{ |
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void *base; |
|
|
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if (!object) |
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return 1; |
|
|
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base = page_address(page); |
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object = kasan_reset_tag(object); |
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object = restore_red_left(s, object); |
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if (object < base || object >= base + page->objects * s->size || |
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(object - base) % s->size) { |
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return 0; |
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} |
|
|
|
return 1; |
|
} |
|
|
|
static void print_section(char *level, char *text, u8 *addr, |
|
unsigned int length) |
|
{ |
|
metadata_access_enable(); |
|
print_hex_dump(level, kasan_reset_tag(text), DUMP_PREFIX_ADDRESS, |
|
16, 1, addr, length, 1); |
|
metadata_access_disable(); |
|
} |
|
|
|
/* |
|
* See comment in calculate_sizes(). |
|
*/ |
|
static inline bool freeptr_outside_object(struct kmem_cache *s) |
|
{ |
|
return s->offset >= s->inuse; |
|
} |
|
|
|
/* |
|
* Return offset of the end of info block which is inuse + free pointer if |
|
* not overlapping with object. |
|
*/ |
|
static inline unsigned int get_info_end(struct kmem_cache *s) |
|
{ |
|
if (freeptr_outside_object(s)) |
|
return s->inuse + sizeof(void *); |
|
else |
|
return s->inuse; |
|
} |
|
|
|
static struct track *get_track(struct kmem_cache *s, void *object, |
|
enum track_item alloc) |
|
{ |
|
struct track *p; |
|
|
|
p = object + get_info_end(s); |
|
|
|
return kasan_reset_tag(p + alloc); |
|
} |
|
|
|
static void set_track(struct kmem_cache *s, void *object, |
|
enum track_item alloc, unsigned long addr) |
|
{ |
|
struct track *p = get_track(s, object, alloc); |
|
|
|
if (addr) { |
|
#ifdef CONFIG_STACKTRACE |
|
unsigned int nr_entries; |
|
|
|
metadata_access_enable(); |
|
nr_entries = stack_trace_save(kasan_reset_tag(p->addrs), |
|
TRACK_ADDRS_COUNT, 3); |
|
metadata_access_disable(); |
|
|
|
if (nr_entries < TRACK_ADDRS_COUNT) |
|
p->addrs[nr_entries] = 0; |
|
#endif |
|
p->addr = addr; |
|
p->cpu = smp_processor_id(); |
|
p->pid = current->pid; |
|
p->when = jiffies; |
|
} else { |
|
memset(p, 0, sizeof(struct track)); |
|
} |
|
} |
|
|
|
static void init_tracking(struct kmem_cache *s, void *object) |
|
{ |
|
if (!(s->flags & SLAB_STORE_USER)) |
|
return; |
|
|
|
set_track(s, object, TRACK_FREE, 0UL); |
|
set_track(s, object, TRACK_ALLOC, 0UL); |
|
} |
|
|
|
static void print_track(const char *s, struct track *t, unsigned long pr_time) |
|
{ |
|
if (!t->addr) |
|
return; |
|
|
|
pr_err("%s in %pS age=%lu cpu=%u pid=%d\n", |
|
s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid); |
|
#ifdef CONFIG_STACKTRACE |
|
{ |
|
int i; |
|
for (i = 0; i < TRACK_ADDRS_COUNT; i++) |
|
if (t->addrs[i]) |
|
pr_err("\t%pS\n", (void *)t->addrs[i]); |
|
else |
|
break; |
|
} |
|
#endif |
|
} |
|
|
|
void print_tracking(struct kmem_cache *s, void *object) |
|
{ |
|
unsigned long pr_time = jiffies; |
|
if (!(s->flags & SLAB_STORE_USER)) |
|
return; |
|
|
|
print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time); |
|
print_track("Freed", get_track(s, object, TRACK_FREE), pr_time); |
|
} |
|
|
|
static void print_page_info(struct page *page) |
|
{ |
|
pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n", |
|
page, page->objects, page->inuse, page->freelist, |
|
page->flags, &page->flags); |
|
|
|
} |
|
|
|
static void slab_bug(struct kmem_cache *s, char *fmt, ...) |
|
{ |
|
struct va_format vaf; |
|
va_list args; |
|
|
|
va_start(args, fmt); |
|
vaf.fmt = fmt; |
|
vaf.va = &args; |
|
pr_err("=============================================================================\n"); |
|
pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf); |
|
pr_err("-----------------------------------------------------------------------------\n\n"); |
|
va_end(args); |
|
} |
|
|
|
__printf(2, 3) |
|
static void slab_fix(struct kmem_cache *s, char *fmt, ...) |
|
{ |
|
struct va_format vaf; |
|
va_list args; |
|
|
|
if (slab_add_kunit_errors()) |
|
return; |
|
|
|
va_start(args, fmt); |
|
vaf.fmt = fmt; |
|
vaf.va = &args; |
|
pr_err("FIX %s: %pV\n", s->name, &vaf); |
|
va_end(args); |
|
} |
|
|
|
static bool freelist_corrupted(struct kmem_cache *s, struct page *page, |
|
void **freelist, void *nextfree) |
|
{ |
|
if ((s->flags & SLAB_CONSISTENCY_CHECKS) && |
|
!check_valid_pointer(s, page, nextfree) && freelist) { |
|
object_err(s, page, *freelist, "Freechain corrupt"); |
|
*freelist = NULL; |
|
slab_fix(s, "Isolate corrupted freechain"); |
|
return true; |
|
} |
|
|
|
return false; |
|
} |
|
|
|
static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) |
|
{ |
|
unsigned int off; /* Offset of last byte */ |
|
u8 *addr = page_address(page); |
|
|
|
print_tracking(s, p); |
|
|
|
print_page_info(page); |
|
|
|
pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n", |
|
p, p - addr, get_freepointer(s, p)); |
|
|
|
if (s->flags & SLAB_RED_ZONE) |
|
print_section(KERN_ERR, "Redzone ", p - s->red_left_pad, |
|
s->red_left_pad); |
|
else if (p > addr + 16) |
|
print_section(KERN_ERR, "Bytes b4 ", p - 16, 16); |
|
|
|
print_section(KERN_ERR, "Object ", p, |
|
min_t(unsigned int, s->object_size, PAGE_SIZE)); |
|
if (s->flags & SLAB_RED_ZONE) |
|
print_section(KERN_ERR, "Redzone ", p + s->object_size, |
|
s->inuse - s->object_size); |
|
|
|
off = get_info_end(s); |
|
|
|
if (s->flags & SLAB_STORE_USER) |
|
off += 2 * sizeof(struct track); |
|
|
|
off += kasan_metadata_size(s); |
|
|
|
if (off != size_from_object(s)) |
|
/* Beginning of the filler is the free pointer */ |
|
print_section(KERN_ERR, "Padding ", p + off, |
|
size_from_object(s) - off); |
|
|
|
dump_stack(); |
|
} |
|
|
|
void object_err(struct kmem_cache *s, struct page *page, |
|
u8 *object, char *reason) |
|
{ |
|
if (slab_add_kunit_errors()) |
|
return; |
|
|
|
slab_bug(s, "%s", reason); |
|
print_trailer(s, page, object); |
|
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
|
} |
|
|
|
static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page, |
|
const char *fmt, ...) |
|
{ |
|
va_list args; |
|
char buf[100]; |
|
|
|
if (slab_add_kunit_errors()) |
|
return; |
|
|
|
va_start(args, fmt); |
|
vsnprintf(buf, sizeof(buf), fmt, args); |
|
va_end(args); |
|
slab_bug(s, "%s", buf); |
|
print_page_info(page); |
|
dump_stack(); |
|
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
|
} |
|
|
|
static void init_object(struct kmem_cache *s, void *object, u8 val) |
|
{ |
|
u8 *p = kasan_reset_tag(object); |
|
|
|
if (s->flags & SLAB_RED_ZONE) |
|
memset(p - s->red_left_pad, val, s->red_left_pad); |
|
|
|
if (s->flags & __OBJECT_POISON) { |
|
memset(p, POISON_FREE, s->object_size - 1); |
|
p[s->object_size - 1] = POISON_END; |
|
} |
|
|
|
if (s->flags & SLAB_RED_ZONE) |
|
memset(p + s->object_size, val, s->inuse - s->object_size); |
|
} |
|
|
|
static void restore_bytes(struct kmem_cache *s, char *message, u8 data, |
|
void *from, void *to) |
|
{ |
|
slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data); |
|
memset(from, data, to - from); |
|
} |
|
|
|
static int check_bytes_and_report(struct kmem_cache *s, struct page *page, |
|
u8 *object, char *what, |
|
u8 *start, unsigned int value, unsigned int bytes) |
|
{ |
|
u8 *fault; |
|
u8 *end; |
|
u8 *addr = page_address(page); |
|
|
|
metadata_access_enable(); |
|
fault = memchr_inv(kasan_reset_tag(start), value, bytes); |
|
metadata_access_disable(); |
|
if (!fault) |
|
return 1; |
|
|
|
end = start + bytes; |
|
while (end > fault && end[-1] == value) |
|
end--; |
|
|
|
if (slab_add_kunit_errors()) |
|
goto skip_bug_print; |
|
|
|
slab_bug(s, "%s overwritten", what); |
|
pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n", |
|
fault, end - 1, fault - addr, |
|
fault[0], value); |
|
print_trailer(s, page, object); |
|
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
|
|
|
skip_bug_print: |
|
restore_bytes(s, what, value, fault, end); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Object layout: |
|
* |
|
* object address |
|
* Bytes of the object to be managed. |
|
* If the freepointer may overlay the object then the free |
|
* pointer is at the middle of the object. |
|
* |
|
* Poisoning uses 0x6b (POISON_FREE) and the last byte is |
|
* 0xa5 (POISON_END) |
|
* |
|
* object + s->object_size |
|
* Padding to reach word boundary. This is also used for Redzoning. |
|
* Padding is extended by another word if Redzoning is enabled and |
|
* object_size == inuse. |
|
* |
|
* We fill with 0xbb (RED_INACTIVE) for inactive objects and with |
|
* 0xcc (RED_ACTIVE) for objects in use. |
|
* |
|
* object + s->inuse |
|
* Meta data starts here. |
|
* |
|
* A. Free pointer (if we cannot overwrite object on free) |
|
* B. Tracking data for SLAB_STORE_USER |
|
* C. Padding to reach required alignment boundary or at minimum |
|
* one word if debugging is on to be able to detect writes |
|
* before the word boundary. |
|
* |
|
* Padding is done using 0x5a (POISON_INUSE) |
|
* |
|
* object + s->size |
|
* Nothing is used beyond s->size. |
|
* |
|
* If slabcaches are merged then the object_size and inuse boundaries are mostly |
|
* ignored. And therefore no slab options that rely on these boundaries |
|
* may be used with merged slabcaches. |
|
*/ |
|
|
|
static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) |
|
{ |
|
unsigned long off = get_info_end(s); /* The end of info */ |
|
|
|
if (s->flags & SLAB_STORE_USER) |
|
/* We also have user information there */ |
|
off += 2 * sizeof(struct track); |
|
|
|
off += kasan_metadata_size(s); |
|
|
|
if (size_from_object(s) == off) |
|
return 1; |
|
|
|
return check_bytes_and_report(s, page, p, "Object padding", |
|
p + off, POISON_INUSE, size_from_object(s) - off); |
|
} |
|
|
|
/* Check the pad bytes at the end of a slab page */ |
|
static int slab_pad_check(struct kmem_cache *s, struct page *page) |
|
{ |
|
u8 *start; |
|
u8 *fault; |
|
u8 *end; |
|
u8 *pad; |
|
int length; |
|
int remainder; |
|
|
|
if (!(s->flags & SLAB_POISON)) |
|
return 1; |
|
|
|
start = page_address(page); |
|
length = page_size(page); |
|
end = start + length; |
|
remainder = length % s->size; |
|
if (!remainder) |
|
return 1; |
|
|
|
pad = end - remainder; |
|
metadata_access_enable(); |
|
fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder); |
|
metadata_access_disable(); |
|
if (!fault) |
|
return 1; |
|
while (end > fault && end[-1] == POISON_INUSE) |
|
end--; |
|
|
|
slab_err(s, page, "Padding overwritten. 0x%p-0x%p @offset=%tu", |
|
fault, end - 1, fault - start); |
|
print_section(KERN_ERR, "Padding ", pad, remainder); |
|
|
|
restore_bytes(s, "slab padding", POISON_INUSE, fault, end); |
|
return 0; |
|
} |
|
|
|
static int check_object(struct kmem_cache *s, struct page *page, |
|
void *object, u8 val) |
|
{ |
|
u8 *p = object; |
|
u8 *endobject = object + s->object_size; |
|
|
|
if (s->flags & SLAB_RED_ZONE) { |
|
if (!check_bytes_and_report(s, page, object, "Left Redzone", |
|
object - s->red_left_pad, val, s->red_left_pad)) |
|
return 0; |
|
|
|
if (!check_bytes_and_report(s, page, object, "Right Redzone", |
|
endobject, val, s->inuse - s->object_size)) |
|
return 0; |
|
} else { |
|
if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) { |
|
check_bytes_and_report(s, page, p, "Alignment padding", |
|
endobject, POISON_INUSE, |
|
s->inuse - s->object_size); |
|
} |
|
} |
|
|
|
if (s->flags & SLAB_POISON) { |
|
if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) && |
|
(!check_bytes_and_report(s, page, p, "Poison", p, |
|
POISON_FREE, s->object_size - 1) || |
|
!check_bytes_and_report(s, page, p, "End Poison", |
|
p + s->object_size - 1, POISON_END, 1))) |
|
return 0; |
|
/* |
|
* check_pad_bytes cleans up on its own. |
|
*/ |
|
check_pad_bytes(s, page, p); |
|
} |
|
|
|
if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE) |
|
/* |
|
* Object and freepointer overlap. Cannot check |
|
* freepointer while object is allocated. |
|
*/ |
|
return 1; |
|
|
|
/* Check free pointer validity */ |
|
if (!check_valid_pointer(s, page, get_freepointer(s, p))) { |
|
object_err(s, page, p, "Freepointer corrupt"); |
|
/* |
|
* No choice but to zap it and thus lose the remainder |
|
* of the free objects in this slab. May cause |
|
* another error because the object count is now wrong. |
|
*/ |
|
set_freepointer(s, p, NULL); |
|
return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
static int check_slab(struct kmem_cache *s, struct page *page) |
|
{ |
|
int maxobj; |
|
|
|
VM_BUG_ON(!irqs_disabled()); |
|
|
|
if (!PageSlab(page)) { |
|
slab_err(s, page, "Not a valid slab page"); |
|
return 0; |
|
} |
|
|
|
maxobj = order_objects(compound_order(page), s->size); |
|
if (page->objects > maxobj) { |
|
slab_err(s, page, "objects %u > max %u", |
|
page->objects, maxobj); |
|
return 0; |
|
} |
|
if (page->inuse > page->objects) { |
|
slab_err(s, page, "inuse %u > max %u", |
|
page->inuse, page->objects); |
|
return 0; |
|
} |
|
/* Slab_pad_check fixes things up after itself */ |
|
slab_pad_check(s, page); |
|
return 1; |
|
} |
|
|
|
/* |
|
* Determine if a certain object on a page is on the freelist. Must hold the |
|
* slab lock to guarantee that the chains are in a consistent state. |
|
*/ |
|
static int on_freelist(struct kmem_cache *s, struct page *page, void *search) |
|
{ |
|
int nr = 0; |
|
void *fp; |
|
void *object = NULL; |
|
int max_objects; |
|
|
|
fp = page->freelist; |
|
while (fp && nr <= page->objects) { |
|
if (fp == search) |
|
return 1; |
|
if (!check_valid_pointer(s, page, fp)) { |
|
if (object) { |
|
object_err(s, page, object, |
|
"Freechain corrupt"); |
|
set_freepointer(s, object, NULL); |
|
} else { |
|
slab_err(s, page, "Freepointer corrupt"); |
|
page->freelist = NULL; |
|
page->inuse = page->objects; |
|
slab_fix(s, "Freelist cleared"); |
|
return 0; |
|
} |
|
break; |
|
} |
|
object = fp; |
|
fp = get_freepointer(s, object); |
|
nr++; |
|
} |
|
|
|
max_objects = order_objects(compound_order(page), s->size); |
|
if (max_objects > MAX_OBJS_PER_PAGE) |
|
max_objects = MAX_OBJS_PER_PAGE; |
|
|
|
if (page->objects != max_objects) { |
|
slab_err(s, page, "Wrong number of objects. Found %d but should be %d", |
|
page->objects, max_objects); |
|
page->objects = max_objects; |
|
slab_fix(s, "Number of objects adjusted"); |
|
} |
|
if (page->inuse != page->objects - nr) { |
|
slab_err(s, page, "Wrong object count. Counter is %d but counted were %d", |
|
page->inuse, page->objects - nr); |
|
page->inuse = page->objects - nr; |
|
slab_fix(s, "Object count adjusted"); |
|
} |
|
return search == NULL; |
|
} |
|
|
|
static void trace(struct kmem_cache *s, struct page *page, void *object, |
|
int alloc) |
|
{ |
|
if (s->flags & SLAB_TRACE) { |
|
pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n", |
|
s->name, |
|
alloc ? "alloc" : "free", |
|
object, page->inuse, |
|
page->freelist); |
|
|
|
if (!alloc) |
|
print_section(KERN_INFO, "Object ", (void *)object, |
|
s->object_size); |
|
|
|
dump_stack(); |
|
} |
|
} |
|
|
|
/* |
|
* Tracking of fully allocated slabs for debugging purposes. |
|
*/ |
|
static void add_full(struct kmem_cache *s, |
|
struct kmem_cache_node *n, struct page *page) |
|
{ |
|
if (!(s->flags & SLAB_STORE_USER)) |
|
return; |
|
|
|
lockdep_assert_held(&n->list_lock); |
|
list_add(&page->slab_list, &n->full); |
|
} |
|
|
|
static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page) |
|
{ |
|
if (!(s->flags & SLAB_STORE_USER)) |
|
return; |
|
|
|
lockdep_assert_held(&n->list_lock); |
|
list_del(&page->slab_list); |
|
} |
|
|
|
/* Tracking of the number of slabs for debugging purposes */ |
|
static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
|
{ |
|
struct kmem_cache_node *n = get_node(s, node); |
|
|
|
return atomic_long_read(&n->nr_slabs); |
|
} |
|
|
|
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
|
{ |
|
return atomic_long_read(&n->nr_slabs); |
|
} |
|
|
|
static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) |
|
{ |
|
struct kmem_cache_node *n = get_node(s, node); |
|
|
|
/* |
|
* May be called early in order to allocate a slab for the |
|
* kmem_cache_node structure. Solve the chicken-egg |
|
* dilemma by deferring the increment of the count during |
|
* bootstrap (see early_kmem_cache_node_alloc). |
|
*/ |
|
if (likely(n)) { |
|
atomic_long_inc(&n->nr_slabs); |
|
atomic_long_add(objects, &n->total_objects); |
|
} |
|
} |
|
static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) |
|
{ |
|
struct kmem_cache_node *n = get_node(s, node); |
|
|
|
atomic_long_dec(&n->nr_slabs); |
|
atomic_long_sub(objects, &n->total_objects); |
|
} |
|
|
|
/* Object debug checks for alloc/free paths */ |
|
static void setup_object_debug(struct kmem_cache *s, struct page *page, |
|
void *object) |
|
{ |
|
if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)) |
|
return; |
|
|
|
init_object(s, object, SLUB_RED_INACTIVE); |
|
init_tracking(s, object); |
|
} |
|
|
|
static |
|
void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) |
|
{ |
|
if (!kmem_cache_debug_flags(s, SLAB_POISON)) |
|
return; |
|
|
|
metadata_access_enable(); |
|
memset(kasan_reset_tag(addr), POISON_INUSE, page_size(page)); |
|
metadata_access_disable(); |
|
} |
|
|
|
static inline int alloc_consistency_checks(struct kmem_cache *s, |
|
struct page *page, void *object) |
|
{ |
|
if (!check_slab(s, page)) |
|
return 0; |
|
|
|
if (!check_valid_pointer(s, page, object)) { |
|
object_err(s, page, object, "Freelist Pointer check fails"); |
|
return 0; |
|
} |
|
|
|
if (!check_object(s, page, object, SLUB_RED_INACTIVE)) |
|
return 0; |
|
|
|
return 1; |
|
} |
|
|
|
static noinline int alloc_debug_processing(struct kmem_cache *s, |
|
struct page *page, |
|
void *object, unsigned long addr) |
|
{ |
|
if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
|
if (!alloc_consistency_checks(s, page, object)) |
|
goto bad; |
|
} |
|
|
|
/* Success perform special debug activities for allocs */ |
|
if (s->flags & SLAB_STORE_USER) |
|
set_track(s, object, TRACK_ALLOC, addr); |
|
trace(s, page, object, 1); |
|
init_object(s, object, SLUB_RED_ACTIVE); |
|
return 1; |
|
|
|
bad: |
|
if (PageSlab(page)) { |
|
/* |
|
* If this is a slab page then lets do the best we can |
|
* to avoid issues in the future. Marking all objects |
|
* as used avoids touching the remaining objects. |
|
*/ |
|
slab_fix(s, "Marking all objects used"); |
|
page->inuse = page->objects; |
|
page->freelist = NULL; |
|
} |
|
return 0; |
|
} |
|
|
|
static inline int free_consistency_checks(struct kmem_cache *s, |
|
struct page *page, void *object, unsigned long addr) |
|
{ |
|
if (!check_valid_pointer(s, page, object)) { |
|
slab_err(s, page, "Invalid object pointer 0x%p", object); |
|
return 0; |
|
} |
|
|
|
if (on_freelist(s, page, object)) { |
|
object_err(s, page, object, "Object already free"); |
|
return 0; |
|
} |
|
|
|
if (!check_object(s, page, object, SLUB_RED_ACTIVE)) |
|
return 0; |
|
|
|
if (unlikely(s != page->slab_cache)) { |
|
if (!PageSlab(page)) { |
|
slab_err(s, page, "Attempt to free object(0x%p) outside of slab", |
|
object); |
|
} else if (!page->slab_cache) { |
|
pr_err("SLUB <none>: no slab for object 0x%p.\n", |
|
object); |
|
dump_stack(); |
|
} else |
|
object_err(s, page, object, |
|
"page slab pointer corrupt."); |
|
return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
/* Supports checking bulk free of a constructed freelist */ |
|
static noinline int free_debug_processing( |
|
struct kmem_cache *s, struct page *page, |
|
void *head, void *tail, int bulk_cnt, |
|
unsigned long addr) |
|
{ |
|
struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
|
void *object = head; |
|
int cnt = 0; |
|
unsigned long flags; |
|
int ret = 0; |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
slab_lock(page); |
|
|
|
if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
|
if (!check_slab(s, page)) |
|
goto out; |
|
} |
|
|
|
next_object: |
|
cnt++; |
|
|
|
if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
|
if (!free_consistency_checks(s, page, object, addr)) |
|
goto out; |
|
} |
|
|
|
if (s->flags & SLAB_STORE_USER) |
|
set_track(s, object, TRACK_FREE, addr); |
|
trace(s, page, object, 0); |
|
/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */ |
|
init_object(s, object, SLUB_RED_INACTIVE); |
|
|
|
/* Reached end of constructed freelist yet? */ |
|
if (object != tail) { |
|
object = get_freepointer(s, object); |
|
goto next_object; |
|
} |
|
ret = 1; |
|
|
|
out: |
|
if (cnt != bulk_cnt) |
|
slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n", |
|
bulk_cnt, cnt); |
|
|
|
slab_unlock(page); |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
if (!ret) |
|
slab_fix(s, "Object at 0x%p not freed", object); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Parse a block of slub_debug options. Blocks are delimited by ';' |
|
* |
|
* @str: start of block |
|
* @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified |
|
* @slabs: return start of list of slabs, or NULL when there's no list |
|
* @init: assume this is initial parsing and not per-kmem-create parsing |
|
* |
|
* returns the start of next block if there's any, or NULL |
|
*/ |
|
static char * |
|
parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init) |
|
{ |
|
bool higher_order_disable = false; |
|
|
|
/* Skip any completely empty blocks */ |
|
while (*str && *str == ';') |
|
str++; |
|
|
|
if (*str == ',') { |
|
/* |
|
* No options but restriction on slabs. This means full |
|
* debugging for slabs matching a pattern. |
|
*/ |
|
*flags = DEBUG_DEFAULT_FLAGS; |
|
goto check_slabs; |
|
} |
|
*flags = 0; |
|
|
|
/* Determine which debug features should be switched on */ |
|
for (; *str && *str != ',' && *str != ';'; str++) { |
|
switch (tolower(*str)) { |
|
case '-': |
|
*flags = 0; |
|
break; |
|
case 'f': |
|
*flags |= SLAB_CONSISTENCY_CHECKS; |
|
break; |
|
case 'z': |
|
*flags |= SLAB_RED_ZONE; |
|
break; |
|
case 'p': |
|
*flags |= SLAB_POISON; |
|
break; |
|
case 'u': |
|
*flags |= SLAB_STORE_USER; |
|
break; |
|
case 't': |
|
*flags |= SLAB_TRACE; |
|
break; |
|
case 'a': |
|
*flags |= SLAB_FAILSLAB; |
|
break; |
|
case 'o': |
|
/* |
|
* Avoid enabling debugging on caches if its minimum |
|
* order would increase as a result. |
|
*/ |
|
higher_order_disable = true; |
|
break; |
|
default: |
|
if (init) |
|
pr_err("slub_debug option '%c' unknown. skipped\n", *str); |
|
} |
|
} |
|
check_slabs: |
|
if (*str == ',') |
|
*slabs = ++str; |
|
else |
|
*slabs = NULL; |
|
|
|
/* Skip over the slab list */ |
|
while (*str && *str != ';') |
|
str++; |
|
|
|
/* Skip any completely empty blocks */ |
|
while (*str && *str == ';') |
|
str++; |
|
|
|
if (init && higher_order_disable) |
|
disable_higher_order_debug = 1; |
|
|
|
if (*str) |
|
return str; |
|
else |
|
return NULL; |
|
} |
|
|
|
static int __init setup_slub_debug(char *str) |
|
{ |
|
slab_flags_t flags; |
|
char *saved_str; |
|
char *slab_list; |
|
bool global_slub_debug_changed = false; |
|
bool slab_list_specified = false; |
|
|
|
slub_debug = DEBUG_DEFAULT_FLAGS; |
|
if (*str++ != '=' || !*str) |
|
/* |
|
* No options specified. Switch on full debugging. |
|
*/ |
|
goto out; |
|
|
|
saved_str = str; |
|
while (str) { |
|
str = parse_slub_debug_flags(str, &flags, &slab_list, true); |
|
|
|
if (!slab_list) { |
|
slub_debug = flags; |
|
global_slub_debug_changed = true; |
|
} else { |
|
slab_list_specified = true; |
|
} |
|
} |
|
|
|
/* |
|
* For backwards compatibility, a single list of flags with list of |
|
* slabs means debugging is only enabled for those slabs, so the global |
|
* slub_debug should be 0. We can extended that to multiple lists as |
|
* long as there is no option specifying flags without a slab list. |
|
*/ |
|
if (slab_list_specified) { |
|
if (!global_slub_debug_changed) |
|
slub_debug = 0; |
|
slub_debug_string = saved_str; |
|
} |
|
out: |
|
if (slub_debug != 0 || slub_debug_string) |
|
static_branch_enable(&slub_debug_enabled); |
|
else |
|
static_branch_disable(&slub_debug_enabled); |
|
if ((static_branch_unlikely(&init_on_alloc) || |
|
static_branch_unlikely(&init_on_free)) && |
|
(slub_debug & SLAB_POISON)) |
|
pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n"); |
|
return 1; |
|
} |
|
|
|
__setup("slub_debug", setup_slub_debug); |
|
|
|
/* |
|
* kmem_cache_flags - apply debugging options to the cache |
|
* @object_size: the size of an object without meta data |
|
* @flags: flags to set |
|
* @name: name of the cache |
|
* |
|
* Debug option(s) are applied to @flags. In addition to the debug |
|
* option(s), if a slab name (or multiple) is specified i.e. |
|
* slub_debug=<Debug-Options>,<slab name1>,<slab name2> ... |
|
* then only the select slabs will receive the debug option(s). |
|
*/ |
|
slab_flags_t kmem_cache_flags(unsigned int object_size, |
|
slab_flags_t flags, const char *name) |
|
{ |
|
char *iter; |
|
size_t len; |
|
char *next_block; |
|
slab_flags_t block_flags; |
|
slab_flags_t slub_debug_local = slub_debug; |
|
|
|
/* |
|
* If the slab cache is for debugging (e.g. kmemleak) then |
|
* don't store user (stack trace) information by default, |
|
* but let the user enable it via the command line below. |
|
*/ |
|
if (flags & SLAB_NOLEAKTRACE) |
|
slub_debug_local &= ~SLAB_STORE_USER; |
|
|
|
len = strlen(name); |
|
next_block = slub_debug_string; |
|
/* Go through all blocks of debug options, see if any matches our slab's name */ |
|
while (next_block) { |
|
next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false); |
|
if (!iter) |
|
continue; |
|
/* Found a block that has a slab list, search it */ |
|
while (*iter) { |
|
char *end, *glob; |
|
size_t cmplen; |
|
|
|
end = strchrnul(iter, ','); |
|
if (next_block && next_block < end) |
|
end = next_block - 1; |
|
|
|
glob = strnchr(iter, end - iter, '*'); |
|
if (glob) |
|
cmplen = glob - iter; |
|
else |
|
cmplen = max_t(size_t, len, (end - iter)); |
|
|
|
if (!strncmp(name, iter, cmplen)) { |
|
flags |= block_flags; |
|
return flags; |
|
} |
|
|
|
if (!*end || *end == ';') |
|
break; |
|
iter = end + 1; |
|
} |
|
} |
|
|
|
return flags | slub_debug_local; |
|
} |
|
#else /* !CONFIG_SLUB_DEBUG */ |
|
static inline void setup_object_debug(struct kmem_cache *s, |
|
struct page *page, void *object) {} |
|
static inline |
|
void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {} |
|
|
|
static inline int alloc_debug_processing(struct kmem_cache *s, |
|
struct page *page, void *object, unsigned long addr) { return 0; } |
|
|
|
static inline int free_debug_processing( |
|
struct kmem_cache *s, struct page *page, |
|
void *head, void *tail, int bulk_cnt, |
|
unsigned long addr) { return 0; } |
|
|
|
static inline int slab_pad_check(struct kmem_cache *s, struct page *page) |
|
{ return 1; } |
|
static inline int check_object(struct kmem_cache *s, struct page *page, |
|
void *object, u8 val) { return 1; } |
|
static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, |
|
struct page *page) {} |
|
static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, |
|
struct page *page) {} |
|
slab_flags_t kmem_cache_flags(unsigned int object_size, |
|
slab_flags_t flags, const char *name) |
|
{ |
|
return flags; |
|
} |
|
#define slub_debug 0 |
|
|
|
#define disable_higher_order_debug 0 |
|
|
|
static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
|
{ return 0; } |
|
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
|
{ return 0; } |
|
static inline void inc_slabs_node(struct kmem_cache *s, int node, |
|
int objects) {} |
|
static inline void dec_slabs_node(struct kmem_cache *s, int node, |
|
int objects) {} |
|
|
|
static bool freelist_corrupted(struct kmem_cache *s, struct page *page, |
|
void **freelist, void *nextfree) |
|
{ |
|
return false; |
|
} |
|
#endif /* CONFIG_SLUB_DEBUG */ |
|
|
|
/* |
|
* Hooks for other subsystems that check memory allocations. In a typical |
|
* production configuration these hooks all should produce no code at all. |
|
*/ |
|
static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags) |
|
{ |
|
ptr = kasan_kmalloc_large(ptr, size, flags); |
|
/* As ptr might get tagged, call kmemleak hook after KASAN. */ |
|
kmemleak_alloc(ptr, size, 1, flags); |
|
return ptr; |
|
} |
|
|
|
static __always_inline void kfree_hook(void *x) |
|
{ |
|
kmemleak_free(x); |
|
kasan_kfree_large(x); |
|
} |
|
|
|
static __always_inline bool slab_free_hook(struct kmem_cache *s, |
|
void *x, bool init) |
|
{ |
|
kmemleak_free_recursive(x, s->flags); |
|
|
|
/* |
|
* Trouble is that we may no longer disable interrupts in the fast path |
|
* So in order to make the debug calls that expect irqs to be |
|
* disabled we need to disable interrupts temporarily. |
|
*/ |
|
#ifdef CONFIG_LOCKDEP |
|
{ |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
debug_check_no_locks_freed(x, s->object_size); |
|
local_irq_restore(flags); |
|
} |
|
#endif |
|
if (!(s->flags & SLAB_DEBUG_OBJECTS)) |
|
debug_check_no_obj_freed(x, s->object_size); |
|
|
|
/* Use KCSAN to help debug racy use-after-free. */ |
|
if (!(s->flags & SLAB_TYPESAFE_BY_RCU)) |
|
__kcsan_check_access(x, s->object_size, |
|
KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT); |
|
|
|
/* |
|
* As memory initialization might be integrated into KASAN, |
|
* kasan_slab_free and initialization memset's must be |
|
* kept together to avoid discrepancies in behavior. |
|
* |
|
* The initialization memset's clear the object and the metadata, |
|
* but don't touch the SLAB redzone. |
|
*/ |
|
if (init) { |
|
int rsize; |
|
|
|
if (!kasan_has_integrated_init()) |
|
memset(kasan_reset_tag(x), 0, s->object_size); |
|
rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0; |
|
memset((char *)kasan_reset_tag(x) + s->inuse, 0, |
|
s->size - s->inuse - rsize); |
|
} |
|
/* KASAN might put x into memory quarantine, delaying its reuse. */ |
|
return kasan_slab_free(s, x, init); |
|
} |
|
|
|
static inline bool slab_free_freelist_hook(struct kmem_cache *s, |
|
void **head, void **tail) |
|
{ |
|
|
|
void *object; |
|
void *next = *head; |
|
void *old_tail = *tail ? *tail : *head; |
|
|
|
if (is_kfence_address(next)) { |
|
slab_free_hook(s, next, false); |
|
return true; |
|
} |
|
|
|
/* Head and tail of the reconstructed freelist */ |
|
*head = NULL; |
|
*tail = NULL; |
|
|
|
do { |
|
object = next; |
|
next = get_freepointer(s, object); |
|
|
|
/* If object's reuse doesn't have to be delayed */ |
|
if (!slab_free_hook(s, object, slab_want_init_on_free(s))) { |
|
/* Move object to the new freelist */ |
|
set_freepointer(s, object, *head); |
|
*head = object; |
|
if (!*tail) |
|
*tail = object; |
|
} |
|
} while (object != old_tail); |
|
|
|
if (*head == *tail) |
|
*tail = NULL; |
|
|
|
return *head != NULL; |
|
} |
|
|
|
static void *setup_object(struct kmem_cache *s, struct page *page, |
|
void *object) |
|
{ |
|
setup_object_debug(s, page, object); |
|
object = kasan_init_slab_obj(s, object); |
|
if (unlikely(s->ctor)) { |
|
kasan_unpoison_object_data(s, object); |
|
s->ctor(object); |
|
kasan_poison_object_data(s, object); |
|
} |
|
return object; |
|
} |
|
|
|
/* |
|
* Slab allocation and freeing |
|
*/ |
|
static inline struct page *alloc_slab_page(struct kmem_cache *s, |
|
gfp_t flags, int node, struct kmem_cache_order_objects oo) |
|
{ |
|
struct page *page; |
|
unsigned int order = oo_order(oo); |
|
|
|
if (node == NUMA_NO_NODE) |
|
page = alloc_pages(flags, order); |
|
else |
|
page = __alloc_pages_node(node, flags, order); |
|
|
|
return page; |
|
} |
|
|
|
#ifdef CONFIG_SLAB_FREELIST_RANDOM |
|
/* Pre-initialize the random sequence cache */ |
|
static int init_cache_random_seq(struct kmem_cache *s) |
|
{ |
|
unsigned int count = oo_objects(s->oo); |
|
int err; |
|
|
|
/* Bailout if already initialised */ |
|
if (s->random_seq) |
|
return 0; |
|
|
|
err = cache_random_seq_create(s, count, GFP_KERNEL); |
|
if (err) { |
|
pr_err("SLUB: Unable to initialize free list for %s\n", |
|
s->name); |
|
return err; |
|
} |
|
|
|
/* Transform to an offset on the set of pages */ |
|
if (s->random_seq) { |
|
unsigned int i; |
|
|
|
for (i = 0; i < count; i++) |
|
s->random_seq[i] *= s->size; |
|
} |
|
return 0; |
|
} |
|
|
|
/* Initialize each random sequence freelist per cache */ |
|
static void __init init_freelist_randomization(void) |
|
{ |
|
struct kmem_cache *s; |
|
|
|
mutex_lock(&slab_mutex); |
|
|
|
list_for_each_entry(s, &slab_caches, list) |
|
init_cache_random_seq(s); |
|
|
|
mutex_unlock(&slab_mutex); |
|
} |
|
|
|
/* Get the next entry on the pre-computed freelist randomized */ |
|
static void *next_freelist_entry(struct kmem_cache *s, struct page *page, |
|
unsigned long *pos, void *start, |
|
unsigned long page_limit, |
|
unsigned long freelist_count) |
|
{ |
|
unsigned int idx; |
|
|
|
/* |
|
* If the target page allocation failed, the number of objects on the |
|
* page might be smaller than the usual size defined by the cache. |
|
*/ |
|
do { |
|
idx = s->random_seq[*pos]; |
|
*pos += 1; |
|
if (*pos >= freelist_count) |
|
*pos = 0; |
|
} while (unlikely(idx >= page_limit)); |
|
|
|
return (char *)start + idx; |
|
} |
|
|
|
/* Shuffle the single linked freelist based on a random pre-computed sequence */ |
|
static bool shuffle_freelist(struct kmem_cache *s, struct page *page) |
|
{ |
|
void *start; |
|
void *cur; |
|
void *next; |
|
unsigned long idx, pos, page_limit, freelist_count; |
|
|
|
if (page->objects < 2 || !s->random_seq) |
|
return false; |
|
|
|
freelist_count = oo_objects(s->oo); |
|
pos = get_random_int() % freelist_count; |
|
|
|
page_limit = page->objects * s->size; |
|
start = fixup_red_left(s, page_address(page)); |
|
|
|
/* First entry is used as the base of the freelist */ |
|
cur = next_freelist_entry(s, page, &pos, start, page_limit, |
|
freelist_count); |
|
cur = setup_object(s, page, cur); |
|
page->freelist = cur; |
|
|
|
for (idx = 1; idx < page->objects; idx++) { |
|
next = next_freelist_entry(s, page, &pos, start, page_limit, |
|
freelist_count); |
|
next = setup_object(s, page, next); |
|
set_freepointer(s, cur, next); |
|
cur = next; |
|
} |
|
set_freepointer(s, cur, NULL); |
|
|
|
return true; |
|
} |
|
#else |
|
static inline int init_cache_random_seq(struct kmem_cache *s) |
|
{ |
|
return 0; |
|
} |
|
static inline void init_freelist_randomization(void) { } |
|
static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page) |
|
{ |
|
return false; |
|
} |
|
#endif /* CONFIG_SLAB_FREELIST_RANDOM */ |
|
|
|
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) |
|
{ |
|
struct page *page; |
|
struct kmem_cache_order_objects oo = s->oo; |
|
gfp_t alloc_gfp; |
|
void *start, *p, *next; |
|
int idx; |
|
bool shuffle; |
|
|
|
flags &= gfp_allowed_mask; |
|
|
|
if (gfpflags_allow_blocking(flags)) |
|
local_irq_enable(); |
|
|
|
flags |= s->allocflags; |
|
|
|
/* |
|
* Let the initial higher-order allocation fail under memory pressure |
|
* so we fall-back to the minimum order allocation. |
|
*/ |
|
alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; |
|
if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min)) |
|
alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL); |
|
|
|
page = alloc_slab_page(s, alloc_gfp, node, oo); |
|
if (unlikely(!page)) { |
|
oo = s->min; |
|
alloc_gfp = flags; |
|
/* |
|
* Allocation may have failed due to fragmentation. |
|
* Try a lower order alloc if possible |
|
*/ |
|
page = alloc_slab_page(s, alloc_gfp, node, oo); |
|
if (unlikely(!page)) |
|
goto out; |
|
stat(s, ORDER_FALLBACK); |
|
} |
|
|
|
page->objects = oo_objects(oo); |
|
|
|
account_slab_page(page, oo_order(oo), s, flags); |
|
|
|
page->slab_cache = s; |
|
__SetPageSlab(page); |
|
if (page_is_pfmemalloc(page)) |
|
SetPageSlabPfmemalloc(page); |
|
|
|
kasan_poison_slab(page); |
|
|
|
start = page_address(page); |
|
|
|
setup_page_debug(s, page, start); |
|
|
|
shuffle = shuffle_freelist(s, page); |
|
|
|
if (!shuffle) { |
|
start = fixup_red_left(s, start); |
|
start = setup_object(s, page, start); |
|
page->freelist = start; |
|
for (idx = 0, p = start; idx < page->objects - 1; idx++) { |
|
next = p + s->size; |
|
next = setup_object(s, page, next); |
|
set_freepointer(s, p, next); |
|
p = next; |
|
} |
|
set_freepointer(s, p, NULL); |
|
} |
|
|
|
page->inuse = page->objects; |
|
page->frozen = 1; |
|
|
|
out: |
|
if (gfpflags_allow_blocking(flags)) |
|
local_irq_disable(); |
|
if (!page) |
|
return NULL; |
|
|
|
inc_slabs_node(s, page_to_nid(page), page->objects); |
|
|
|
return page; |
|
} |
|
|
|
static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) |
|
{ |
|
if (unlikely(flags & GFP_SLAB_BUG_MASK)) |
|
flags = kmalloc_fix_flags(flags); |
|
|
|
return allocate_slab(s, |
|
flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); |
|
} |
|
|
|
static void __free_slab(struct kmem_cache *s, struct page *page) |
|
{ |
|
int order = compound_order(page); |
|
int pages = 1 << order; |
|
|
|
if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) { |
|
void *p; |
|
|
|
slab_pad_check(s, page); |
|
for_each_object(p, s, page_address(page), |
|
page->objects) |
|
check_object(s, page, p, SLUB_RED_INACTIVE); |
|
} |
|
|
|
__ClearPageSlabPfmemalloc(page); |
|
__ClearPageSlab(page); |
|
/* In union with page->mapping where page allocator expects NULL */ |
|
page->slab_cache = NULL; |
|
if (current->reclaim_state) |
|
current->reclaim_state->reclaimed_slab += pages; |
|
unaccount_slab_page(page, order, s); |
|
__free_pages(page, order); |
|
} |
|
|
|
static void rcu_free_slab(struct rcu_head *h) |
|
{ |
|
struct page *page = container_of(h, struct page, rcu_head); |
|
|
|
__free_slab(page->slab_cache, page); |
|
} |
|
|
|
static void free_slab(struct kmem_cache *s, struct page *page) |
|
{ |
|
if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) { |
|
call_rcu(&page->rcu_head, rcu_free_slab); |
|
} else |
|
__free_slab(s, page); |
|
} |
|
|
|
static void discard_slab(struct kmem_cache *s, struct page *page) |
|
{ |
|
dec_slabs_node(s, page_to_nid(page), page->objects); |
|
free_slab(s, page); |
|
} |
|
|
|
/* |
|
* Management of partially allocated slabs. |
|
*/ |
|
static inline void |
|
__add_partial(struct kmem_cache_node *n, struct page *page, int tail) |
|
{ |
|
n->nr_partial++; |
|
if (tail == DEACTIVATE_TO_TAIL) |
|
list_add_tail(&page->slab_list, &n->partial); |
|
else |
|
list_add(&page->slab_list, &n->partial); |
|
} |
|
|
|
static inline void add_partial(struct kmem_cache_node *n, |
|
struct page *page, int tail) |
|
{ |
|
lockdep_assert_held(&n->list_lock); |
|
__add_partial(n, page, tail); |
|
} |
|
|
|
static inline void remove_partial(struct kmem_cache_node *n, |
|
struct page *page) |
|
{ |
|
lockdep_assert_held(&n->list_lock); |
|
list_del(&page->slab_list); |
|
n->nr_partial--; |
|
} |
|
|
|
/* |
|
* Remove slab from the partial list, freeze it and |
|
* return the pointer to the freelist. |
|
* |
|
* Returns a list of objects or NULL if it fails. |
|
*/ |
|
static inline void *acquire_slab(struct kmem_cache *s, |
|
struct kmem_cache_node *n, struct page *page, |
|
int mode, int *objects) |
|
{ |
|
void *freelist; |
|
unsigned long counters; |
|
struct page new; |
|
|
|
lockdep_assert_held(&n->list_lock); |
|
|
|
/* |
|
* Zap the freelist and set the frozen bit. |
|
* The old freelist is the list of objects for the |
|
* per cpu allocation list. |
|
*/ |
|
freelist = page->freelist; |
|
counters = page->counters; |
|
new.counters = counters; |
|
*objects = new.objects - new.inuse; |
|
if (mode) { |
|
new.inuse = page->objects; |
|
new.freelist = NULL; |
|
} else { |
|
new.freelist = freelist; |
|
} |
|
|
|
VM_BUG_ON(new.frozen); |
|
new.frozen = 1; |
|
|
|
if (!__cmpxchg_double_slab(s, page, |
|
freelist, counters, |
|
new.freelist, new.counters, |
|
"acquire_slab")) |
|
return NULL; |
|
|
|
remove_partial(n, page); |
|
WARN_ON(!freelist); |
|
return freelist; |
|
} |
|
|
|
static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain); |
|
static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags); |
|
|
|
/* |
|
* Try to allocate a partial slab from a specific node. |
|
*/ |
|
static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, |
|
struct kmem_cache_cpu *c, gfp_t flags) |
|
{ |
|
struct page *page, *page2; |
|
void *object = NULL; |
|
unsigned int available = 0; |
|
int objects; |
|
|
|
/* |
|
* Racy check. If we mistakenly see no partial slabs then we |
|
* just allocate an empty slab. If we mistakenly try to get a |
|
* partial slab and there is none available then get_partial() |
|
* will return NULL. |
|
*/ |
|
if (!n || !n->nr_partial) |
|
return NULL; |
|
|
|
spin_lock(&n->list_lock); |
|
list_for_each_entry_safe(page, page2, &n->partial, slab_list) { |
|
void *t; |
|
|
|
if (!pfmemalloc_match(page, flags)) |
|
continue; |
|
|
|
t = acquire_slab(s, n, page, object == NULL, &objects); |
|
if (!t) |
|
break; |
|
|
|
available += objects; |
|
if (!object) { |
|
c->page = page; |
|
stat(s, ALLOC_FROM_PARTIAL); |
|
object = t; |
|
} else { |
|
put_cpu_partial(s, page, 0); |
|
stat(s, CPU_PARTIAL_NODE); |
|
} |
|
if (!kmem_cache_has_cpu_partial(s) |
|
|| available > slub_cpu_partial(s) / 2) |
|
break; |
|
|
|
} |
|
spin_unlock(&n->list_lock); |
|
return object; |
|
} |
|
|
|
/* |
|
* Get a page from somewhere. Search in increasing NUMA distances. |
|
*/ |
|
static void *get_any_partial(struct kmem_cache *s, gfp_t flags, |
|
struct kmem_cache_cpu *c) |
|
{ |
|
#ifdef CONFIG_NUMA |
|
struct zonelist *zonelist; |
|
struct zoneref *z; |
|
struct zone *zone; |
|
enum zone_type highest_zoneidx = gfp_zone(flags); |
|
void *object; |
|
unsigned int cpuset_mems_cookie; |
|
|
|
/* |
|
* The defrag ratio allows a configuration of the tradeoffs between |
|
* inter node defragmentation and node local allocations. A lower |
|
* defrag_ratio increases the tendency to do local allocations |
|
* instead of attempting to obtain partial slabs from other nodes. |
|
* |
|
* If the defrag_ratio is set to 0 then kmalloc() always |
|
* returns node local objects. If the ratio is higher then kmalloc() |
|
* may return off node objects because partial slabs are obtained |
|
* from other nodes and filled up. |
|
* |
|
* If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100 |
|
* (which makes defrag_ratio = 1000) then every (well almost) |
|
* allocation will first attempt to defrag slab caches on other nodes. |
|
* This means scanning over all nodes to look for partial slabs which |
|
* may be expensive if we do it every time we are trying to find a slab |
|
* with available objects. |
|
*/ |
|
if (!s->remote_node_defrag_ratio || |
|
get_cycles() % 1024 > s->remote_node_defrag_ratio) |
|
return NULL; |
|
|
|
do { |
|
cpuset_mems_cookie = read_mems_allowed_begin(); |
|
zonelist = node_zonelist(mempolicy_slab_node(), flags); |
|
for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) { |
|
struct kmem_cache_node *n; |
|
|
|
n = get_node(s, zone_to_nid(zone)); |
|
|
|
if (n && cpuset_zone_allowed(zone, flags) && |
|
n->nr_partial > s->min_partial) { |
|
object = get_partial_node(s, n, c, flags); |
|
if (object) { |
|
/* |
|
* Don't check read_mems_allowed_retry() |
|
* here - if mems_allowed was updated in |
|
* parallel, that was a harmless race |
|
* between allocation and the cpuset |
|
* update |
|
*/ |
|
return object; |
|
} |
|
} |
|
} |
|
} while (read_mems_allowed_retry(cpuset_mems_cookie)); |
|
#endif /* CONFIG_NUMA */ |
|
return NULL; |
|
} |
|
|
|
/* |
|
* Get a partial page, lock it and return it. |
|
*/ |
|
static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, |
|
struct kmem_cache_cpu *c) |
|
{ |
|
void *object; |
|
int searchnode = node; |
|
|
|
if (node == NUMA_NO_NODE) |
|
searchnode = numa_mem_id(); |
|
|
|
object = get_partial_node(s, get_node(s, searchnode), c, flags); |
|
if (object || node != NUMA_NO_NODE) |
|
return object; |
|
|
|
return get_any_partial(s, flags, c); |
|
} |
|
|
|
#ifdef CONFIG_PREEMPTION |
|
/* |
|
* Calculate the next globally unique transaction for disambiguation |
|
* during cmpxchg. The transactions start with the cpu number and are then |
|
* incremented by CONFIG_NR_CPUS. |
|
*/ |
|
#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS) |
|
#else |
|
/* |
|
* No preemption supported therefore also no need to check for |
|
* different cpus. |
|
*/ |
|
#define TID_STEP 1 |
|
#endif |
|
|
|
static inline unsigned long next_tid(unsigned long tid) |
|
{ |
|
return tid + TID_STEP; |
|
} |
|
|
|
#ifdef SLUB_DEBUG_CMPXCHG |
|
static inline unsigned int tid_to_cpu(unsigned long tid) |
|
{ |
|
return tid % TID_STEP; |
|
} |
|
|
|
static inline unsigned long tid_to_event(unsigned long tid) |
|
{ |
|
return tid / TID_STEP; |
|
} |
|
#endif |
|
|
|
static inline unsigned int init_tid(int cpu) |
|
{ |
|
return cpu; |
|
} |
|
|
|
static inline void note_cmpxchg_failure(const char *n, |
|
const struct kmem_cache *s, unsigned long tid) |
|
{ |
|
#ifdef SLUB_DEBUG_CMPXCHG |
|
unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid); |
|
|
|
pr_info("%s %s: cmpxchg redo ", n, s->name); |
|
|
|
#ifdef CONFIG_PREEMPTION |
|
if (tid_to_cpu(tid) != tid_to_cpu(actual_tid)) |
|
pr_warn("due to cpu change %d -> %d\n", |
|
tid_to_cpu(tid), tid_to_cpu(actual_tid)); |
|
else |
|
#endif |
|
if (tid_to_event(tid) != tid_to_event(actual_tid)) |
|
pr_warn("due to cpu running other code. Event %ld->%ld\n", |
|
tid_to_event(tid), tid_to_event(actual_tid)); |
|
else |
|
pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n", |
|
actual_tid, tid, next_tid(tid)); |
|
#endif |
|
stat(s, CMPXCHG_DOUBLE_CPU_FAIL); |
|
} |
|
|
|
static void init_kmem_cache_cpus(struct kmem_cache *s) |
|
{ |
|
int cpu; |
|
|
|
for_each_possible_cpu(cpu) |
|
per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu); |
|
} |
|
|
|
/* |
|
* Remove the cpu slab |
|
*/ |
|
static void deactivate_slab(struct kmem_cache *s, struct page *page, |
|
void *freelist, struct kmem_cache_cpu *c) |
|
{ |
|
enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE }; |
|
struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
|
int lock = 0, free_delta = 0; |
|
enum slab_modes l = M_NONE, m = M_NONE; |
|
void *nextfree, *freelist_iter, *freelist_tail; |
|
int tail = DEACTIVATE_TO_HEAD; |
|
struct page new; |
|
struct page old; |
|
|
|
if (page->freelist) { |
|
stat(s, DEACTIVATE_REMOTE_FREES); |
|
tail = DEACTIVATE_TO_TAIL; |
|
} |
|
|
|
/* |
|
* Stage one: Count the objects on cpu's freelist as free_delta and |
|
* remember the last object in freelist_tail for later splicing. |
|
*/ |
|
freelist_tail = NULL; |
|
freelist_iter = freelist; |
|
while (freelist_iter) { |
|
nextfree = get_freepointer(s, freelist_iter); |
|
|
|
/* |
|
* If 'nextfree' is invalid, it is possible that the object at |
|
* 'freelist_iter' is already corrupted. So isolate all objects |
|
* starting at 'freelist_iter' by skipping them. |
|
*/ |
|
if (freelist_corrupted(s, page, &freelist_iter, nextfree)) |
|
break; |
|
|
|
freelist_tail = freelist_iter; |
|
free_delta++; |
|
|
|
freelist_iter = nextfree; |
|
} |
|
|
|
/* |
|
* Stage two: Unfreeze the page while splicing the per-cpu |
|
* freelist to the head of page's freelist. |
|
* |
|
* Ensure that the page is unfrozen while the list presence |
|
* reflects the actual number of objects during unfreeze. |
|
* |
|
* We setup the list membership and then perform a cmpxchg |
|
* with the count. If there is a mismatch then the page |
|
* is not unfrozen but the page is on the wrong list. |
|
* |
|
* Then we restart the process which may have to remove |
|
* the page from the list that we just put it on again |
|
* because the number of objects in the slab may have |
|
* changed. |
|
*/ |
|
redo: |
|
|
|
old.freelist = READ_ONCE(page->freelist); |
|
old.counters = READ_ONCE(page->counters); |
|
VM_BUG_ON(!old.frozen); |
|
|
|
/* Determine target state of the slab */ |
|
new.counters = old.counters; |
|
if (freelist_tail) { |
|
new.inuse -= free_delta; |
|
set_freepointer(s, freelist_tail, old.freelist); |
|
new.freelist = freelist; |
|
} else |
|
new.freelist = old.freelist; |
|
|
|
new.frozen = 0; |
|
|
|
if (!new.inuse && n->nr_partial >= s->min_partial) |
|
m = M_FREE; |
|
else if (new.freelist) { |
|
m = M_PARTIAL; |
|
if (!lock) { |
|
lock = 1; |
|
/* |
|
* Taking the spinlock removes the possibility |
|
* that acquire_slab() will see a slab page that |
|
* is frozen |
|
*/ |
|
spin_lock(&n->list_lock); |
|
} |
|
} else { |
|
m = M_FULL; |
|
if (kmem_cache_debug_flags(s, SLAB_STORE_USER) && !lock) { |
|
lock = 1; |
|
/* |
|
* This also ensures that the scanning of full |
|
* slabs from diagnostic functions will not see |
|
* any frozen slabs. |
|
*/ |
|
spin_lock(&n->list_lock); |
|
} |
|
} |
|
|
|
if (l != m) { |
|
if (l == M_PARTIAL) |
|
remove_partial(n, page); |
|
else if (l == M_FULL) |
|
remove_full(s, n, page); |
|
|
|
if (m == M_PARTIAL) |
|
add_partial(n, page, tail); |
|
else if (m == M_FULL) |
|
add_full(s, n, page); |
|
} |
|
|
|
l = m; |
|
if (!__cmpxchg_double_slab(s, page, |
|
old.freelist, old.counters, |
|
new.freelist, new.counters, |
|
"unfreezing slab")) |
|
goto redo; |
|
|
|
if (lock) |
|
spin_unlock(&n->list_lock); |
|
|
|
if (m == M_PARTIAL) |
|
stat(s, tail); |
|
else if (m == M_FULL) |
|
stat(s, DEACTIVATE_FULL); |
|
else if (m == M_FREE) { |
|
stat(s, DEACTIVATE_EMPTY); |
|
discard_slab(s, page); |
|
stat(s, FREE_SLAB); |
|
} |
|
|
|
c->page = NULL; |
|
c->freelist = NULL; |
|
} |
|
|
|
/* |
|
* Unfreeze all the cpu partial slabs. |
|
* |
|
* This function must be called with interrupts disabled |
|
* for the cpu using c (or some other guarantee must be there |
|
* to guarantee no concurrent accesses). |
|
*/ |
|
static void unfreeze_partials(struct kmem_cache *s, |
|
struct kmem_cache_cpu *c) |
|
{ |
|
#ifdef CONFIG_SLUB_CPU_PARTIAL |
|
struct kmem_cache_node *n = NULL, *n2 = NULL; |
|
struct page *page, *discard_page = NULL; |
|
|
|
while ((page = slub_percpu_partial(c))) { |
|
struct page new; |
|
struct page old; |
|
|
|
slub_set_percpu_partial(c, page); |
|
|
|
n2 = get_node(s, page_to_nid(page)); |
|
if (n != n2) { |
|
if (n) |
|
spin_unlock(&n->list_lock); |
|
|
|
n = n2; |
|
spin_lock(&n->list_lock); |
|
} |
|
|
|
do { |
|
|
|
old.freelist = page->freelist; |
|
old.counters = page->counters; |
|
VM_BUG_ON(!old.frozen); |
|
|
|
new.counters = old.counters; |
|
new.freelist = old.freelist; |
|
|
|
new.frozen = 0; |
|
|
|
} while (!__cmpxchg_double_slab(s, page, |
|
old.freelist, old.counters, |
|
new.freelist, new.counters, |
|
"unfreezing slab")); |
|
|
|
if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) { |
|
page->next = discard_page; |
|
discard_page = page; |
|
} else { |
|
add_partial(n, page, DEACTIVATE_TO_TAIL); |
|
stat(s, FREE_ADD_PARTIAL); |
|
} |
|
} |
|
|
|
if (n) |
|
spin_unlock(&n->list_lock); |
|
|
|
while (discard_page) { |
|
page = discard_page; |
|
discard_page = discard_page->next; |
|
|
|
stat(s, DEACTIVATE_EMPTY); |
|
discard_slab(s, page); |
|
stat(s, FREE_SLAB); |
|
} |
|
#endif /* CONFIG_SLUB_CPU_PARTIAL */ |
|
} |
|
|
|
/* |
|
* Put a page that was just frozen (in __slab_free|get_partial_node) into a |
|
* partial page slot if available. |
|
* |
|
* If we did not find a slot then simply move all the partials to the |
|
* per node partial list. |
|
*/ |
|
static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) |
|
{ |
|
#ifdef CONFIG_SLUB_CPU_PARTIAL |
|
struct page *oldpage; |
|
int pages; |
|
int pobjects; |
|
|
|
preempt_disable(); |
|
do { |
|
pages = 0; |
|
pobjects = 0; |
|
oldpage = this_cpu_read(s->cpu_slab->partial); |
|
|
|
if (oldpage) { |
|
pobjects = oldpage->pobjects; |
|
pages = oldpage->pages; |
|
if (drain && pobjects > slub_cpu_partial(s)) { |
|
unsigned long flags; |
|
/* |
|
* partial array is full. Move the existing |
|
* set to the per node partial list. |
|
*/ |
|
local_irq_save(flags); |
|
unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); |
|
local_irq_restore(flags); |
|
oldpage = NULL; |
|
pobjects = 0; |
|
pages = 0; |
|
stat(s, CPU_PARTIAL_DRAIN); |
|
} |
|
} |
|
|
|
pages++; |
|
pobjects += page->objects - page->inuse; |
|
|
|
page->pages = pages; |
|
page->pobjects = pobjects; |
|
page->next = oldpage; |
|
|
|
} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) |
|
!= oldpage); |
|
if (unlikely(!slub_cpu_partial(s))) { |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); |
|
local_irq_restore(flags); |
|
} |
|
preempt_enable(); |
|
#endif /* CONFIG_SLUB_CPU_PARTIAL */ |
|
} |
|
|
|
static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) |
|
{ |
|
stat(s, CPUSLAB_FLUSH); |
|
deactivate_slab(s, c->page, c->freelist, c); |
|
|
|
c->tid = next_tid(c->tid); |
|
} |
|
|
|
/* |
|
* Flush cpu slab. |
|
* |
|
* Called from IPI handler with interrupts disabled. |
|
*/ |
|
static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) |
|
{ |
|
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); |
|
|
|
if (c->page) |
|
flush_slab(s, c); |
|
|
|
unfreeze_partials(s, c); |
|
} |
|
|
|
static void flush_cpu_slab(void *d) |
|
{ |
|
struct kmem_cache *s = d; |
|
|
|
__flush_cpu_slab(s, smp_processor_id()); |
|
} |
|
|
|
static bool has_cpu_slab(int cpu, void *info) |
|
{ |
|
struct kmem_cache *s = info; |
|
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); |
|
|
|
return c->page || slub_percpu_partial(c); |
|
} |
|
|
|
static void flush_all(struct kmem_cache *s) |
|
{ |
|
on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1); |
|
} |
|
|
|
/* |
|
* Use the cpu notifier to insure that the cpu slabs are flushed when |
|
* necessary. |
|
*/ |
|
static int slub_cpu_dead(unsigned int cpu) |
|
{ |
|
struct kmem_cache *s; |
|
unsigned long flags; |
|
|
|
mutex_lock(&slab_mutex); |
|
list_for_each_entry(s, &slab_caches, list) { |
|
local_irq_save(flags); |
|
__flush_cpu_slab(s, cpu); |
|
local_irq_restore(flags); |
|
} |
|
mutex_unlock(&slab_mutex); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Check if the objects in a per cpu structure fit numa |
|
* locality expectations. |
|
*/ |
|
static inline int node_match(struct page *page, int node) |
|
{ |
|
#ifdef CONFIG_NUMA |
|
if (node != NUMA_NO_NODE && page_to_nid(page) != node) |
|
return 0; |
|
#endif |
|
return 1; |
|
} |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
static int count_free(struct page *page) |
|
{ |
|
return page->objects - page->inuse; |
|
} |
|
|
|
static inline unsigned long node_nr_objs(struct kmem_cache_node *n) |
|
{ |
|
return atomic_long_read(&n->total_objects); |
|
} |
|
#endif /* CONFIG_SLUB_DEBUG */ |
|
|
|
#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS) |
|
static unsigned long count_partial(struct kmem_cache_node *n, |
|
int (*get_count)(struct page *)) |
|
{ |
|
unsigned long flags; |
|
unsigned long x = 0; |
|
struct page *page; |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
list_for_each_entry(page, &n->partial, slab_list) |
|
x += get_count(page); |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
return x; |
|
} |
|
#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */ |
|
|
|
static noinline void |
|
slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) |
|
{ |
|
#ifdef CONFIG_SLUB_DEBUG |
|
static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL, |
|
DEFAULT_RATELIMIT_BURST); |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs)) |
|
return; |
|
|
|
pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", |
|
nid, gfpflags, &gfpflags); |
|
pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n", |
|
s->name, s->object_size, s->size, oo_order(s->oo), |
|
oo_order(s->min)); |
|
|
|
if (oo_order(s->min) > get_order(s->object_size)) |
|
pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n", |
|
s->name); |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
unsigned long nr_slabs; |
|
unsigned long nr_objs; |
|
unsigned long nr_free; |
|
|
|
nr_free = count_partial(n, count_free); |
|
nr_slabs = node_nr_slabs(n); |
|
nr_objs = node_nr_objs(n); |
|
|
|
pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n", |
|
node, nr_slabs, nr_objs, nr_free); |
|
} |
|
#endif |
|
} |
|
|
|
static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, |
|
int node, struct kmem_cache_cpu **pc) |
|
{ |
|
void *freelist; |
|
struct kmem_cache_cpu *c = *pc; |
|
struct page *page; |
|
|
|
WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); |
|
|
|
freelist = get_partial(s, flags, node, c); |
|
|
|
if (freelist) |
|
return freelist; |
|
|
|
page = new_slab(s, flags, node); |
|
if (page) { |
|
c = raw_cpu_ptr(s->cpu_slab); |
|
if (c->page) |
|
flush_slab(s, c); |
|
|
|
/* |
|
* No other reference to the page yet so we can |
|
* muck around with it freely without cmpxchg |
|
*/ |
|
freelist = page->freelist; |
|
page->freelist = NULL; |
|
|
|
stat(s, ALLOC_SLAB); |
|
c->page = page; |
|
*pc = c; |
|
} |
|
|
|
return freelist; |
|
} |
|
|
|
static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags) |
|
{ |
|
if (unlikely(PageSlabPfmemalloc(page))) |
|
return gfp_pfmemalloc_allowed(gfpflags); |
|
|
|
return true; |
|
} |
|
|
|
/* |
|
* Check the page->freelist of a page and either transfer the freelist to the |
|
* per cpu freelist or deactivate the page. |
|
* |
|
* The page is still frozen if the return value is not NULL. |
|
* |
|
* If this function returns NULL then the page has been unfrozen. |
|
* |
|
* This function must be called with interrupt disabled. |
|
*/ |
|
static inline void *get_freelist(struct kmem_cache *s, struct page *page) |
|
{ |
|
struct page new; |
|
unsigned long counters; |
|
void *freelist; |
|
|
|
do { |
|
freelist = page->freelist; |
|
counters = page->counters; |
|
|
|
new.counters = counters; |
|
VM_BUG_ON(!new.frozen); |
|
|
|
new.inuse = page->objects; |
|
new.frozen = freelist != NULL; |
|
|
|
} while (!__cmpxchg_double_slab(s, page, |
|
freelist, counters, |
|
NULL, new.counters, |
|
"get_freelist")); |
|
|
|
return freelist; |
|
} |
|
|
|
/* |
|
* Slow path. The lockless freelist is empty or we need to perform |
|
* debugging duties. |
|
* |
|
* Processing is still very fast if new objects have been freed to the |
|
* regular freelist. In that case we simply take over the regular freelist |
|
* as the lockless freelist and zap the regular freelist. |
|
* |
|
* If that is not working then we fall back to the partial lists. We take the |
|
* first element of the freelist as the object to allocate now and move the |
|
* rest of the freelist to the lockless freelist. |
|
* |
|
* And if we were unable to get a new slab from the partial slab lists then |
|
* we need to allocate a new slab. This is the slowest path since it involves |
|
* a call to the page allocator and the setup of a new slab. |
|
* |
|
* Version of __slab_alloc to use when we know that interrupts are |
|
* already disabled (which is the case for bulk allocation). |
|
*/ |
|
static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, |
|
unsigned long addr, struct kmem_cache_cpu *c) |
|
{ |
|
void *freelist; |
|
struct page *page; |
|
|
|
stat(s, ALLOC_SLOWPATH); |
|
|
|
page = c->page; |
|
if (!page) { |
|
/* |
|
* if the node is not online or has no normal memory, just |
|
* ignore the node constraint |
|
*/ |
|
if (unlikely(node != NUMA_NO_NODE && |
|
!node_isset(node, slab_nodes))) |
|
node = NUMA_NO_NODE; |
|
goto new_slab; |
|
} |
|
redo: |
|
|
|
if (unlikely(!node_match(page, node))) { |
|
/* |
|
* same as above but node_match() being false already |
|
* implies node != NUMA_NO_NODE |
|
*/ |
|
if (!node_isset(node, slab_nodes)) { |
|
node = NUMA_NO_NODE; |
|
goto redo; |
|
} else { |
|
stat(s, ALLOC_NODE_MISMATCH); |
|
deactivate_slab(s, page, c->freelist, c); |
|
goto new_slab; |
|
} |
|
} |
|
|
|
/* |
|
* By rights, we should be searching for a slab page that was |
|
* PFMEMALLOC but right now, we are losing the pfmemalloc |
|
* information when the page leaves the per-cpu allocator |
|
*/ |
|
if (unlikely(!pfmemalloc_match(page, gfpflags))) { |
|
deactivate_slab(s, page, c->freelist, c); |
|
goto new_slab; |
|
} |
|
|
|
/* must check again c->freelist in case of cpu migration or IRQ */ |
|
freelist = c->freelist; |
|
if (freelist) |
|
goto load_freelist; |
|
|
|
freelist = get_freelist(s, page); |
|
|
|
if (!freelist) { |
|
c->page = NULL; |
|
stat(s, DEACTIVATE_BYPASS); |
|
goto new_slab; |
|
} |
|
|
|
stat(s, ALLOC_REFILL); |
|
|
|
load_freelist: |
|
/* |
|
* freelist is pointing to the list of objects to be used. |
|
* page is pointing to the page from which the objects are obtained. |
|
* That page must be frozen for per cpu allocations to work. |
|
*/ |
|
VM_BUG_ON(!c->page->frozen); |
|
c->freelist = get_freepointer(s, freelist); |
|
c->tid = next_tid(c->tid); |
|
return freelist; |
|
|
|
new_slab: |
|
|
|
if (slub_percpu_partial(c)) { |
|
page = c->page = slub_percpu_partial(c); |
|
slub_set_percpu_partial(c, page); |
|
stat(s, CPU_PARTIAL_ALLOC); |
|
goto redo; |
|
} |
|
|
|
freelist = new_slab_objects(s, gfpflags, node, &c); |
|
|
|
if (unlikely(!freelist)) { |
|
slab_out_of_memory(s, gfpflags, node); |
|
return NULL; |
|
} |
|
|
|
page = c->page; |
|
if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags))) |
|
goto load_freelist; |
|
|
|
/* Only entered in the debug case */ |
|
if (kmem_cache_debug(s) && |
|
!alloc_debug_processing(s, page, freelist, addr)) |
|
goto new_slab; /* Slab failed checks. Next slab needed */ |
|
|
|
deactivate_slab(s, page, get_freepointer(s, freelist), c); |
|
return freelist; |
|
} |
|
|
|
/* |
|
* Another one that disabled interrupt and compensates for possible |
|
* cpu changes by refetching the per cpu area pointer. |
|
*/ |
|
static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, |
|
unsigned long addr, struct kmem_cache_cpu *c) |
|
{ |
|
void *p; |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
#ifdef CONFIG_PREEMPTION |
|
/* |
|
* We may have been preempted and rescheduled on a different |
|
* cpu before disabling interrupts. Need to reload cpu area |
|
* pointer. |
|
*/ |
|
c = this_cpu_ptr(s->cpu_slab); |
|
#endif |
|
|
|
p = ___slab_alloc(s, gfpflags, node, addr, c); |
|
local_irq_restore(flags); |
|
return p; |
|
} |
|
|
|
/* |
|
* If the object has been wiped upon free, make sure it's fully initialized by |
|
* zeroing out freelist pointer. |
|
*/ |
|
static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s, |
|
void *obj) |
|
{ |
|
if (unlikely(slab_want_init_on_free(s)) && obj) |
|
memset((void *)((char *)kasan_reset_tag(obj) + s->offset), |
|
0, sizeof(void *)); |
|
} |
|
|
|
/* |
|
* Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) |
|
* have the fastpath folded into their functions. So no function call |
|
* overhead for requests that can be satisfied on the fastpath. |
|
* |
|
* The fastpath works by first checking if the lockless freelist can be used. |
|
* If not then __slab_alloc is called for slow processing. |
|
* |
|
* Otherwise we can simply pick the next object from the lockless free list. |
|
*/ |
|
static __always_inline void *slab_alloc_node(struct kmem_cache *s, |
|
gfp_t gfpflags, int node, unsigned long addr, size_t orig_size) |
|
{ |
|
void *object; |
|
struct kmem_cache_cpu *c; |
|
struct page *page; |
|
unsigned long tid; |
|
struct obj_cgroup *objcg = NULL; |
|
bool init = false; |
|
|
|
s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags); |
|
if (!s) |
|
return NULL; |
|
|
|
object = kfence_alloc(s, orig_size, gfpflags); |
|
if (unlikely(object)) |
|
goto out; |
|
|
|
redo: |
|
/* |
|
* Must read kmem_cache cpu data via this cpu ptr. Preemption is |
|
* enabled. We may switch back and forth between cpus while |
|
* reading from one cpu area. That does not matter as long |
|
* as we end up on the original cpu again when doing the cmpxchg. |
|
* |
|
* We should guarantee that tid and kmem_cache are retrieved on |
|
* the same cpu. It could be different if CONFIG_PREEMPTION so we need |
|
* to check if it is matched or not. |
|
*/ |
|
do { |
|
tid = this_cpu_read(s->cpu_slab->tid); |
|
c = raw_cpu_ptr(s->cpu_slab); |
|
} while (IS_ENABLED(CONFIG_PREEMPTION) && |
|
unlikely(tid != READ_ONCE(c->tid))); |
|
|
|
/* |
|
* Irqless object alloc/free algorithm used here depends on sequence |
|
* of fetching cpu_slab's data. tid should be fetched before anything |
|
* on c to guarantee that object and page associated with previous tid |
|
* won't be used with current tid. If we fetch tid first, object and |
|
* page could be one associated with next tid and our alloc/free |
|
* request will be failed. In this case, we will retry. So, no problem. |
|
*/ |
|
barrier(); |
|
|
|
/* |
|
* The transaction ids are globally unique per cpu and per operation on |
|
* a per cpu queue. Thus they can be guarantee that the cmpxchg_double |
|
* occurs on the right processor and that there was no operation on the |
|
* linked list in between. |
|
*/ |
|
|
|
object = c->freelist; |
|
page = c->page; |
|
if (unlikely(!object || !page || !node_match(page, node))) { |
|
object = __slab_alloc(s, gfpflags, node, addr, c); |
|
} else { |
|
void *next_object = get_freepointer_safe(s, object); |
|
|
|
/* |
|
* The cmpxchg will only match if there was no additional |
|
* operation and if we are on the right processor. |
|
* |
|
* The cmpxchg does the following atomically (without lock |
|
* semantics!) |
|
* 1. Relocate first pointer to the current per cpu area. |
|
* 2. Verify that tid and freelist have not been changed |
|
* 3. If they were not changed replace tid and freelist |
|
* |
|
* Since this is without lock semantics the protection is only |
|
* against code executing on this cpu *not* from access by |
|
* other cpus. |
|
*/ |
|
if (unlikely(!this_cpu_cmpxchg_double( |
|
s->cpu_slab->freelist, s->cpu_slab->tid, |
|
object, tid, |
|
next_object, next_tid(tid)))) { |
|
|
|
note_cmpxchg_failure("slab_alloc", s, tid); |
|
goto redo; |
|
} |
|
prefetch_freepointer(s, next_object); |
|
stat(s, ALLOC_FASTPATH); |
|
} |
|
|
|
maybe_wipe_obj_freeptr(s, object); |
|
init = slab_want_init_on_alloc(gfpflags, s); |
|
|
|
out: |
|
slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init); |
|
|
|
return object; |
|
} |
|
|
|
static __always_inline void *slab_alloc(struct kmem_cache *s, |
|
gfp_t gfpflags, unsigned long addr, size_t orig_size) |
|
{ |
|
return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr, orig_size); |
|
} |
|
|
|
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) |
|
{ |
|
void *ret = slab_alloc(s, gfpflags, _RET_IP_, s->object_size); |
|
|
|
trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, |
|
s->size, gfpflags); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc); |
|
|
|
#ifdef CONFIG_TRACING |
|
void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) |
|
{ |
|
void *ret = slab_alloc(s, gfpflags, _RET_IP_, size); |
|
trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); |
|
ret = kasan_kmalloc(s, ret, size, gfpflags); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_trace); |
|
#endif |
|
|
|
#ifdef CONFIG_NUMA |
|
void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) |
|
{ |
|
void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, s->object_size); |
|
|
|
trace_kmem_cache_alloc_node(_RET_IP_, ret, |
|
s->object_size, s->size, gfpflags, node); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_node); |
|
|
|
#ifdef CONFIG_TRACING |
|
void *kmem_cache_alloc_node_trace(struct kmem_cache *s, |
|
gfp_t gfpflags, |
|
int node, size_t size) |
|
{ |
|
void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, size); |
|
|
|
trace_kmalloc_node(_RET_IP_, ret, |
|
size, s->size, gfpflags, node); |
|
|
|
ret = kasan_kmalloc(s, ret, size, gfpflags); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_node_trace); |
|
#endif |
|
#endif /* CONFIG_NUMA */ |
|
|
|
/* |
|
* Slow path handling. This may still be called frequently since objects |
|
* have a longer lifetime than the cpu slabs in most processing loads. |
|
* |
|
* So we still attempt to reduce cache line usage. Just take the slab |
|
* lock and free the item. If there is no additional partial page |
|
* handling required then we can return immediately. |
|
*/ |
|
static void __slab_free(struct kmem_cache *s, struct page *page, |
|
void *head, void *tail, int cnt, |
|
unsigned long addr) |
|
|
|
{ |
|
void *prior; |
|
int was_frozen; |
|
struct page new; |
|
unsigned long counters; |
|
struct kmem_cache_node *n = NULL; |
|
unsigned long flags; |
|
|
|
stat(s, FREE_SLOWPATH); |
|
|
|
if (kfence_free(head)) |
|
return; |
|
|
|
if (kmem_cache_debug(s) && |
|
!free_debug_processing(s, page, head, tail, cnt, addr)) |
|
return; |
|
|
|
do { |
|
if (unlikely(n)) { |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
n = NULL; |
|
} |
|
prior = page->freelist; |
|
counters = page->counters; |
|
set_freepointer(s, tail, prior); |
|
new.counters = counters; |
|
was_frozen = new.frozen; |
|
new.inuse -= cnt; |
|
if ((!new.inuse || !prior) && !was_frozen) { |
|
|
|
if (kmem_cache_has_cpu_partial(s) && !prior) { |
|
|
|
/* |
|
* Slab was on no list before and will be |
|
* partially empty |
|
* We can defer the list move and instead |
|
* freeze it. |
|
*/ |
|
new.frozen = 1; |
|
|
|
} else { /* Needs to be taken off a list */ |
|
|
|
n = get_node(s, page_to_nid(page)); |
|
/* |
|
* Speculatively acquire the list_lock. |
|
* If the cmpxchg does not succeed then we may |
|
* drop the list_lock without any processing. |
|
* |
|
* Otherwise the list_lock will synchronize with |
|
* other processors updating the list of slabs. |
|
*/ |
|
spin_lock_irqsave(&n->list_lock, flags); |
|
|
|
} |
|
} |
|
|
|
} while (!cmpxchg_double_slab(s, page, |
|
prior, counters, |
|
head, new.counters, |
|
"__slab_free")); |
|
|
|
if (likely(!n)) { |
|
|
|
if (likely(was_frozen)) { |
|
/* |
|
* The list lock was not taken therefore no list |
|
* activity can be necessary. |
|
*/ |
|
stat(s, FREE_FROZEN); |
|
} else if (new.frozen) { |
|
/* |
|
* If we just froze the page then put it onto the |
|
* per cpu partial list. |
|
*/ |
|
put_cpu_partial(s, page, 1); |
|
stat(s, CPU_PARTIAL_FREE); |
|
} |
|
|
|
return; |
|
} |
|
|
|
if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) |
|
goto slab_empty; |
|
|
|
/* |
|
* Objects left in the slab. If it was not on the partial list before |
|
* then add it. |
|
*/ |
|
if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) { |
|
remove_full(s, n, page); |
|
add_partial(n, page, DEACTIVATE_TO_TAIL); |
|
stat(s, FREE_ADD_PARTIAL); |
|
} |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
return; |
|
|
|
slab_empty: |
|
if (prior) { |
|
/* |
|
* Slab on the partial list. |
|
*/ |
|
remove_partial(n, page); |
|
stat(s, FREE_REMOVE_PARTIAL); |
|
} else { |
|
/* Slab must be on the full list */ |
|
remove_full(s, n, page); |
|
} |
|
|
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
stat(s, FREE_SLAB); |
|
discard_slab(s, page); |
|
} |
|
|
|
/* |
|
* Fastpath with forced inlining to produce a kfree and kmem_cache_free that |
|
* can perform fastpath freeing without additional function calls. |
|
* |
|
* The fastpath is only possible if we are freeing to the current cpu slab |
|
* of this processor. This typically the case if we have just allocated |
|
* the item before. |
|
* |
|
* If fastpath is not possible then fall back to __slab_free where we deal |
|
* with all sorts of special processing. |
|
* |
|
* Bulk free of a freelist with several objects (all pointing to the |
|
* same page) possible by specifying head and tail ptr, plus objects |
|
* count (cnt). Bulk free indicated by tail pointer being set. |
|
*/ |
|
static __always_inline void do_slab_free(struct kmem_cache *s, |
|
struct page *page, void *head, void *tail, |
|
int cnt, unsigned long addr) |
|
{ |
|
void *tail_obj = tail ? : head; |
|
struct kmem_cache_cpu *c; |
|
unsigned long tid; |
|
|
|
memcg_slab_free_hook(s, &head, 1); |
|
redo: |
|
/* |
|
* Determine the currently cpus per cpu slab. |
|
* The cpu may change afterward. However that does not matter since |
|
* data is retrieved via this pointer. If we are on the same cpu |
|
* during the cmpxchg then the free will succeed. |
|
*/ |
|
do { |
|
tid = this_cpu_read(s->cpu_slab->tid); |
|
c = raw_cpu_ptr(s->cpu_slab); |
|
} while (IS_ENABLED(CONFIG_PREEMPTION) && |
|
unlikely(tid != READ_ONCE(c->tid))); |
|
|
|
/* Same with comment on barrier() in slab_alloc_node() */ |
|
barrier(); |
|
|
|
if (likely(page == c->page)) { |
|
void **freelist = READ_ONCE(c->freelist); |
|
|
|
set_freepointer(s, tail_obj, freelist); |
|
|
|
if (unlikely(!this_cpu_cmpxchg_double( |
|
s->cpu_slab->freelist, s->cpu_slab->tid, |
|
freelist, tid, |
|
head, next_tid(tid)))) { |
|
|
|
note_cmpxchg_failure("slab_free", s, tid); |
|
goto redo; |
|
} |
|
stat(s, FREE_FASTPATH); |
|
} else |
|
__slab_free(s, page, head, tail_obj, cnt, addr); |
|
|
|
} |
|
|
|
static __always_inline void slab_free(struct kmem_cache *s, struct page *page, |
|
void *head, void *tail, int cnt, |
|
unsigned long addr) |
|
{ |
|
/* |
|
* With KASAN enabled slab_free_freelist_hook modifies the freelist |
|
* to remove objects, whose reuse must be delayed. |
|
*/ |
|
if (slab_free_freelist_hook(s, &head, &tail)) |
|
do_slab_free(s, page, head, tail, cnt, addr); |
|
} |
|
|
|
#ifdef CONFIG_KASAN_GENERIC |
|
void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr) |
|
{ |
|
do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr); |
|
} |
|
#endif |
|
|
|
void kmem_cache_free(struct kmem_cache *s, void *x) |
|
{ |
|
s = cache_from_obj(s, x); |
|
if (!s) |
|
return; |
|
slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_); |
|
trace_kmem_cache_free(_RET_IP_, x, s->name); |
|
} |
|
EXPORT_SYMBOL(kmem_cache_free); |
|
|
|
struct detached_freelist { |
|
struct page *page; |
|
void *tail; |
|
void *freelist; |
|
int cnt; |
|
struct kmem_cache *s; |
|
}; |
|
|
|
/* |
|
* This function progressively scans the array with free objects (with |
|
* a limited look ahead) and extract objects belonging to the same |
|
* page. It builds a detached freelist directly within the given |
|
* page/objects. This can happen without any need for |
|
* synchronization, because the objects are owned by running process. |
|
* The freelist is build up as a single linked list in the objects. |
|
* The idea is, that this detached freelist can then be bulk |
|
* transferred to the real freelist(s), but only requiring a single |
|
* synchronization primitive. Look ahead in the array is limited due |
|
* to performance reasons. |
|
*/ |
|
static inline |
|
int build_detached_freelist(struct kmem_cache *s, size_t size, |
|
void **p, struct detached_freelist *df) |
|
{ |
|
size_t first_skipped_index = 0; |
|
int lookahead = 3; |
|
void *object; |
|
struct page *page; |
|
|
|
/* Always re-init detached_freelist */ |
|
df->page = NULL; |
|
|
|
do { |
|
object = p[--size]; |
|
/* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */ |
|
} while (!object && size); |
|
|
|
if (!object) |
|
return 0; |
|
|
|
page = virt_to_head_page(object); |
|
if (!s) { |
|
/* Handle kalloc'ed objects */ |
|
if (unlikely(!PageSlab(page))) { |
|
BUG_ON(!PageCompound(page)); |
|
kfree_hook(object); |
|
__free_pages(page, compound_order(page)); |
|
p[size] = NULL; /* mark object processed */ |
|
return size; |
|
} |
|
/* Derive kmem_cache from object */ |
|
df->s = page->slab_cache; |
|
} else { |
|
df->s = cache_from_obj(s, object); /* Support for memcg */ |
|
} |
|
|
|
if (is_kfence_address(object)) { |
|
slab_free_hook(df->s, object, false); |
|
__kfence_free(object); |
|
p[size] = NULL; /* mark object processed */ |
|
return size; |
|
} |
|
|
|
/* Start new detached freelist */ |
|
df->page = page; |
|
set_freepointer(df->s, object, NULL); |
|
df->tail = object; |
|
df->freelist = object; |
|
p[size] = NULL; /* mark object processed */ |
|
df->cnt = 1; |
|
|
|
while (size) { |
|
object = p[--size]; |
|
if (!object) |
|
continue; /* Skip processed objects */ |
|
|
|
/* df->page is always set at this point */ |
|
if (df->page == virt_to_head_page(object)) { |
|
/* Opportunity build freelist */ |
|
set_freepointer(df->s, object, df->freelist); |
|
df->freelist = object; |
|
df->cnt++; |
|
p[size] = NULL; /* mark object processed */ |
|
|
|
continue; |
|
} |
|
|
|
/* Limit look ahead search */ |
|
if (!--lookahead) |
|
break; |
|
|
|
if (!first_skipped_index) |
|
first_skipped_index = size + 1; |
|
} |
|
|
|
return first_skipped_index; |
|
} |
|
|
|
/* Note that interrupts must be enabled when calling this function. */ |
|
void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p) |
|
{ |
|
if (WARN_ON(!size)) |
|
return; |
|
|
|
memcg_slab_free_hook(s, p, size); |
|
do { |
|
struct detached_freelist df; |
|
|
|
size = build_detached_freelist(s, size, p, &df); |
|
if (!df.page) |
|
continue; |
|
|
|
slab_free(df.s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_); |
|
} while (likely(size)); |
|
} |
|
EXPORT_SYMBOL(kmem_cache_free_bulk); |
|
|
|
/* Note that interrupts must be enabled when calling this function. */ |
|
int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, |
|
void **p) |
|
{ |
|
struct kmem_cache_cpu *c; |
|
int i; |
|
struct obj_cgroup *objcg = NULL; |
|
|
|
/* memcg and kmem_cache debug support */ |
|
s = slab_pre_alloc_hook(s, &objcg, size, flags); |
|
if (unlikely(!s)) |
|
return false; |
|
/* |
|
* Drain objects in the per cpu slab, while disabling local |
|
* IRQs, which protects against PREEMPT and interrupts |
|
* handlers invoking normal fastpath. |
|
*/ |
|
local_irq_disable(); |
|
c = this_cpu_ptr(s->cpu_slab); |
|
|
|
for (i = 0; i < size; i++) { |
|
void *object = kfence_alloc(s, s->object_size, flags); |
|
|
|
if (unlikely(object)) { |
|
p[i] = object; |
|
continue; |
|
} |
|
|
|
object = c->freelist; |
|
if (unlikely(!object)) { |
|
/* |
|
* We may have removed an object from c->freelist using |
|
* the fastpath in the previous iteration; in that case, |
|
* c->tid has not been bumped yet. |
|
* Since ___slab_alloc() may reenable interrupts while |
|
* allocating memory, we should bump c->tid now. |
|
*/ |
|
c->tid = next_tid(c->tid); |
|
|
|
/* |
|
* Invoking slow path likely have side-effect |
|
* of re-populating per CPU c->freelist |
|
*/ |
|
p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE, |
|
_RET_IP_, c); |
|
if (unlikely(!p[i])) |
|
goto error; |
|
|
|
c = this_cpu_ptr(s->cpu_slab); |
|
maybe_wipe_obj_freeptr(s, p[i]); |
|
|
|
continue; /* goto for-loop */ |
|
} |
|
c->freelist = get_freepointer(s, object); |
|
p[i] = object; |
|
maybe_wipe_obj_freeptr(s, p[i]); |
|
} |
|
c->tid = next_tid(c->tid); |
|
local_irq_enable(); |
|
|
|
/* |
|
* memcg and kmem_cache debug support and memory initialization. |
|
* Done outside of the IRQ disabled fastpath loop. |
|
*/ |
|
slab_post_alloc_hook(s, objcg, flags, size, p, |
|
slab_want_init_on_alloc(flags, s)); |
|
return i; |
|
error: |
|
local_irq_enable(); |
|
slab_post_alloc_hook(s, objcg, flags, i, p, false); |
|
__kmem_cache_free_bulk(s, i, p); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_bulk); |
|
|
|
|
|
/* |
|
* Object placement in a slab is made very easy because we always start at |
|
* offset 0. If we tune the size of the object to the alignment then we can |
|
* get the required alignment by putting one properly sized object after |
|
* another. |
|
* |
|
* Notice that the allocation order determines the sizes of the per cpu |
|
* caches. Each processor has always one slab available for allocations. |
|
* Increasing the allocation order reduces the number of times that slabs |
|
* must be moved on and off the partial lists and is therefore a factor in |
|
* locking overhead. |
|
*/ |
|
|
|
/* |
|
* Minimum / Maximum order of slab pages. This influences locking overhead |
|
* and slab fragmentation. A higher order reduces the number of partial slabs |
|
* and increases the number of allocations possible without having to |
|
* take the list_lock. |
|
*/ |
|
static unsigned int slub_min_order; |
|
static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER; |
|
static unsigned int slub_min_objects; |
|
|
|
/* |
|
* Calculate the order of allocation given an slab object size. |
|
* |
|
* The order of allocation has significant impact on performance and other |
|
* system components. Generally order 0 allocations should be preferred since |
|
* order 0 does not cause fragmentation in the page allocator. Larger objects |
|
* be problematic to put into order 0 slabs because there may be too much |
|
* unused space left. We go to a higher order if more than 1/16th of the slab |
|
* would be wasted. |
|
* |
|
* In order to reach satisfactory performance we must ensure that a minimum |
|
* number of objects is in one slab. Otherwise we may generate too much |
|
* activity on the partial lists which requires taking the list_lock. This is |
|
* less a concern for large slabs though which are rarely used. |
|
* |
|
* slub_max_order specifies the order where we begin to stop considering the |
|
* number of objects in a slab as critical. If we reach slub_max_order then |
|
* we try to keep the page order as low as possible. So we accept more waste |
|
* of space in favor of a small page order. |
|
* |
|
* Higher order allocations also allow the placement of more objects in a |
|
* slab and thereby reduce object handling overhead. If the user has |
|
* requested a higher minimum order then we start with that one instead of |
|
* the smallest order which will fit the object. |
|
*/ |
|
static inline unsigned int slab_order(unsigned int size, |
|
unsigned int min_objects, unsigned int max_order, |
|
unsigned int fract_leftover) |
|
{ |
|
unsigned int min_order = slub_min_order; |
|
unsigned int order; |
|
|
|
if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE) |
|
return get_order(size * MAX_OBJS_PER_PAGE) - 1; |
|
|
|
for (order = max(min_order, (unsigned int)get_order(min_objects * size)); |
|
order <= max_order; order++) { |
|
|
|
unsigned int slab_size = (unsigned int)PAGE_SIZE << order; |
|
unsigned int rem; |
|
|
|
rem = slab_size % size; |
|
|
|
if (rem <= slab_size / fract_leftover) |
|
break; |
|
} |
|
|
|
return order; |
|
} |
|
|
|
static inline int calculate_order(unsigned int size) |
|
{ |
|
unsigned int order; |
|
unsigned int min_objects; |
|
unsigned int max_objects; |
|
unsigned int nr_cpus; |
|
|
|
/* |
|
* Attempt to find best configuration for a slab. This |
|
* works by first attempting to generate a layout with |
|
* the best configuration and backing off gradually. |
|
* |
|
* First we increase the acceptable waste in a slab. Then |
|
* we reduce the minimum objects required in a slab. |
|
*/ |
|
min_objects = slub_min_objects; |
|
if (!min_objects) { |
|
/* |
|
* Some architectures will only update present cpus when |
|
* onlining them, so don't trust the number if it's just 1. But |
|
* we also don't want to use nr_cpu_ids always, as on some other |
|
* architectures, there can be many possible cpus, but never |
|
* onlined. Here we compromise between trying to avoid too high |
|
* order on systems that appear larger than they are, and too |
|
* low order on systems that appear smaller than they are. |
|
*/ |
|
nr_cpus = num_present_cpus(); |
|
if (nr_cpus <= 1) |
|
nr_cpus = nr_cpu_ids; |
|
min_objects = 4 * (fls(nr_cpus) + 1); |
|
} |
|
max_objects = order_objects(slub_max_order, size); |
|
min_objects = min(min_objects, max_objects); |
|
|
|
while (min_objects > 1) { |
|
unsigned int fraction; |
|
|
|
fraction = 16; |
|
while (fraction >= 4) { |
|
order = slab_order(size, min_objects, |
|
slub_max_order, fraction); |
|
if (order <= slub_max_order) |
|
return order; |
|
fraction /= 2; |
|
} |
|
min_objects--; |
|
} |
|
|
|
/* |
|
* We were unable to place multiple objects in a slab. Now |
|
* lets see if we can place a single object there. |
|
*/ |
|
order = slab_order(size, 1, slub_max_order, 1); |
|
if (order <= slub_max_order) |
|
return order; |
|
|
|
/* |
|
* Doh this slab cannot be placed using slub_max_order. |
|
*/ |
|
order = slab_order(size, 1, MAX_ORDER, 1); |
|
if (order < MAX_ORDER) |
|
return order; |
|
return -ENOSYS; |
|
} |
|
|
|
static void |
|
init_kmem_cache_node(struct kmem_cache_node *n) |
|
{ |
|
n->nr_partial = 0; |
|
spin_lock_init(&n->list_lock); |
|
INIT_LIST_HEAD(&n->partial); |
|
#ifdef CONFIG_SLUB_DEBUG |
|
atomic_long_set(&n->nr_slabs, 0); |
|
atomic_long_set(&n->total_objects, 0); |
|
INIT_LIST_HEAD(&n->full); |
|
#endif |
|
} |
|
|
|
static inline int alloc_kmem_cache_cpus(struct kmem_cache *s) |
|
{ |
|
BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE < |
|
KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu)); |
|
|
|
/* |
|
* Must align to double word boundary for the double cmpxchg |
|
* instructions to work; see __pcpu_double_call_return_bool(). |
|
*/ |
|
s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu), |
|
2 * sizeof(void *)); |
|
|
|
if (!s->cpu_slab) |
|
return 0; |
|
|
|
init_kmem_cache_cpus(s); |
|
|
|
return 1; |
|
} |
|
|
|
static struct kmem_cache *kmem_cache_node; |
|
|
|
/* |
|
* No kmalloc_node yet so do it by hand. We know that this is the first |
|
* slab on the node for this slabcache. There are no concurrent accesses |
|
* possible. |
|
* |
|
* Note that this function only works on the kmem_cache_node |
|
* when allocating for the kmem_cache_node. This is used for bootstrapping |
|
* memory on a fresh node that has no slab structures yet. |
|
*/ |
|
static void early_kmem_cache_node_alloc(int node) |
|
{ |
|
struct page *page; |
|
struct kmem_cache_node *n; |
|
|
|
BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node)); |
|
|
|
page = new_slab(kmem_cache_node, GFP_NOWAIT, node); |
|
|
|
BUG_ON(!page); |
|
if (page_to_nid(page) != node) { |
|
pr_err("SLUB: Unable to allocate memory from node %d\n", node); |
|
pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n"); |
|
} |
|
|
|
n = page->freelist; |
|
BUG_ON(!n); |
|
#ifdef CONFIG_SLUB_DEBUG |
|
init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); |
|
init_tracking(kmem_cache_node, n); |
|
#endif |
|
n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false); |
|
page->freelist = get_freepointer(kmem_cache_node, n); |
|
page->inuse = 1; |
|
page->frozen = 0; |
|
kmem_cache_node->node[node] = n; |
|
init_kmem_cache_node(n); |
|
inc_slabs_node(kmem_cache_node, node, page->objects); |
|
|
|
/* |
|
* No locks need to be taken here as it has just been |
|
* initialized and there is no concurrent access. |
|
*/ |
|
__add_partial(n, page, DEACTIVATE_TO_HEAD); |
|
} |
|
|
|
static void free_kmem_cache_nodes(struct kmem_cache *s) |
|
{ |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
s->node[node] = NULL; |
|
kmem_cache_free(kmem_cache_node, n); |
|
} |
|
} |
|
|
|
void __kmem_cache_release(struct kmem_cache *s) |
|
{ |
|
cache_random_seq_destroy(s); |
|
free_percpu(s->cpu_slab); |
|
free_kmem_cache_nodes(s); |
|
} |
|
|
|
static int init_kmem_cache_nodes(struct kmem_cache *s) |
|
{ |
|
int node; |
|
|
|
for_each_node_mask(node, slab_nodes) { |
|
struct kmem_cache_node *n; |
|
|
|
if (slab_state == DOWN) { |
|
early_kmem_cache_node_alloc(node); |
|
continue; |
|
} |
|
n = kmem_cache_alloc_node(kmem_cache_node, |
|
GFP_KERNEL, node); |
|
|
|
if (!n) { |
|
free_kmem_cache_nodes(s); |
|
return 0; |
|
} |
|
|
|
init_kmem_cache_node(n); |
|
s->node[node] = n; |
|
} |
|
return 1; |
|
} |
|
|
|
static void set_min_partial(struct kmem_cache *s, unsigned long min) |
|
{ |
|
if (min < MIN_PARTIAL) |
|
min = MIN_PARTIAL; |
|
else if (min > MAX_PARTIAL) |
|
min = MAX_PARTIAL; |
|
s->min_partial = min; |
|
} |
|
|
|
static void set_cpu_partial(struct kmem_cache *s) |
|
{ |
|
#ifdef CONFIG_SLUB_CPU_PARTIAL |
|
/* |
|
* cpu_partial determined the maximum number of objects kept in the |
|
* per cpu partial lists of a processor. |
|
* |
|
* Per cpu partial lists mainly contain slabs that just have one |
|
* object freed. If they are used for allocation then they can be |
|
* filled up again with minimal effort. The slab will never hit the |
|
* per node partial lists and therefore no locking will be required. |
|
* |
|
* This setting also determines |
|
* |
|
* A) The number of objects from per cpu partial slabs dumped to the |
|
* per node list when we reach the limit. |
|
* B) The number of objects in cpu partial slabs to extract from the |
|
* per node list when we run out of per cpu objects. We only fetch |
|
* 50% to keep some capacity around for frees. |
|
*/ |
|
if (!kmem_cache_has_cpu_partial(s)) |
|
slub_set_cpu_partial(s, 0); |
|
else if (s->size >= PAGE_SIZE) |
|
slub_set_cpu_partial(s, 2); |
|
else if (s->size >= 1024) |
|
slub_set_cpu_partial(s, 6); |
|
else if (s->size >= 256) |
|
slub_set_cpu_partial(s, 13); |
|
else |
|
slub_set_cpu_partial(s, 30); |
|
#endif |
|
} |
|
|
|
/* |
|
* calculate_sizes() determines the order and the distribution of data within |
|
* a slab object. |
|
*/ |
|
static int calculate_sizes(struct kmem_cache *s, int forced_order) |
|
{ |
|
slab_flags_t flags = s->flags; |
|
unsigned int size = s->object_size; |
|
unsigned int order; |
|
|
|
/* |
|
* Round up object size to the next word boundary. We can only |
|
* place the free pointer at word boundaries and this determines |
|
* the possible location of the free pointer. |
|
*/ |
|
size = ALIGN(size, sizeof(void *)); |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
/* |
|
* Determine if we can poison the object itself. If the user of |
|
* the slab may touch the object after free or before allocation |
|
* then we should never poison the object itself. |
|
*/ |
|
if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) && |
|
!s->ctor) |
|
s->flags |= __OBJECT_POISON; |
|
else |
|
s->flags &= ~__OBJECT_POISON; |
|
|
|
|
|
/* |
|
* If we are Redzoning then check if there is some space between the |
|
* end of the object and the free pointer. If not then add an |
|
* additional word to have some bytes to store Redzone information. |
|
*/ |
|
if ((flags & SLAB_RED_ZONE) && size == s->object_size) |
|
size += sizeof(void *); |
|
#endif |
|
|
|
/* |
|
* With that we have determined the number of bytes in actual use |
|
* by the object and redzoning. |
|
*/ |
|
s->inuse = size; |
|
|
|
if ((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) || |
|
((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) || |
|
s->ctor) { |
|
/* |
|
* Relocate free pointer after the object if it is not |
|
* permitted to overwrite the first word of the object on |
|
* kmem_cache_free. |
|
* |
|
* This is the case if we do RCU, have a constructor or |
|
* destructor, are poisoning the objects, or are |
|
* redzoning an object smaller than sizeof(void *). |
|
* |
|
* The assumption that s->offset >= s->inuse means free |
|
* pointer is outside of the object is used in the |
|
* freeptr_outside_object() function. If that is no |
|
* longer true, the function needs to be modified. |
|
*/ |
|
s->offset = size; |
|
size += sizeof(void *); |
|
} else { |
|
/* |
|
* Store freelist pointer near middle of object to keep |
|
* it away from the edges of the object to avoid small |
|
* sized over/underflows from neighboring allocations. |
|
*/ |
|
s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *)); |
|
} |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
if (flags & SLAB_STORE_USER) |
|
/* |
|
* Need to store information about allocs and frees after |
|
* the object. |
|
*/ |
|
size += 2 * sizeof(struct track); |
|
#endif |
|
|
|
kasan_cache_create(s, &size, &s->flags); |
|
#ifdef CONFIG_SLUB_DEBUG |
|
if (flags & SLAB_RED_ZONE) { |
|
/* |
|
* Add some empty padding so that we can catch |
|
* overwrites from earlier objects rather than let |
|
* tracking information or the free pointer be |
|
* corrupted if a user writes before the start |
|
* of the object. |
|
*/ |
|
size += sizeof(void *); |
|
|
|
s->red_left_pad = sizeof(void *); |
|
s->red_left_pad = ALIGN(s->red_left_pad, s->align); |
|
size += s->red_left_pad; |
|
} |
|
#endif |
|
|
|
/* |
|
* SLUB stores one object immediately after another beginning from |
|
* offset 0. In order to align the objects we have to simply size |
|
* each object to conform to the alignment. |
|
*/ |
|
size = ALIGN(size, s->align); |
|
s->size = size; |
|
s->reciprocal_size = reciprocal_value(size); |
|
if (forced_order >= 0) |
|
order = forced_order; |
|
else |
|
order = calculate_order(size); |
|
|
|
if ((int)order < 0) |
|
return 0; |
|
|
|
s->allocflags = 0; |
|
if (order) |
|
s->allocflags |= __GFP_COMP; |
|
|
|
if (s->flags & SLAB_CACHE_DMA) |
|
s->allocflags |= GFP_DMA; |
|
|
|
if (s->flags & SLAB_CACHE_DMA32) |
|
s->allocflags |= GFP_DMA32; |
|
|
|
if (s->flags & SLAB_RECLAIM_ACCOUNT) |
|
s->allocflags |= __GFP_RECLAIMABLE; |
|
|
|
/* |
|
* Determine the number of objects per slab |
|
*/ |
|
s->oo = oo_make(order, size); |
|
s->min = oo_make(get_order(size), size); |
|
if (oo_objects(s->oo) > oo_objects(s->max)) |
|
s->max = s->oo; |
|
|
|
return !!oo_objects(s->oo); |
|
} |
|
|
|
static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags) |
|
{ |
|
s->flags = kmem_cache_flags(s->size, flags, s->name); |
|
#ifdef CONFIG_SLAB_FREELIST_HARDENED |
|
s->random = get_random_long(); |
|
#endif |
|
|
|
if (!calculate_sizes(s, -1)) |
|
goto error; |
|
if (disable_higher_order_debug) { |
|
/* |
|
* Disable debugging flags that store metadata if the min slab |
|
* order increased. |
|
*/ |
|
if (get_order(s->size) > get_order(s->object_size)) { |
|
s->flags &= ~DEBUG_METADATA_FLAGS; |
|
s->offset = 0; |
|
if (!calculate_sizes(s, -1)) |
|
goto error; |
|
} |
|
} |
|
|
|
#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
|
defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
|
if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0) |
|
/* Enable fast mode */ |
|
s->flags |= __CMPXCHG_DOUBLE; |
|
#endif |
|
|
|
/* |
|
* The larger the object size is, the more pages we want on the partial |
|
* list to avoid pounding the page allocator excessively. |
|
*/ |
|
set_min_partial(s, ilog2(s->size) / 2); |
|
|
|
set_cpu_partial(s); |
|
|
|
#ifdef CONFIG_NUMA |
|
s->remote_node_defrag_ratio = 1000; |
|
#endif |
|
|
|
/* Initialize the pre-computed randomized freelist if slab is up */ |
|
if (slab_state >= UP) { |
|
if (init_cache_random_seq(s)) |
|
goto error; |
|
} |
|
|
|
if (!init_kmem_cache_nodes(s)) |
|
goto error; |
|
|
|
if (alloc_kmem_cache_cpus(s)) |
|
return 0; |
|
|
|
free_kmem_cache_nodes(s); |
|
error: |
|
return -EINVAL; |
|
} |
|
|
|
static void list_slab_objects(struct kmem_cache *s, struct page *page, |
|
const char *text) |
|
{ |
|
#ifdef CONFIG_SLUB_DEBUG |
|
void *addr = page_address(page); |
|
unsigned long *map; |
|
void *p; |
|
|
|
slab_err(s, page, text, s->name); |
|
slab_lock(page); |
|
|
|
map = get_map(s, page); |
|
for_each_object(p, s, addr, page->objects) { |
|
|
|
if (!test_bit(__obj_to_index(s, addr, p), map)) { |
|
pr_err("Object 0x%p @offset=%tu\n", p, p - addr); |
|
print_tracking(s, p); |
|
} |
|
} |
|
put_map(map); |
|
slab_unlock(page); |
|
#endif |
|
} |
|
|
|
/* |
|
* Attempt to free all partial slabs on a node. |
|
* This is called from __kmem_cache_shutdown(). We must take list_lock |
|
* because sysfs file might still access partial list after the shutdowning. |
|
*/ |
|
static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) |
|
{ |
|
LIST_HEAD(discard); |
|
struct page *page, *h; |
|
|
|
BUG_ON(irqs_disabled()); |
|
spin_lock_irq(&n->list_lock); |
|
list_for_each_entry_safe(page, h, &n->partial, slab_list) { |
|
if (!page->inuse) { |
|
remove_partial(n, page); |
|
list_add(&page->slab_list, &discard); |
|
} else { |
|
list_slab_objects(s, page, |
|
"Objects remaining in %s on __kmem_cache_shutdown()"); |
|
} |
|
} |
|
spin_unlock_irq(&n->list_lock); |
|
|
|
list_for_each_entry_safe(page, h, &discard, slab_list) |
|
discard_slab(s, page); |
|
} |
|
|
|
bool __kmem_cache_empty(struct kmem_cache *s) |
|
{ |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) |
|
if (n->nr_partial || slabs_node(s, node)) |
|
return false; |
|
return true; |
|
} |
|
|
|
/* |
|
* Release all resources used by a slab cache. |
|
*/ |
|
int __kmem_cache_shutdown(struct kmem_cache *s) |
|
{ |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
flush_all(s); |
|
/* Attempt to free all objects */ |
|
for_each_kmem_cache_node(s, node, n) { |
|
free_partial(s, n); |
|
if (n->nr_partial || slabs_node(s, node)) |
|
return 1; |
|
} |
|
return 0; |
|
} |
|
|
|
#ifdef CONFIG_PRINTK |
|
void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) |
|
{ |
|
void *base; |
|
int __maybe_unused i; |
|
unsigned int objnr; |
|
void *objp; |
|
void *objp0; |
|
struct kmem_cache *s = page->slab_cache; |
|
struct track __maybe_unused *trackp; |
|
|
|
kpp->kp_ptr = object; |
|
kpp->kp_page = page; |
|
kpp->kp_slab_cache = s; |
|
base = page_address(page); |
|
objp0 = kasan_reset_tag(object); |
|
#ifdef CONFIG_SLUB_DEBUG |
|
objp = restore_red_left(s, objp0); |
|
#else |
|
objp = objp0; |
|
#endif |
|
objnr = obj_to_index(s, page, objp); |
|
kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp); |
|
objp = base + s->size * objnr; |
|
kpp->kp_objp = objp; |
|
if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) || |
|
!(s->flags & SLAB_STORE_USER)) |
|
return; |
|
#ifdef CONFIG_SLUB_DEBUG |
|
objp = fixup_red_left(s, objp); |
|
trackp = get_track(s, objp, TRACK_ALLOC); |
|
kpp->kp_ret = (void *)trackp->addr; |
|
#ifdef CONFIG_STACKTRACE |
|
for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) { |
|
kpp->kp_stack[i] = (void *)trackp->addrs[i]; |
|
if (!kpp->kp_stack[i]) |
|
break; |
|
} |
|
|
|
trackp = get_track(s, objp, TRACK_FREE); |
|
for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) { |
|
kpp->kp_free_stack[i] = (void *)trackp->addrs[i]; |
|
if (!kpp->kp_free_stack[i]) |
|
break; |
|
} |
|
#endif |
|
#endif |
|
} |
|
#endif |
|
|
|
/******************************************************************** |
|
* Kmalloc subsystem |
|
*******************************************************************/ |
|
|
|
static int __init setup_slub_min_order(char *str) |
|
{ |
|
get_option(&str, (int *)&slub_min_order); |
|
|
|
return 1; |
|
} |
|
|
|
__setup("slub_min_order=", setup_slub_min_order); |
|
|
|
static int __init setup_slub_max_order(char *str) |
|
{ |
|
get_option(&str, (int *)&slub_max_order); |
|
slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1); |
|
|
|
return 1; |
|
} |
|
|
|
__setup("slub_max_order=", setup_slub_max_order); |
|
|
|
static int __init setup_slub_min_objects(char *str) |
|
{ |
|
get_option(&str, (int *)&slub_min_objects); |
|
|
|
return 1; |
|
} |
|
|
|
__setup("slub_min_objects=", setup_slub_min_objects); |
|
|
|
void *__kmalloc(size_t size, gfp_t flags) |
|
{ |
|
struct kmem_cache *s; |
|
void *ret; |
|
|
|
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) |
|
return kmalloc_large(size, flags); |
|
|
|
s = kmalloc_slab(size, flags); |
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(s))) |
|
return s; |
|
|
|
ret = slab_alloc(s, flags, _RET_IP_, size); |
|
|
|
trace_kmalloc(_RET_IP_, ret, size, s->size, flags); |
|
|
|
ret = kasan_kmalloc(s, ret, size, flags); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(__kmalloc); |
|
|
|
#ifdef CONFIG_NUMA |
|
static void *kmalloc_large_node(size_t size, gfp_t flags, int node) |
|
{ |
|
struct page *page; |
|
void *ptr = NULL; |
|
unsigned int order = get_order(size); |
|
|
|
flags |= __GFP_COMP; |
|
page = alloc_pages_node(node, flags, order); |
|
if (page) { |
|
ptr = page_address(page); |
|
mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, |
|
PAGE_SIZE << order); |
|
} |
|
|
|
return kmalloc_large_node_hook(ptr, size, flags); |
|
} |
|
|
|
void *__kmalloc_node(size_t size, gfp_t flags, int node) |
|
{ |
|
struct kmem_cache *s; |
|
void *ret; |
|
|
|
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { |
|
ret = kmalloc_large_node(size, flags, node); |
|
|
|
trace_kmalloc_node(_RET_IP_, ret, |
|
size, PAGE_SIZE << get_order(size), |
|
flags, node); |
|
|
|
return ret; |
|
} |
|
|
|
s = kmalloc_slab(size, flags); |
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(s))) |
|
return s; |
|
|
|
ret = slab_alloc_node(s, flags, node, _RET_IP_, size); |
|
|
|
trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node); |
|
|
|
ret = kasan_kmalloc(s, ret, size, flags); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(__kmalloc_node); |
|
#endif /* CONFIG_NUMA */ |
|
|
|
#ifdef CONFIG_HARDENED_USERCOPY |
|
/* |
|
* Rejects incorrectly sized objects and objects that are to be copied |
|
* to/from userspace but do not fall entirely within the containing slab |
|
* cache's usercopy region. |
|
* |
|
* Returns NULL if check passes, otherwise const char * to name of cache |
|
* to indicate an error. |
|
*/ |
|
void __check_heap_object(const void *ptr, unsigned long n, struct page *page, |
|
bool to_user) |
|
{ |
|
struct kmem_cache *s; |
|
unsigned int offset; |
|
size_t object_size; |
|
bool is_kfence = is_kfence_address(ptr); |
|
|
|
ptr = kasan_reset_tag(ptr); |
|
|
|
/* Find object and usable object size. */ |
|
s = page->slab_cache; |
|
|
|
/* Reject impossible pointers. */ |
|
if (ptr < page_address(page)) |
|
usercopy_abort("SLUB object not in SLUB page?!", NULL, |
|
to_user, 0, n); |
|
|
|
/* Find offset within object. */ |
|
if (is_kfence) |
|
offset = ptr - kfence_object_start(ptr); |
|
else |
|
offset = (ptr - page_address(page)) % s->size; |
|
|
|
/* Adjust for redzone and reject if within the redzone. */ |
|
if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) { |
|
if (offset < s->red_left_pad) |
|
usercopy_abort("SLUB object in left red zone", |
|
s->name, to_user, offset, n); |
|
offset -= s->red_left_pad; |
|
} |
|
|
|
/* Allow address range falling entirely within usercopy region. */ |
|
if (offset >= s->useroffset && |
|
offset - s->useroffset <= s->usersize && |
|
n <= s->useroffset - offset + s->usersize) |
|
return; |
|
|
|
/* |
|
* If the copy is still within the allocated object, produce |
|
* a warning instead of rejecting the copy. This is intended |
|
* to be a temporary method to find any missing usercopy |
|
* whitelists. |
|
*/ |
|
object_size = slab_ksize(s); |
|
if (usercopy_fallback && |
|
offset <= object_size && n <= object_size - offset) { |
|
usercopy_warn("SLUB object", s->name, to_user, offset, n); |
|
return; |
|
} |
|
|
|
usercopy_abort("SLUB object", s->name, to_user, offset, n); |
|
} |
|
#endif /* CONFIG_HARDENED_USERCOPY */ |
|
|
|
size_t __ksize(const void *object) |
|
{ |
|
struct page *page; |
|
|
|
if (unlikely(object == ZERO_SIZE_PTR)) |
|
return 0; |
|
|
|
page = virt_to_head_page(object); |
|
|
|
if (unlikely(!PageSlab(page))) { |
|
WARN_ON(!PageCompound(page)); |
|
return page_size(page); |
|
} |
|
|
|
return slab_ksize(page->slab_cache); |
|
} |
|
EXPORT_SYMBOL(__ksize); |
|
|
|
void kfree(const void *x) |
|
{ |
|
struct page *page; |
|
void *object = (void *)x; |
|
|
|
trace_kfree(_RET_IP_, x); |
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(x))) |
|
return; |
|
|
|
page = virt_to_head_page(x); |
|
if (unlikely(!PageSlab(page))) { |
|
unsigned int order = compound_order(page); |
|
|
|
BUG_ON(!PageCompound(page)); |
|
kfree_hook(object); |
|
mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, |
|
-(PAGE_SIZE << order)); |
|
__free_pages(page, order); |
|
return; |
|
} |
|
slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_); |
|
} |
|
EXPORT_SYMBOL(kfree); |
|
|
|
#define SHRINK_PROMOTE_MAX 32 |
|
|
|
/* |
|
* kmem_cache_shrink discards empty slabs and promotes the slabs filled |
|
* up most to the head of the partial lists. New allocations will then |
|
* fill those up and thus they can be removed from the partial lists. |
|
* |
|
* The slabs with the least items are placed last. This results in them |
|
* being allocated from last increasing the chance that the last objects |
|
* are freed in them. |
|
*/ |
|
int __kmem_cache_shrink(struct kmem_cache *s) |
|
{ |
|
int node; |
|
int i; |
|
struct kmem_cache_node *n; |
|
struct page *page; |
|
struct page *t; |
|
struct list_head discard; |
|
struct list_head promote[SHRINK_PROMOTE_MAX]; |
|
unsigned long flags; |
|
int ret = 0; |
|
|
|
flush_all(s); |
|
for_each_kmem_cache_node(s, node, n) { |
|
INIT_LIST_HEAD(&discard); |
|
for (i = 0; i < SHRINK_PROMOTE_MAX; i++) |
|
INIT_LIST_HEAD(promote + i); |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
|
|
/* |
|
* Build lists of slabs to discard or promote. |
|
* |
|
* Note that concurrent frees may occur while we hold the |
|
* list_lock. page->inuse here is the upper limit. |
|
*/ |
|
list_for_each_entry_safe(page, t, &n->partial, slab_list) { |
|
int free = page->objects - page->inuse; |
|
|
|
/* Do not reread page->inuse */ |
|
barrier(); |
|
|
|
/* We do not keep full slabs on the list */ |
|
BUG_ON(free <= 0); |
|
|
|
if (free == page->objects) { |
|
list_move(&page->slab_list, &discard); |
|
n->nr_partial--; |
|
} else if (free <= SHRINK_PROMOTE_MAX) |
|
list_move(&page->slab_list, promote + free - 1); |
|
} |
|
|
|
/* |
|
* Promote the slabs filled up most to the head of the |
|
* partial list. |
|
*/ |
|
for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--) |
|
list_splice(promote + i, &n->partial); |
|
|
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
|
|
/* Release empty slabs */ |
|
list_for_each_entry_safe(page, t, &discard, slab_list) |
|
discard_slab(s, page); |
|
|
|
if (slabs_node(s, node)) |
|
ret = 1; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static int slab_mem_going_offline_callback(void *arg) |
|
{ |
|
struct kmem_cache *s; |
|
|
|
mutex_lock(&slab_mutex); |
|
list_for_each_entry(s, &slab_caches, list) |
|
__kmem_cache_shrink(s); |
|
mutex_unlock(&slab_mutex); |
|
|
|
return 0; |
|
} |
|
|
|
static void slab_mem_offline_callback(void *arg) |
|
{ |
|
struct memory_notify *marg = arg; |
|
int offline_node; |
|
|
|
offline_node = marg->status_change_nid_normal; |
|
|
|
/* |
|
* If the node still has available memory. we need kmem_cache_node |
|
* for it yet. |
|
*/ |
|
if (offline_node < 0) |
|
return; |
|
|
|
mutex_lock(&slab_mutex); |
|
node_clear(offline_node, slab_nodes); |
|
/* |
|
* We no longer free kmem_cache_node structures here, as it would be |
|
* racy with all get_node() users, and infeasible to protect them with |
|
* slab_mutex. |
|
*/ |
|
mutex_unlock(&slab_mutex); |
|
} |
|
|
|
static int slab_mem_going_online_callback(void *arg) |
|
{ |
|
struct kmem_cache_node *n; |
|
struct kmem_cache *s; |
|
struct memory_notify *marg = arg; |
|
int nid = marg->status_change_nid_normal; |
|
int ret = 0; |
|
|
|
/* |
|
* If the node's memory is already available, then kmem_cache_node is |
|
* already created. Nothing to do. |
|
*/ |
|
if (nid < 0) |
|
return 0; |
|
|
|
/* |
|
* We are bringing a node online. No memory is available yet. We must |
|
* allocate a kmem_cache_node structure in order to bring the node |
|
* online. |
|
*/ |
|
mutex_lock(&slab_mutex); |
|
list_for_each_entry(s, &slab_caches, list) { |
|
/* |
|
* The structure may already exist if the node was previously |
|
* onlined and offlined. |
|
*/ |
|
if (get_node(s, nid)) |
|
continue; |
|
/* |
|
* XXX: kmem_cache_alloc_node will fallback to other nodes |
|
* since memory is not yet available from the node that |
|
* is brought up. |
|
*/ |
|
n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL); |
|
if (!n) { |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
init_kmem_cache_node(n); |
|
s->node[nid] = n; |
|
} |
|
/* |
|
* Any cache created after this point will also have kmem_cache_node |
|
* initialized for the new node. |
|
*/ |
|
node_set(nid, slab_nodes); |
|
out: |
|
mutex_unlock(&slab_mutex); |
|
return ret; |
|
} |
|
|
|
static int slab_memory_callback(struct notifier_block *self, |
|
unsigned long action, void *arg) |
|
{ |
|
int ret = 0; |
|
|
|
switch (action) { |
|
case MEM_GOING_ONLINE: |
|
ret = slab_mem_going_online_callback(arg); |
|
break; |
|
case MEM_GOING_OFFLINE: |
|
ret = slab_mem_going_offline_callback(arg); |
|
break; |
|
case MEM_OFFLINE: |
|
case MEM_CANCEL_ONLINE: |
|
slab_mem_offline_callback(arg); |
|
break; |
|
case MEM_ONLINE: |
|
case MEM_CANCEL_OFFLINE: |
|
break; |
|
} |
|
if (ret) |
|
ret = notifier_from_errno(ret); |
|
else |
|
ret = NOTIFY_OK; |
|
return ret; |
|
} |
|
|
|
static struct notifier_block slab_memory_callback_nb = { |
|
.notifier_call = slab_memory_callback, |
|
.priority = SLAB_CALLBACK_PRI, |
|
}; |
|
|
|
/******************************************************************** |
|
* Basic setup of slabs |
|
*******************************************************************/ |
|
|
|
/* |
|
* Used for early kmem_cache structures that were allocated using |
|
* the page allocator. Allocate them properly then fix up the pointers |
|
* that may be pointing to the wrong kmem_cache structure. |
|
*/ |
|
|
|
static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache) |
|
{ |
|
int node; |
|
struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); |
|
struct kmem_cache_node *n; |
|
|
|
memcpy(s, static_cache, kmem_cache->object_size); |
|
|
|
/* |
|
* This runs very early, and only the boot processor is supposed to be |
|
* up. Even if it weren't true, IRQs are not up so we couldn't fire |
|
* IPIs around. |
|
*/ |
|
__flush_cpu_slab(s, smp_processor_id()); |
|
for_each_kmem_cache_node(s, node, n) { |
|
struct page *p; |
|
|
|
list_for_each_entry(p, &n->partial, slab_list) |
|
p->slab_cache = s; |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
list_for_each_entry(p, &n->full, slab_list) |
|
p->slab_cache = s; |
|
#endif |
|
} |
|
list_add(&s->list, &slab_caches); |
|
return s; |
|
} |
|
|
|
void __init kmem_cache_init(void) |
|
{ |
|
static __initdata struct kmem_cache boot_kmem_cache, |
|
boot_kmem_cache_node; |
|
int node; |
|
|
|
if (debug_guardpage_minorder()) |
|
slub_max_order = 0; |
|
|
|
/* Print slub debugging pointers without hashing */ |
|
if (__slub_debug_enabled()) |
|
no_hash_pointers_enable(NULL); |
|
|
|
kmem_cache_node = &boot_kmem_cache_node; |
|
kmem_cache = &boot_kmem_cache; |
|
|
|
/* |
|
* Initialize the nodemask for which we will allocate per node |
|
* structures. Here we don't need taking slab_mutex yet. |
|
*/ |
|
for_each_node_state(node, N_NORMAL_MEMORY) |
|
node_set(node, slab_nodes); |
|
|
|
create_boot_cache(kmem_cache_node, "kmem_cache_node", |
|
sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0); |
|
|
|
register_hotmemory_notifier(&slab_memory_callback_nb); |
|
|
|
/* Able to allocate the per node structures */ |
|
slab_state = PARTIAL; |
|
|
|
create_boot_cache(kmem_cache, "kmem_cache", |
|
offsetof(struct kmem_cache, node) + |
|
nr_node_ids * sizeof(struct kmem_cache_node *), |
|
SLAB_HWCACHE_ALIGN, 0, 0); |
|
|
|
kmem_cache = bootstrap(&boot_kmem_cache); |
|
kmem_cache_node = bootstrap(&boot_kmem_cache_node); |
|
|
|
/* Now we can use the kmem_cache to allocate kmalloc slabs */ |
|
setup_kmalloc_cache_index_table(); |
|
create_kmalloc_caches(0); |
|
|
|
/* Setup random freelists for each cache */ |
|
init_freelist_randomization(); |
|
|
|
cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL, |
|
slub_cpu_dead); |
|
|
|
pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n", |
|
cache_line_size(), |
|
slub_min_order, slub_max_order, slub_min_objects, |
|
nr_cpu_ids, nr_node_ids); |
|
} |
|
|
|
void __init kmem_cache_init_late(void) |
|
{ |
|
} |
|
|
|
struct kmem_cache * |
|
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align, |
|
slab_flags_t flags, void (*ctor)(void *)) |
|
{ |
|
struct kmem_cache *s; |
|
|
|
s = find_mergeable(size, align, flags, name, ctor); |
|
if (s) { |
|
s->refcount++; |
|
|
|
/* |
|
* Adjust the object sizes so that we clear |
|
* the complete object on kzalloc. |
|
*/ |
|
s->object_size = max(s->object_size, size); |
|
s->inuse = max(s->inuse, ALIGN(size, sizeof(void *))); |
|
|
|
if (sysfs_slab_alias(s, name)) { |
|
s->refcount--; |
|
s = NULL; |
|
} |
|
} |
|
|
|
return s; |
|
} |
|
|
|
int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags) |
|
{ |
|
int err; |
|
|
|
err = kmem_cache_open(s, flags); |
|
if (err) |
|
return err; |
|
|
|
/* Mutex is not taken during early boot */ |
|
if (slab_state <= UP) |
|
return 0; |
|
|
|
err = sysfs_slab_add(s); |
|
if (err) |
|
__kmem_cache_release(s); |
|
|
|
if (s->flags & SLAB_STORE_USER) |
|
debugfs_slab_add(s); |
|
|
|
return err; |
|
} |
|
|
|
void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) |
|
{ |
|
struct kmem_cache *s; |
|
void *ret; |
|
|
|
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) |
|
return kmalloc_large(size, gfpflags); |
|
|
|
s = kmalloc_slab(size, gfpflags); |
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(s))) |
|
return s; |
|
|
|
ret = slab_alloc(s, gfpflags, caller, size); |
|
|
|
/* Honor the call site pointer we received. */ |
|
trace_kmalloc(caller, ret, size, s->size, gfpflags); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(__kmalloc_track_caller); |
|
|
|
#ifdef CONFIG_NUMA |
|
void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, |
|
int node, unsigned long caller) |
|
{ |
|
struct kmem_cache *s; |
|
void *ret; |
|
|
|
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { |
|
ret = kmalloc_large_node(size, gfpflags, node); |
|
|
|
trace_kmalloc_node(caller, ret, |
|
size, PAGE_SIZE << get_order(size), |
|
gfpflags, node); |
|
|
|
return ret; |
|
} |
|
|
|
s = kmalloc_slab(size, gfpflags); |
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(s))) |
|
return s; |
|
|
|
ret = slab_alloc_node(s, gfpflags, node, caller, size); |
|
|
|
/* Honor the call site pointer we received. */ |
|
trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(__kmalloc_node_track_caller); |
|
#endif |
|
|
|
#ifdef CONFIG_SYSFS |
|
static int count_inuse(struct page *page) |
|
{ |
|
return page->inuse; |
|
} |
|
|
|
static int count_total(struct page *page) |
|
{ |
|
return page->objects; |
|
} |
|
#endif |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
static void validate_slab(struct kmem_cache *s, struct page *page) |
|
{ |
|
void *p; |
|
void *addr = page_address(page); |
|
unsigned long *map; |
|
|
|
slab_lock(page); |
|
|
|
if (!check_slab(s, page) || !on_freelist(s, page, NULL)) |
|
goto unlock; |
|
|
|
/* Now we know that a valid freelist exists */ |
|
map = get_map(s, page); |
|
for_each_object(p, s, addr, page->objects) { |
|
u8 val = test_bit(__obj_to_index(s, addr, p), map) ? |
|
SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; |
|
|
|
if (!check_object(s, page, p, val)) |
|
break; |
|
} |
|
put_map(map); |
|
unlock: |
|
slab_unlock(page); |
|
} |
|
|
|
static int validate_slab_node(struct kmem_cache *s, |
|
struct kmem_cache_node *n) |
|
{ |
|
unsigned long count = 0; |
|
struct page *page; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
|
|
list_for_each_entry(page, &n->partial, slab_list) { |
|
validate_slab(s, page); |
|
count++; |
|
} |
|
if (count != n->nr_partial) { |
|
pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n", |
|
s->name, count, n->nr_partial); |
|
slab_add_kunit_errors(); |
|
} |
|
|
|
if (!(s->flags & SLAB_STORE_USER)) |
|
goto out; |
|
|
|
list_for_each_entry(page, &n->full, slab_list) { |
|
validate_slab(s, page); |
|
count++; |
|
} |
|
if (count != atomic_long_read(&n->nr_slabs)) { |
|
pr_err("SLUB: %s %ld slabs counted but counter=%ld\n", |
|
s->name, count, atomic_long_read(&n->nr_slabs)); |
|
slab_add_kunit_errors(); |
|
} |
|
|
|
out: |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
return count; |
|
} |
|
|
|
long validate_slab_cache(struct kmem_cache *s) |
|
{ |
|
int node; |
|
unsigned long count = 0; |
|
struct kmem_cache_node *n; |
|
|
|
flush_all(s); |
|
for_each_kmem_cache_node(s, node, n) |
|
count += validate_slab_node(s, n); |
|
|
|
return count; |
|
} |
|
EXPORT_SYMBOL(validate_slab_cache); |
|
|
|
#ifdef CONFIG_DEBUG_FS |
|
/* |
|
* Generate lists of code addresses where slabcache objects are allocated |
|
* and freed. |
|
*/ |
|
|
|
struct location { |
|
unsigned long count; |
|
unsigned long addr; |
|
long long sum_time; |
|
long min_time; |
|
long max_time; |
|
long min_pid; |
|
long max_pid; |
|
DECLARE_BITMAP(cpus, NR_CPUS); |
|
nodemask_t nodes; |
|
}; |
|
|
|
struct loc_track { |
|
unsigned long max; |
|
unsigned long count; |
|
struct location *loc; |
|
}; |
|
|
|
static struct dentry *slab_debugfs_root; |
|
|
|
static void free_loc_track(struct loc_track *t) |
|
{ |
|
if (t->max) |
|
free_pages((unsigned long)t->loc, |
|
get_order(sizeof(struct location) * t->max)); |
|
} |
|
|
|
static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags) |
|
{ |
|
struct location *l; |
|
int order; |
|
|
|
order = get_order(sizeof(struct location) * max); |
|
|
|
l = (void *)__get_free_pages(flags, order); |
|
if (!l) |
|
return 0; |
|
|
|
if (t->count) { |
|
memcpy(l, t->loc, sizeof(struct location) * t->count); |
|
free_loc_track(t); |
|
} |
|
t->max = max; |
|
t->loc = l; |
|
return 1; |
|
} |
|
|
|
static int add_location(struct loc_track *t, struct kmem_cache *s, |
|
const struct track *track) |
|
{ |
|
long start, end, pos; |
|
struct location *l; |
|
unsigned long caddr; |
|
unsigned long age = jiffies - track->when; |
|
|
|
start = -1; |
|
end = t->count; |
|
|
|
for ( ; ; ) { |
|
pos = start + (end - start + 1) / 2; |
|
|
|
/* |
|
* There is nothing at "end". If we end up there |
|
* we need to add something to before end. |
|
*/ |
|
if (pos == end) |
|
break; |
|
|
|
caddr = t->loc[pos].addr; |
|
if (track->addr == caddr) { |
|
|
|
l = &t->loc[pos]; |
|
l->count++; |
|
if (track->when) { |
|
l->sum_time += age; |
|
if (age < l->min_time) |
|
l->min_time = age; |
|
if (age > l->max_time) |
|
l->max_time = age; |
|
|
|
if (track->pid < l->min_pid) |
|
l->min_pid = track->pid; |
|
if (track->pid > l->max_pid) |
|
l->max_pid = track->pid; |
|
|
|
cpumask_set_cpu(track->cpu, |
|
to_cpumask(l->cpus)); |
|
} |
|
node_set(page_to_nid(virt_to_page(track)), l->nodes); |
|
return 1; |
|
} |
|
|
|
if (track->addr < caddr) |
|
end = pos; |
|
else |
|
start = pos; |
|
} |
|
|
|
/* |
|
* Not found. Insert new tracking element. |
|
*/ |
|
if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC)) |
|
return 0; |
|
|
|
l = t->loc + pos; |
|
if (pos < t->count) |
|
memmove(l + 1, l, |
|
(t->count - pos) * sizeof(struct location)); |
|
t->count++; |
|
l->count = 1; |
|
l->addr = track->addr; |
|
l->sum_time = age; |
|
l->min_time = age; |
|
l->max_time = age; |
|
l->min_pid = track->pid; |
|
l->max_pid = track->pid; |
|
cpumask_clear(to_cpumask(l->cpus)); |
|
cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); |
|
nodes_clear(l->nodes); |
|
node_set(page_to_nid(virt_to_page(track)), l->nodes); |
|
return 1; |
|
} |
|
|
|
static void process_slab(struct loc_track *t, struct kmem_cache *s, |
|
struct page *page, enum track_item alloc) |
|
{ |
|
void *addr = page_address(page); |
|
void *p; |
|
unsigned long *map; |
|
|
|
map = get_map(s, page); |
|
for_each_object(p, s, addr, page->objects) |
|
if (!test_bit(__obj_to_index(s, addr, p), map)) |
|
add_location(t, s, get_track(s, p, alloc)); |
|
put_map(map); |
|
} |
|
#endif /* CONFIG_DEBUG_FS */ |
|
#endif /* CONFIG_SLUB_DEBUG */ |
|
|
|
#ifdef CONFIG_SYSFS |
|
enum slab_stat_type { |
|
SL_ALL, /* All slabs */ |
|
SL_PARTIAL, /* Only partially allocated slabs */ |
|
SL_CPU, /* Only slabs used for cpu caches */ |
|
SL_OBJECTS, /* Determine allocated objects not slabs */ |
|
SL_TOTAL /* Determine object capacity not slabs */ |
|
}; |
|
|
|
#define SO_ALL (1 << SL_ALL) |
|
#define SO_PARTIAL (1 << SL_PARTIAL) |
|
#define SO_CPU (1 << SL_CPU) |
|
#define SO_OBJECTS (1 << SL_OBJECTS) |
|
#define SO_TOTAL (1 << SL_TOTAL) |
|
|
|
static ssize_t show_slab_objects(struct kmem_cache *s, |
|
char *buf, unsigned long flags) |
|
{ |
|
unsigned long total = 0; |
|
int node; |
|
int x; |
|
unsigned long *nodes; |
|
int len = 0; |
|
|
|
nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL); |
|
if (!nodes) |
|
return -ENOMEM; |
|
|
|
if (flags & SO_CPU) { |
|
int cpu; |
|
|
|
for_each_possible_cpu(cpu) { |
|
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, |
|
cpu); |
|
int node; |
|
struct page *page; |
|
|
|
page = READ_ONCE(c->page); |
|
if (!page) |
|
continue; |
|
|
|
node = page_to_nid(page); |
|
if (flags & SO_TOTAL) |
|
x = page->objects; |
|
else if (flags & SO_OBJECTS) |
|
x = page->inuse; |
|
else |
|
x = 1; |
|
|
|
total += x; |
|
nodes[node] += x; |
|
|
|
page = slub_percpu_partial_read_once(c); |
|
if (page) { |
|
node = page_to_nid(page); |
|
if (flags & SO_TOTAL) |
|
WARN_ON_ONCE(1); |
|
else if (flags & SO_OBJECTS) |
|
WARN_ON_ONCE(1); |
|
else |
|
x = page->pages; |
|
total += x; |
|
nodes[node] += x; |
|
} |
|
} |
|
} |
|
|
|
/* |
|
* It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex" |
|
* already held which will conflict with an existing lock order: |
|
* |
|
* mem_hotplug_lock->slab_mutex->kernfs_mutex |
|
* |
|
* We don't really need mem_hotplug_lock (to hold off |
|
* slab_mem_going_offline_callback) here because slab's memory hot |
|
* unplug code doesn't destroy the kmem_cache->node[] data. |
|
*/ |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
if (flags & SO_ALL) { |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
|
|
if (flags & SO_TOTAL) |
|
x = atomic_long_read(&n->total_objects); |
|
else if (flags & SO_OBJECTS) |
|
x = atomic_long_read(&n->total_objects) - |
|
count_partial(n, count_free); |
|
else |
|
x = atomic_long_read(&n->nr_slabs); |
|
total += x; |
|
nodes[node] += x; |
|
} |
|
|
|
} else |
|
#endif |
|
if (flags & SO_PARTIAL) { |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
if (flags & SO_TOTAL) |
|
x = count_partial(n, count_total); |
|
else if (flags & SO_OBJECTS) |
|
x = count_partial(n, count_inuse); |
|
else |
|
x = n->nr_partial; |
|
total += x; |
|
nodes[node] += x; |
|
} |
|
} |
|
|
|
len += sysfs_emit_at(buf, len, "%lu", total); |
|
#ifdef CONFIG_NUMA |
|
for (node = 0; node < nr_node_ids; node++) { |
|
if (nodes[node]) |
|
len += sysfs_emit_at(buf, len, " N%d=%lu", |
|
node, nodes[node]); |
|
} |
|
#endif |
|
len += sysfs_emit_at(buf, len, "\n"); |
|
kfree(nodes); |
|
|
|
return len; |
|
} |
|
|
|
#define to_slab_attr(n) container_of(n, struct slab_attribute, attr) |
|
#define to_slab(n) container_of(n, struct kmem_cache, kobj) |
|
|
|
struct slab_attribute { |
|
struct attribute attr; |
|
ssize_t (*show)(struct kmem_cache *s, char *buf); |
|
ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); |
|
}; |
|
|
|
#define SLAB_ATTR_RO(_name) \ |
|
static struct slab_attribute _name##_attr = \ |
|
__ATTR(_name, 0400, _name##_show, NULL) |
|
|
|
#define SLAB_ATTR(_name) \ |
|
static struct slab_attribute _name##_attr = \ |
|
__ATTR(_name, 0600, _name##_show, _name##_store) |
|
|
|
static ssize_t slab_size_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", s->size); |
|
} |
|
SLAB_ATTR_RO(slab_size); |
|
|
|
static ssize_t align_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", s->align); |
|
} |
|
SLAB_ATTR_RO(align); |
|
|
|
static ssize_t object_size_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", s->object_size); |
|
} |
|
SLAB_ATTR_RO(object_size); |
|
|
|
static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", oo_objects(s->oo)); |
|
} |
|
SLAB_ATTR_RO(objs_per_slab); |
|
|
|
static ssize_t order_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", oo_order(s->oo)); |
|
} |
|
SLAB_ATTR_RO(order); |
|
|
|
static ssize_t min_partial_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%lu\n", s->min_partial); |
|
} |
|
|
|
static ssize_t min_partial_store(struct kmem_cache *s, const char *buf, |
|
size_t length) |
|
{ |
|
unsigned long min; |
|
int err; |
|
|
|
err = kstrtoul(buf, 10, &min); |
|
if (err) |
|
return err; |
|
|
|
set_min_partial(s, min); |
|
return length; |
|
} |
|
SLAB_ATTR(min_partial); |
|
|
|
static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", slub_cpu_partial(s)); |
|
} |
|
|
|
static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf, |
|
size_t length) |
|
{ |
|
unsigned int objects; |
|
int err; |
|
|
|
err = kstrtouint(buf, 10, &objects); |
|
if (err) |
|
return err; |
|
if (objects && !kmem_cache_has_cpu_partial(s)) |
|
return -EINVAL; |
|
|
|
slub_set_cpu_partial(s, objects); |
|
flush_all(s); |
|
return length; |
|
} |
|
SLAB_ATTR(cpu_partial); |
|
|
|
static ssize_t ctor_show(struct kmem_cache *s, char *buf) |
|
{ |
|
if (!s->ctor) |
|
return 0; |
|
return sysfs_emit(buf, "%pS\n", s->ctor); |
|
} |
|
SLAB_ATTR_RO(ctor); |
|
|
|
static ssize_t aliases_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1); |
|
} |
|
SLAB_ATTR_RO(aliases); |
|
|
|
static ssize_t partial_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_PARTIAL); |
|
} |
|
SLAB_ATTR_RO(partial); |
|
|
|
static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_CPU); |
|
} |
|
SLAB_ATTR_RO(cpu_slabs); |
|
|
|
static ssize_t objects_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS); |
|
} |
|
SLAB_ATTR_RO(objects); |
|
|
|
static ssize_t objects_partial_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS); |
|
} |
|
SLAB_ATTR_RO(objects_partial); |
|
|
|
static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) |
|
{ |
|
int objects = 0; |
|
int pages = 0; |
|
int cpu; |
|
int len = 0; |
|
|
|
for_each_online_cpu(cpu) { |
|
struct page *page; |
|
|
|
page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu)); |
|
|
|
if (page) { |
|
pages += page->pages; |
|
objects += page->pobjects; |
|
} |
|
} |
|
|
|
len += sysfs_emit_at(buf, len, "%d(%d)", objects, pages); |
|
|
|
#ifdef CONFIG_SMP |
|
for_each_online_cpu(cpu) { |
|
struct page *page; |
|
|
|
page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu)); |
|
if (page) |
|
len += sysfs_emit_at(buf, len, " C%d=%d(%d)", |
|
cpu, page->pobjects, page->pages); |
|
} |
|
#endif |
|
len += sysfs_emit_at(buf, len, "\n"); |
|
|
|
return len; |
|
} |
|
SLAB_ATTR_RO(slabs_cpu_partial); |
|
|
|
static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); |
|
} |
|
SLAB_ATTR_RO(reclaim_account); |
|
|
|
static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN)); |
|
} |
|
SLAB_ATTR_RO(hwcache_align); |
|
|
|
#ifdef CONFIG_ZONE_DMA |
|
static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); |
|
} |
|
SLAB_ATTR_RO(cache_dma); |
|
#endif |
|
|
|
static ssize_t usersize_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", s->usersize); |
|
} |
|
SLAB_ATTR_RO(usersize); |
|
|
|
static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU)); |
|
} |
|
SLAB_ATTR_RO(destroy_by_rcu); |
|
|
|
#ifdef CONFIG_SLUB_DEBUG |
|
static ssize_t slabs_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_ALL); |
|
} |
|
SLAB_ATTR_RO(slabs); |
|
|
|
static ssize_t total_objects_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return show_slab_objects(s, buf, SO_ALL|SO_TOTAL); |
|
} |
|
SLAB_ATTR_RO(total_objects); |
|
|
|
static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS)); |
|
} |
|
SLAB_ATTR_RO(sanity_checks); |
|
|
|
static ssize_t trace_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE)); |
|
} |
|
SLAB_ATTR_RO(trace); |
|
|
|
static ssize_t red_zone_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); |
|
} |
|
|
|
SLAB_ATTR_RO(red_zone); |
|
|
|
static ssize_t poison_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON)); |
|
} |
|
|
|
SLAB_ATTR_RO(poison); |
|
|
|
static ssize_t store_user_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); |
|
} |
|
|
|
SLAB_ATTR_RO(store_user); |
|
|
|
static ssize_t validate_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return 0; |
|
} |
|
|
|
static ssize_t validate_store(struct kmem_cache *s, |
|
const char *buf, size_t length) |
|
{ |
|
int ret = -EINVAL; |
|
|
|
if (buf[0] == '1') { |
|
ret = validate_slab_cache(s); |
|
if (ret >= 0) |
|
ret = length; |
|
} |
|
return ret; |
|
} |
|
SLAB_ATTR(validate); |
|
|
|
#endif /* CONFIG_SLUB_DEBUG */ |
|
|
|
#ifdef CONFIG_FAILSLAB |
|
static ssize_t failslab_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB)); |
|
} |
|
SLAB_ATTR_RO(failslab); |
|
#endif |
|
|
|
static ssize_t shrink_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return 0; |
|
} |
|
|
|
static ssize_t shrink_store(struct kmem_cache *s, |
|
const char *buf, size_t length) |
|
{ |
|
if (buf[0] == '1') |
|
kmem_cache_shrink(s); |
|
else |
|
return -EINVAL; |
|
return length; |
|
} |
|
SLAB_ATTR(shrink); |
|
|
|
#ifdef CONFIG_NUMA |
|
static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf) |
|
{ |
|
return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10); |
|
} |
|
|
|
static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s, |
|
const char *buf, size_t length) |
|
{ |
|
unsigned int ratio; |
|
int err; |
|
|
|
err = kstrtouint(buf, 10, &ratio); |
|
if (err) |
|
return err; |
|
if (ratio > 100) |
|
return -ERANGE; |
|
|
|
s->remote_node_defrag_ratio = ratio * 10; |
|
|
|
return length; |
|
} |
|
SLAB_ATTR(remote_node_defrag_ratio); |
|
#endif |
|
|
|
#ifdef CONFIG_SLUB_STATS |
|
static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si) |
|
{ |
|
unsigned long sum = 0; |
|
int cpu; |
|
int len = 0; |
|
int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL); |
|
|
|
if (!data) |
|
return -ENOMEM; |
|
|
|
for_each_online_cpu(cpu) { |
|
unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si]; |
|
|
|
data[cpu] = x; |
|
sum += x; |
|
} |
|
|
|
len += sysfs_emit_at(buf, len, "%lu", sum); |
|
|
|
#ifdef CONFIG_SMP |
|
for_each_online_cpu(cpu) { |
|
if (data[cpu]) |
|
len += sysfs_emit_at(buf, len, " C%d=%u", |
|
cpu, data[cpu]); |
|
} |
|
#endif |
|
kfree(data); |
|
len += sysfs_emit_at(buf, len, "\n"); |
|
|
|
return len; |
|
} |
|
|
|
static void clear_stat(struct kmem_cache *s, enum stat_item si) |
|
{ |
|
int cpu; |
|
|
|
for_each_online_cpu(cpu) |
|
per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0; |
|
} |
|
|
|
#define STAT_ATTR(si, text) \ |
|
static ssize_t text##_show(struct kmem_cache *s, char *buf) \ |
|
{ \ |
|
return show_stat(s, buf, si); \ |
|
} \ |
|
static ssize_t text##_store(struct kmem_cache *s, \ |
|
const char *buf, size_t length) \ |
|
{ \ |
|
if (buf[0] != '0') \ |
|
return -EINVAL; \ |
|
clear_stat(s, si); \ |
|
return length; \ |
|
} \ |
|
SLAB_ATTR(text); \ |
|
|
|
STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath); |
|
STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath); |
|
STAT_ATTR(FREE_FASTPATH, free_fastpath); |
|
STAT_ATTR(FREE_SLOWPATH, free_slowpath); |
|
STAT_ATTR(FREE_FROZEN, free_frozen); |
|
STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial); |
|
STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial); |
|
STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial); |
|
STAT_ATTR(ALLOC_SLAB, alloc_slab); |
|
STAT_ATTR(ALLOC_REFILL, alloc_refill); |
|
STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch); |
|
STAT_ATTR(FREE_SLAB, free_slab); |
|
STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush); |
|
STAT_ATTR(DEACTIVATE_FULL, deactivate_full); |
|
STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty); |
|
STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head); |
|
STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail); |
|
STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees); |
|
STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass); |
|
STAT_ATTR(ORDER_FALLBACK, order_fallback); |
|
STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail); |
|
STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail); |
|
STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc); |
|
STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free); |
|
STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node); |
|
STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain); |
|
#endif /* CONFIG_SLUB_STATS */ |
|
|
|
static struct attribute *slab_attrs[] = { |
|
&slab_size_attr.attr, |
|
&object_size_attr.attr, |
|
&objs_per_slab_attr.attr, |
|
&order_attr.attr, |
|
&min_partial_attr.attr, |
|
&cpu_partial_attr.attr, |
|
&objects_attr.attr, |
|
&objects_partial_attr.attr, |
|
&partial_attr.attr, |
|
&cpu_slabs_attr.attr, |
|
&ctor_attr.attr, |
|
&aliases_attr.attr, |
|
&align_attr.attr, |
|
&hwcache_align_attr.attr, |
|
&reclaim_account_attr.attr, |
|
&destroy_by_rcu_attr.attr, |
|
&shrink_attr.attr, |
|
&slabs_cpu_partial_attr.attr, |
|
#ifdef CONFIG_SLUB_DEBUG |
|
&total_objects_attr.attr, |
|
&slabs_attr.attr, |
|
&sanity_checks_attr.attr, |
|
&trace_attr.attr, |
|
&red_zone_attr.attr, |
|
&poison_attr.attr, |
|
&store_user_attr.attr, |
|
&validate_attr.attr, |
|
#endif |
|
#ifdef CONFIG_ZONE_DMA |
|
&cache_dma_attr.attr, |
|
#endif |
|
#ifdef CONFIG_NUMA |
|
&remote_node_defrag_ratio_attr.attr, |
|
#endif |
|
#ifdef CONFIG_SLUB_STATS |
|
&alloc_fastpath_attr.attr, |
|
&alloc_slowpath_attr.attr, |
|
&free_fastpath_attr.attr, |
|
&free_slowpath_attr.attr, |
|
&free_frozen_attr.attr, |
|
&free_add_partial_attr.attr, |
|
&free_remove_partial_attr.attr, |
|
&alloc_from_partial_attr.attr, |
|
&alloc_slab_attr.attr, |
|
&alloc_refill_attr.attr, |
|
&alloc_node_mismatch_attr.attr, |
|
&free_slab_attr.attr, |
|
&cpuslab_flush_attr.attr, |
|
&deactivate_full_attr.attr, |
|
&deactivate_empty_attr.attr, |
|
&deactivate_to_head_attr.attr, |
|
&deactivate_to_tail_attr.attr, |
|
&deactivate_remote_frees_attr.attr, |
|
&deactivate_bypass_attr.attr, |
|
&order_fallback_attr.attr, |
|
&cmpxchg_double_fail_attr.attr, |
|
&cmpxchg_double_cpu_fail_attr.attr, |
|
&cpu_partial_alloc_attr.attr, |
|
&cpu_partial_free_attr.attr, |
|
&cpu_partial_node_attr.attr, |
|
&cpu_partial_drain_attr.attr, |
|
#endif |
|
#ifdef CONFIG_FAILSLAB |
|
&failslab_attr.attr, |
|
#endif |
|
&usersize_attr.attr, |
|
|
|
NULL |
|
}; |
|
|
|
static const struct attribute_group slab_attr_group = { |
|
.attrs = slab_attrs, |
|
}; |
|
|
|
static ssize_t slab_attr_show(struct kobject *kobj, |
|
struct attribute *attr, |
|
char *buf) |
|
{ |
|
struct slab_attribute *attribute; |
|
struct kmem_cache *s; |
|
int err; |
|
|
|
attribute = to_slab_attr(attr); |
|
s = to_slab(kobj); |
|
|
|
if (!attribute->show) |
|
return -EIO; |
|
|
|
err = attribute->show(s, buf); |
|
|
|
return err; |
|
} |
|
|
|
static ssize_t slab_attr_store(struct kobject *kobj, |
|
struct attribute *attr, |
|
const char *buf, size_t len) |
|
{ |
|
struct slab_attribute *attribute; |
|
struct kmem_cache *s; |
|
int err; |
|
|
|
attribute = to_slab_attr(attr); |
|
s = to_slab(kobj); |
|
|
|
if (!attribute->store) |
|
return -EIO; |
|
|
|
err = attribute->store(s, buf, len); |
|
return err; |
|
} |
|
|
|
static void kmem_cache_release(struct kobject *k) |
|
{ |
|
slab_kmem_cache_release(to_slab(k)); |
|
} |
|
|
|
static const struct sysfs_ops slab_sysfs_ops = { |
|
.show = slab_attr_show, |
|
.store = slab_attr_store, |
|
}; |
|
|
|
static struct kobj_type slab_ktype = { |
|
.sysfs_ops = &slab_sysfs_ops, |
|
.release = kmem_cache_release, |
|
}; |
|
|
|
static struct kset *slab_kset; |
|
|
|
static inline struct kset *cache_kset(struct kmem_cache *s) |
|
{ |
|
return slab_kset; |
|
} |
|
|
|
#define ID_STR_LENGTH 64 |
|
|
|
/* Create a unique string id for a slab cache: |
|
* |
|
* Format :[flags-]size |
|
*/ |
|
static char *create_unique_id(struct kmem_cache *s) |
|
{ |
|
char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); |
|
char *p = name; |
|
|
|
BUG_ON(!name); |
|
|
|
*p++ = ':'; |
|
/* |
|
* First flags affecting slabcache operations. We will only |
|
* get here for aliasable slabs so we do not need to support |
|
* too many flags. The flags here must cover all flags that |
|
* are matched during merging to guarantee that the id is |
|
* unique. |
|
*/ |
|
if (s->flags & SLAB_CACHE_DMA) |
|
*p++ = 'd'; |
|
if (s->flags & SLAB_CACHE_DMA32) |
|
*p++ = 'D'; |
|
if (s->flags & SLAB_RECLAIM_ACCOUNT) |
|
*p++ = 'a'; |
|
if (s->flags & SLAB_CONSISTENCY_CHECKS) |
|
*p++ = 'F'; |
|
if (s->flags & SLAB_ACCOUNT) |
|
*p++ = 'A'; |
|
if (p != name + 1) |
|
*p++ = '-'; |
|
p += sprintf(p, "%07u", s->size); |
|
|
|
BUG_ON(p > name + ID_STR_LENGTH - 1); |
|
return name; |
|
} |
|
|
|
static int sysfs_slab_add(struct kmem_cache *s) |
|
{ |
|
int err; |
|
const char *name; |
|
struct kset *kset = cache_kset(s); |
|
int unmergeable = slab_unmergeable(s); |
|
|
|
if (!kset) { |
|
kobject_init(&s->kobj, &slab_ktype); |
|
return 0; |
|
} |
|
|
|
if (!unmergeable && disable_higher_order_debug && |
|
(slub_debug & DEBUG_METADATA_FLAGS)) |
|
unmergeable = 1; |
|
|
|
if (unmergeable) { |
|
/* |
|
* Slabcache can never be merged so we can use the name proper. |
|
* This is typically the case for debug situations. In that |
|
* case we can catch duplicate names easily. |
|
*/ |
|
sysfs_remove_link(&slab_kset->kobj, s->name); |
|
name = s->name; |
|
} else { |
|
/* |
|
* Create a unique name for the slab as a target |
|
* for the symlinks. |
|
*/ |
|
name = create_unique_id(s); |
|
} |
|
|
|
s->kobj.kset = kset; |
|
err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); |
|
if (err) |
|
goto out; |
|
|
|
err = sysfs_create_group(&s->kobj, &slab_attr_group); |
|
if (err) |
|
goto out_del_kobj; |
|
|
|
if (!unmergeable) { |
|
/* Setup first alias */ |
|
sysfs_slab_alias(s, s->name); |
|
} |
|
out: |
|
if (!unmergeable) |
|
kfree(name); |
|
return err; |
|
out_del_kobj: |
|
kobject_del(&s->kobj); |
|
goto out; |
|
} |
|
|
|
void sysfs_slab_unlink(struct kmem_cache *s) |
|
{ |
|
if (slab_state >= FULL) |
|
kobject_del(&s->kobj); |
|
} |
|
|
|
void sysfs_slab_release(struct kmem_cache *s) |
|
{ |
|
if (slab_state >= FULL) |
|
kobject_put(&s->kobj); |
|
} |
|
|
|
/* |
|
* Need to buffer aliases during bootup until sysfs becomes |
|
* available lest we lose that information. |
|
*/ |
|
struct saved_alias { |
|
struct kmem_cache *s; |
|
const char *name; |
|
struct saved_alias *next; |
|
}; |
|
|
|
static struct saved_alias *alias_list; |
|
|
|
static int sysfs_slab_alias(struct kmem_cache *s, const char *name) |
|
{ |
|
struct saved_alias *al; |
|
|
|
if (slab_state == FULL) { |
|
/* |
|
* If we have a leftover link then remove it. |
|
*/ |
|
sysfs_remove_link(&slab_kset->kobj, name); |
|
return sysfs_create_link(&slab_kset->kobj, &s->kobj, name); |
|
} |
|
|
|
al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); |
|
if (!al) |
|
return -ENOMEM; |
|
|
|
al->s = s; |
|
al->name = name; |
|
al->next = alias_list; |
|
alias_list = al; |
|
return 0; |
|
} |
|
|
|
static int __init slab_sysfs_init(void) |
|
{ |
|
struct kmem_cache *s; |
|
int err; |
|
|
|
mutex_lock(&slab_mutex); |
|
|
|
slab_kset = kset_create_and_add("slab", NULL, kernel_kobj); |
|
if (!slab_kset) { |
|
mutex_unlock(&slab_mutex); |
|
pr_err("Cannot register slab subsystem.\n"); |
|
return -ENOSYS; |
|
} |
|
|
|
slab_state = FULL; |
|
|
|
list_for_each_entry(s, &slab_caches, list) { |
|
err = sysfs_slab_add(s); |
|
if (err) |
|
pr_err("SLUB: Unable to add boot slab %s to sysfs\n", |
|
s->name); |
|
} |
|
|
|
while (alias_list) { |
|
struct saved_alias *al = alias_list; |
|
|
|
alias_list = alias_list->next; |
|
err = sysfs_slab_alias(al->s, al->name); |
|
if (err) |
|
pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n", |
|
al->name); |
|
kfree(al); |
|
} |
|
|
|
mutex_unlock(&slab_mutex); |
|
return 0; |
|
} |
|
|
|
__initcall(slab_sysfs_init); |
|
#endif /* CONFIG_SYSFS */ |
|
|
|
#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS) |
|
static int slab_debugfs_show(struct seq_file *seq, void *v) |
|
{ |
|
|
|
struct location *l; |
|
unsigned int idx = *(unsigned int *)v; |
|
struct loc_track *t = seq->private; |
|
|
|
if (idx < t->count) { |
|
l = &t->loc[idx]; |
|
|
|
seq_printf(seq, "%7ld ", l->count); |
|
|
|
if (l->addr) |
|
seq_printf(seq, "%pS", (void *)l->addr); |
|
else |
|
seq_puts(seq, "<not-available>"); |
|
|
|
if (l->sum_time != l->min_time) { |
|
seq_printf(seq, " age=%ld/%llu/%ld", |
|
l->min_time, div_u64(l->sum_time, l->count), |
|
l->max_time); |
|
} else |
|
seq_printf(seq, " age=%ld", l->min_time); |
|
|
|
if (l->min_pid != l->max_pid) |
|
seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid); |
|
else |
|
seq_printf(seq, " pid=%ld", |
|
l->min_pid); |
|
|
|
if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus))) |
|
seq_printf(seq, " cpus=%*pbl", |
|
cpumask_pr_args(to_cpumask(l->cpus))); |
|
|
|
if (nr_online_nodes > 1 && !nodes_empty(l->nodes)) |
|
seq_printf(seq, " nodes=%*pbl", |
|
nodemask_pr_args(&l->nodes)); |
|
|
|
seq_puts(seq, "\n"); |
|
} |
|
|
|
if (!idx && !t->count) |
|
seq_puts(seq, "No data\n"); |
|
|
|
return 0; |
|
} |
|
|
|
static void slab_debugfs_stop(struct seq_file *seq, void *v) |
|
{ |
|
} |
|
|
|
static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos) |
|
{ |
|
struct loc_track *t = seq->private; |
|
|
|
v = ppos; |
|
++*ppos; |
|
if (*ppos <= t->count) |
|
return v; |
|
|
|
return NULL; |
|
} |
|
|
|
static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos) |
|
{ |
|
return ppos; |
|
} |
|
|
|
static const struct seq_operations slab_debugfs_sops = { |
|
.start = slab_debugfs_start, |
|
.next = slab_debugfs_next, |
|
.stop = slab_debugfs_stop, |
|
.show = slab_debugfs_show, |
|
}; |
|
|
|
static int slab_debug_trace_open(struct inode *inode, struct file *filep) |
|
{ |
|
|
|
struct kmem_cache_node *n; |
|
enum track_item alloc; |
|
int node; |
|
struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops, |
|
sizeof(struct loc_track)); |
|
struct kmem_cache *s = file_inode(filep)->i_private; |
|
|
|
if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0) |
|
alloc = TRACK_ALLOC; |
|
else |
|
alloc = TRACK_FREE; |
|
|
|
if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) |
|
return -ENOMEM; |
|
|
|
/* Push back cpu slabs */ |
|
flush_all(s); |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
unsigned long flags; |
|
struct page *page; |
|
|
|
if (!atomic_long_read(&n->nr_slabs)) |
|
continue; |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
list_for_each_entry(page, &n->partial, slab_list) |
|
process_slab(t, s, page, alloc); |
|
list_for_each_entry(page, &n->full, slab_list) |
|
process_slab(t, s, page, alloc); |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int slab_debug_trace_release(struct inode *inode, struct file *file) |
|
{ |
|
struct seq_file *seq = file->private_data; |
|
struct loc_track *t = seq->private; |
|
|
|
free_loc_track(t); |
|
return seq_release_private(inode, file); |
|
} |
|
|
|
static const struct file_operations slab_debugfs_fops = { |
|
.open = slab_debug_trace_open, |
|
.read = seq_read, |
|
.llseek = seq_lseek, |
|
.release = slab_debug_trace_release, |
|
}; |
|
|
|
static void debugfs_slab_add(struct kmem_cache *s) |
|
{ |
|
struct dentry *slab_cache_dir; |
|
|
|
if (unlikely(!slab_debugfs_root)) |
|
return; |
|
|
|
slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root); |
|
|
|
debugfs_create_file("alloc_traces", 0400, |
|
slab_cache_dir, s, &slab_debugfs_fops); |
|
|
|
debugfs_create_file("free_traces", 0400, |
|
slab_cache_dir, s, &slab_debugfs_fops); |
|
} |
|
|
|
void debugfs_slab_release(struct kmem_cache *s) |
|
{ |
|
debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root)); |
|
} |
|
|
|
static int __init slab_debugfs_init(void) |
|
{ |
|
struct kmem_cache *s; |
|
|
|
slab_debugfs_root = debugfs_create_dir("slab", NULL); |
|
|
|
list_for_each_entry(s, &slab_caches, list) |
|
if (s->flags & SLAB_STORE_USER) |
|
debugfs_slab_add(s); |
|
|
|
return 0; |
|
|
|
} |
|
__initcall(slab_debugfs_init); |
|
#endif |
|
/* |
|
* The /proc/slabinfo ABI |
|
*/ |
|
#ifdef CONFIG_SLUB_DEBUG |
|
void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo) |
|
{ |
|
unsigned long nr_slabs = 0; |
|
unsigned long nr_objs = 0; |
|
unsigned long nr_free = 0; |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) { |
|
nr_slabs += node_nr_slabs(n); |
|
nr_objs += node_nr_objs(n); |
|
nr_free += count_partial(n, count_free); |
|
} |
|
|
|
sinfo->active_objs = nr_objs - nr_free; |
|
sinfo->num_objs = nr_objs; |
|
sinfo->active_slabs = nr_slabs; |
|
sinfo->num_slabs = nr_slabs; |
|
sinfo->objects_per_slab = oo_objects(s->oo); |
|
sinfo->cache_order = oo_order(s->oo); |
|
} |
|
|
|
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s) |
|
{ |
|
} |
|
|
|
ssize_t slabinfo_write(struct file *file, const char __user *buffer, |
|
size_t count, loff_t *ppos) |
|
{ |
|
return -EIO; |
|
} |
|
#endif /* CONFIG_SLUB_DEBUG */
|
|
|