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4053 lines
102 KiB
4053 lines
102 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/mm/slab.c |
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* Written by Mark Hemment, 1996/97. |
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* ([email protected]) |
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* |
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* kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli |
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* |
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* Major cleanup, different bufctl logic, per-cpu arrays |
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* (c) 2000 Manfred Spraul |
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* |
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* Cleanup, make the head arrays unconditional, preparation for NUMA |
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* (c) 2002 Manfred Spraul |
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* |
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* An implementation of the Slab Allocator as described in outline in; |
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* UNIX Internals: The New Frontiers by Uresh Vahalia |
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* Pub: Prentice Hall ISBN 0-13-101908-2 |
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* or with a little more detail in; |
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* The Slab Allocator: An Object-Caching Kernel Memory Allocator |
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* Jeff Bonwick (Sun Microsystems). |
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* Presented at: USENIX Summer 1994 Technical Conference |
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* |
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* The memory is organized in caches, one cache for each object type. |
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* (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) |
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* Each cache consists out of many slabs (they are small (usually one |
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* page long) and always contiguous), and each slab contains multiple |
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* initialized objects. |
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* |
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* This means, that your constructor is used only for newly allocated |
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* slabs and you must pass objects with the same initializations to |
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* kmem_cache_free. |
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* |
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* Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, |
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* normal). If you need a special memory type, then must create a new |
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* cache for that memory type. |
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* |
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* In order to reduce fragmentation, the slabs are sorted in 3 groups: |
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* full slabs with 0 free objects |
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* partial slabs |
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* empty slabs with no allocated objects |
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* |
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* If partial slabs exist, then new allocations come from these slabs, |
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* otherwise from empty slabs or new slabs are allocated. |
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* |
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* kmem_cache_destroy() CAN CRASH if you try to allocate from the cache |
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* during kmem_cache_destroy(). The caller must prevent concurrent allocs. |
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* |
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* Each cache has a short per-cpu head array, most allocs |
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* and frees go into that array, and if that array overflows, then 1/2 |
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* of the entries in the array are given back into the global cache. |
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* The head array is strictly LIFO and should improve the cache hit rates. |
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* On SMP, it additionally reduces the spinlock operations. |
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* |
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* The c_cpuarray may not be read with enabled local interrupts - |
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* it's changed with a smp_call_function(). |
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* |
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* SMP synchronization: |
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* constructors and destructors are called without any locking. |
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* Several members in struct kmem_cache and struct slab never change, they |
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* are accessed without any locking. |
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* The per-cpu arrays are never accessed from the wrong cpu, no locking, |
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* and local interrupts are disabled so slab code is preempt-safe. |
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* The non-constant members are protected with a per-cache irq spinlock. |
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* |
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* Many thanks to Mark Hemment, who wrote another per-cpu slab patch |
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* in 2000 - many ideas in the current implementation are derived from |
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* his patch. |
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* |
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* Further notes from the original documentation: |
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* |
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* 11 April '97. Started multi-threading - markhe |
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* The global cache-chain is protected by the mutex 'slab_mutex'. |
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* The sem is only needed when accessing/extending the cache-chain, which |
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* can never happen inside an interrupt (kmem_cache_create(), |
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* kmem_cache_shrink() and kmem_cache_reap()). |
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* |
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* At present, each engine can be growing a cache. This should be blocked. |
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* |
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* 15 March 2005. NUMA slab allocator. |
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* Shai Fultheim <[email protected]>. |
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* Shobhit Dayal <[email protected]> |
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* Alok N Kataria <[email protected]> |
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* Christoph Lameter <[email protected]> |
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* |
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* Modified the slab allocator to be node aware on NUMA systems. |
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* Each node has its own list of partial, free and full slabs. |
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* All object allocations for a node occur from node specific slab lists. |
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*/ |
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|
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#include <linux/slab.h> |
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#include <linux/mm.h> |
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#include <linux/poison.h> |
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#include <linux/swap.h> |
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#include <linux/cache.h> |
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#include <linux/interrupt.h> |
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#include <linux/init.h> |
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#include <linux/compiler.h> |
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#include <linux/cpuset.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/notifier.h> |
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#include <linux/kallsyms.h> |
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#include <linux/kfence.h> |
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#include <linux/cpu.h> |
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#include <linux/sysctl.h> |
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#include <linux/module.h> |
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#include <linux/rcupdate.h> |
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#include <linux/string.h> |
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#include <linux/uaccess.h> |
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#include <linux/nodemask.h> |
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#include <linux/kmemleak.h> |
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#include <linux/mempolicy.h> |
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#include <linux/mutex.h> |
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#include <linux/fault-inject.h> |
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#include <linux/rtmutex.h> |
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#include <linux/reciprocal_div.h> |
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#include <linux/debugobjects.h> |
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#include <linux/memory.h> |
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#include <linux/prefetch.h> |
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#include <linux/sched/task_stack.h> |
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|
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#include <net/sock.h> |
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|
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#include <asm/cacheflush.h> |
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#include <asm/tlbflush.h> |
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#include <asm/page.h> |
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|
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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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#include "slab.h" |
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|
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/* |
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* DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON. |
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* 0 for faster, smaller code (especially in the critical paths). |
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* |
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* STATS - 1 to collect stats for /proc/slabinfo. |
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* 0 for faster, smaller code (especially in the critical paths). |
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* |
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* FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) |
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*/ |
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|
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#ifdef CONFIG_DEBUG_SLAB |
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#define DEBUG 1 |
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#define STATS 1 |
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#define FORCED_DEBUG 1 |
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#else |
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#define DEBUG 0 |
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#define STATS 0 |
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#define FORCED_DEBUG 0 |
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#endif |
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|
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/* Shouldn't this be in a header file somewhere? */ |
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#define BYTES_PER_WORD sizeof(void *) |
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#define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long)) |
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|
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#ifndef ARCH_KMALLOC_FLAGS |
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#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN |
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#endif |
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|
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#define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \ |
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<= SLAB_OBJ_MIN_SIZE) ? 1 : 0) |
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|
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#if FREELIST_BYTE_INDEX |
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typedef unsigned char freelist_idx_t; |
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#else |
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typedef unsigned short freelist_idx_t; |
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#endif |
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|
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#define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1) |
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|
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/* |
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* struct array_cache |
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* |
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* Purpose: |
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* - LIFO ordering, to hand out cache-warm objects from _alloc |
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* - reduce the number of linked list operations |
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* - reduce spinlock operations |
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* |
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* The limit is stored in the per-cpu structure to reduce the data cache |
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* footprint. |
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* |
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*/ |
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struct array_cache { |
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unsigned int avail; |
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unsigned int limit; |
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unsigned int batchcount; |
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unsigned int touched; |
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void *entry[]; /* |
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* Must have this definition in here for the proper |
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* alignment of array_cache. Also simplifies accessing |
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* the entries. |
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*/ |
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}; |
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|
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struct alien_cache { |
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spinlock_t lock; |
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struct array_cache ac; |
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}; |
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|
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/* |
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* Need this for bootstrapping a per node allocator. |
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*/ |
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#define NUM_INIT_LISTS (2 * MAX_NUMNODES) |
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static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS]; |
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#define CACHE_CACHE 0 |
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#define SIZE_NODE (MAX_NUMNODES) |
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|
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static int drain_freelist(struct kmem_cache *cache, |
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struct kmem_cache_node *n, int tofree); |
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static void free_block(struct kmem_cache *cachep, void **objpp, int len, |
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int node, struct list_head *list); |
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static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list); |
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static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); |
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static void cache_reap(struct work_struct *unused); |
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|
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static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, |
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void **list); |
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static inline void fixup_slab_list(struct kmem_cache *cachep, |
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struct kmem_cache_node *n, struct slab *slab, |
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void **list); |
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static int slab_early_init = 1; |
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|
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#define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) |
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|
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static void kmem_cache_node_init(struct kmem_cache_node *parent) |
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{ |
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INIT_LIST_HEAD(&parent->slabs_full); |
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INIT_LIST_HEAD(&parent->slabs_partial); |
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INIT_LIST_HEAD(&parent->slabs_free); |
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parent->total_slabs = 0; |
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parent->free_slabs = 0; |
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parent->shared = NULL; |
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parent->alien = NULL; |
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parent->colour_next = 0; |
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spin_lock_init(&parent->list_lock); |
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parent->free_objects = 0; |
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parent->free_touched = 0; |
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} |
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|
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#define MAKE_LIST(cachep, listp, slab, nodeid) \ |
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do { \ |
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INIT_LIST_HEAD(listp); \ |
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list_splice(&get_node(cachep, nodeid)->slab, listp); \ |
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} while (0) |
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|
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#define MAKE_ALL_LISTS(cachep, ptr, nodeid) \ |
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do { \ |
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MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \ |
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MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \ |
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MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ |
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} while (0) |
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|
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#define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U) |
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#define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U) |
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#define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB) |
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#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) |
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|
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#define BATCHREFILL_LIMIT 16 |
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/* |
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* Optimization question: fewer reaps means less probability for unnecessary |
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* cpucache drain/refill cycles. |
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* |
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* OTOH the cpuarrays can contain lots of objects, |
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* which could lock up otherwise freeable slabs. |
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*/ |
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#define REAPTIMEOUT_AC (2*HZ) |
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#define REAPTIMEOUT_NODE (4*HZ) |
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|
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#if STATS |
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#define STATS_INC_ACTIVE(x) ((x)->num_active++) |
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#define STATS_DEC_ACTIVE(x) ((x)->num_active--) |
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#define STATS_INC_ALLOCED(x) ((x)->num_allocations++) |
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#define STATS_INC_GROWN(x) ((x)->grown++) |
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#define STATS_ADD_REAPED(x, y) ((x)->reaped += (y)) |
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#define STATS_SET_HIGH(x) \ |
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do { \ |
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if ((x)->num_active > (x)->high_mark) \ |
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(x)->high_mark = (x)->num_active; \ |
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} while (0) |
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#define STATS_INC_ERR(x) ((x)->errors++) |
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#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) |
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#define STATS_INC_NODEFREES(x) ((x)->node_frees++) |
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#define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++) |
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#define STATS_SET_FREEABLE(x, i) \ |
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do { \ |
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if ((x)->max_freeable < i) \ |
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(x)->max_freeable = i; \ |
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} while (0) |
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#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) |
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#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) |
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#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) |
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#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) |
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#else |
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#define STATS_INC_ACTIVE(x) do { } while (0) |
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#define STATS_DEC_ACTIVE(x) do { } while (0) |
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#define STATS_INC_ALLOCED(x) do { } while (0) |
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#define STATS_INC_GROWN(x) do { } while (0) |
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#define STATS_ADD_REAPED(x, y) do { (void)(y); } while (0) |
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#define STATS_SET_HIGH(x) do { } while (0) |
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#define STATS_INC_ERR(x) do { } while (0) |
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#define STATS_INC_NODEALLOCS(x) do { } while (0) |
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#define STATS_INC_NODEFREES(x) do { } while (0) |
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#define STATS_INC_ACOVERFLOW(x) do { } while (0) |
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#define STATS_SET_FREEABLE(x, i) do { } while (0) |
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#define STATS_INC_ALLOCHIT(x) do { } while (0) |
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#define STATS_INC_ALLOCMISS(x) do { } while (0) |
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#define STATS_INC_FREEHIT(x) do { } while (0) |
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#define STATS_INC_FREEMISS(x) do { } while (0) |
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#endif |
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|
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#if DEBUG |
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|
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/* |
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* memory layout of objects: |
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* 0 : objp |
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* 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that |
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* the end of an object is aligned with the end of the real |
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* allocation. Catches writes behind the end of the allocation. |
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* cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1: |
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* redzone word. |
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* cachep->obj_offset: The real object. |
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* cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] |
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* cachep->size - 1* BYTES_PER_WORD: last caller address |
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* [BYTES_PER_WORD long] |
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*/ |
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static int obj_offset(struct kmem_cache *cachep) |
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{ |
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return cachep->obj_offset; |
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} |
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|
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static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp) |
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{ |
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BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); |
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return (unsigned long long *) (objp + obj_offset(cachep) - |
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sizeof(unsigned long long)); |
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} |
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|
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static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp) |
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{ |
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BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); |
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if (cachep->flags & SLAB_STORE_USER) |
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return (unsigned long long *)(objp + cachep->size - |
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sizeof(unsigned long long) - |
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REDZONE_ALIGN); |
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return (unsigned long long *) (objp + cachep->size - |
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sizeof(unsigned long long)); |
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} |
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|
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static void **dbg_userword(struct kmem_cache *cachep, void *objp) |
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{ |
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BUG_ON(!(cachep->flags & SLAB_STORE_USER)); |
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return (void **)(objp + cachep->size - BYTES_PER_WORD); |
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} |
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|
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#else |
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|
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#define obj_offset(x) 0 |
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#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) |
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#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) |
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#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) |
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|
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#endif |
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|
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/* |
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* Do not go above this order unless 0 objects fit into the slab or |
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* overridden on the command line. |
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*/ |
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#define SLAB_MAX_ORDER_HI 1 |
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#define SLAB_MAX_ORDER_LO 0 |
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static int slab_max_order = SLAB_MAX_ORDER_LO; |
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static bool slab_max_order_set __initdata; |
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|
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static inline void *index_to_obj(struct kmem_cache *cache, |
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const struct slab *slab, unsigned int idx) |
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{ |
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return slab->s_mem + cache->size * idx; |
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} |
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|
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#define BOOT_CPUCACHE_ENTRIES 1 |
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/* internal cache of cache description objs */ |
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static struct kmem_cache kmem_cache_boot = { |
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.batchcount = 1, |
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.limit = BOOT_CPUCACHE_ENTRIES, |
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.shared = 1, |
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.size = sizeof(struct kmem_cache), |
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.name = "kmem_cache", |
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}; |
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|
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static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); |
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|
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static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) |
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{ |
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return this_cpu_ptr(cachep->cpu_cache); |
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} |
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|
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/* |
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* Calculate the number of objects and left-over bytes for a given buffer size. |
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*/ |
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static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size, |
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slab_flags_t flags, size_t *left_over) |
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{ |
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unsigned int num; |
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size_t slab_size = PAGE_SIZE << gfporder; |
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|
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/* |
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* The slab management structure can be either off the slab or |
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* on it. For the latter case, the memory allocated for a |
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* slab is used for: |
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* |
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* - @buffer_size bytes for each object |
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* - One freelist_idx_t for each object |
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* |
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* We don't need to consider alignment of freelist because |
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* freelist will be at the end of slab page. The objects will be |
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* at the correct alignment. |
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* |
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* If the slab management structure is off the slab, then the |
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* alignment will already be calculated into the size. Because |
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* the slabs are all pages aligned, the objects will be at the |
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* correct alignment when allocated. |
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*/ |
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if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) { |
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num = slab_size / buffer_size; |
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*left_over = slab_size % buffer_size; |
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} else { |
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num = slab_size / (buffer_size + sizeof(freelist_idx_t)); |
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*left_over = slab_size % |
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(buffer_size + sizeof(freelist_idx_t)); |
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} |
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|
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return num; |
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} |
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|
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#if DEBUG |
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#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) |
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|
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static void __slab_error(const char *function, struct kmem_cache *cachep, |
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char *msg) |
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{ |
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pr_err("slab error in %s(): cache `%s': %s\n", |
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function, cachep->name, msg); |
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dump_stack(); |
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add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
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} |
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#endif |
|
|
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/* |
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* By default on NUMA we use alien caches to stage the freeing of |
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* objects allocated from other nodes. This causes massive memory |
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* inefficiencies when using fake NUMA setup to split memory into a |
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* large number of small nodes, so it can be disabled on the command |
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* line |
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*/ |
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|
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static int use_alien_caches __read_mostly = 1; |
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static int __init noaliencache_setup(char *s) |
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{ |
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use_alien_caches = 0; |
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return 1; |
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} |
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__setup("noaliencache", noaliencache_setup); |
|
|
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static int __init slab_max_order_setup(char *str) |
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{ |
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get_option(&str, &slab_max_order); |
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slab_max_order = slab_max_order < 0 ? 0 : |
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min(slab_max_order, MAX_ORDER - 1); |
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slab_max_order_set = true; |
|
|
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return 1; |
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} |
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__setup("slab_max_order=", slab_max_order_setup); |
|
|
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#ifdef CONFIG_NUMA |
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/* |
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* Special reaping functions for NUMA systems called from cache_reap(). |
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* These take care of doing round robin flushing of alien caches (containing |
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* objects freed on different nodes from which they were allocated) and the |
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* flushing of remote pcps by calling drain_node_pages. |
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*/ |
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static DEFINE_PER_CPU(unsigned long, slab_reap_node); |
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|
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static void init_reap_node(int cpu) |
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{ |
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per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu), |
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node_online_map); |
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} |
|
|
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static void next_reap_node(void) |
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{ |
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int node = __this_cpu_read(slab_reap_node); |
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|
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node = next_node_in(node, node_online_map); |
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__this_cpu_write(slab_reap_node, node); |
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} |
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|
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#else |
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#define init_reap_node(cpu) do { } while (0) |
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#define next_reap_node(void) do { } while (0) |
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#endif |
|
|
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/* |
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* Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz |
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* via the workqueue/eventd. |
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* Add the CPU number into the expiration time to minimize the possibility of |
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* the CPUs getting into lockstep and contending for the global cache chain |
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* lock. |
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*/ |
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static void start_cpu_timer(int cpu) |
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{ |
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struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); |
|
|
|
if (reap_work->work.func == NULL) { |
|
init_reap_node(cpu); |
|
INIT_DEFERRABLE_WORK(reap_work, cache_reap); |
|
schedule_delayed_work_on(cpu, reap_work, |
|
__round_jiffies_relative(HZ, cpu)); |
|
} |
|
} |
|
|
|
static void init_arraycache(struct array_cache *ac, int limit, int batch) |
|
{ |
|
if (ac) { |
|
ac->avail = 0; |
|
ac->limit = limit; |
|
ac->batchcount = batch; |
|
ac->touched = 0; |
|
} |
|
} |
|
|
|
static struct array_cache *alloc_arraycache(int node, int entries, |
|
int batchcount, gfp_t gfp) |
|
{ |
|
size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache); |
|
struct array_cache *ac = NULL; |
|
|
|
ac = kmalloc_node(memsize, gfp, node); |
|
/* |
|
* The array_cache structures contain pointers to free object. |
|
* However, when such objects are allocated or transferred to another |
|
* cache the pointers are not cleared and they could be counted as |
|
* valid references during a kmemleak scan. Therefore, kmemleak must |
|
* not scan such objects. |
|
*/ |
|
kmemleak_no_scan(ac); |
|
init_arraycache(ac, entries, batchcount); |
|
return ac; |
|
} |
|
|
|
static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep, |
|
struct slab *slab, void *objp) |
|
{ |
|
struct kmem_cache_node *n; |
|
int slab_node; |
|
LIST_HEAD(list); |
|
|
|
slab_node = slab_nid(slab); |
|
n = get_node(cachep, slab_node); |
|
|
|
spin_lock(&n->list_lock); |
|
free_block(cachep, &objp, 1, slab_node, &list); |
|
spin_unlock(&n->list_lock); |
|
|
|
slabs_destroy(cachep, &list); |
|
} |
|
|
|
/* |
|
* Transfer objects in one arraycache to another. |
|
* Locking must be handled by the caller. |
|
* |
|
* Return the number of entries transferred. |
|
*/ |
|
static int transfer_objects(struct array_cache *to, |
|
struct array_cache *from, unsigned int max) |
|
{ |
|
/* Figure out how many entries to transfer */ |
|
int nr = min3(from->avail, max, to->limit - to->avail); |
|
|
|
if (!nr) |
|
return 0; |
|
|
|
memcpy(to->entry + to->avail, from->entry + from->avail - nr, |
|
sizeof(void *) *nr); |
|
|
|
from->avail -= nr; |
|
to->avail += nr; |
|
return nr; |
|
} |
|
|
|
/* &alien->lock must be held by alien callers. */ |
|
static __always_inline void __free_one(struct array_cache *ac, void *objp) |
|
{ |
|
/* Avoid trivial double-free. */ |
|
if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && |
|
WARN_ON_ONCE(ac->avail > 0 && ac->entry[ac->avail - 1] == objp)) |
|
return; |
|
ac->entry[ac->avail++] = objp; |
|
} |
|
|
|
#ifndef CONFIG_NUMA |
|
|
|
#define drain_alien_cache(cachep, alien) do { } while (0) |
|
#define reap_alien(cachep, n) do { } while (0) |
|
|
|
static inline struct alien_cache **alloc_alien_cache(int node, |
|
int limit, gfp_t gfp) |
|
{ |
|
return NULL; |
|
} |
|
|
|
static inline void free_alien_cache(struct alien_cache **ac_ptr) |
|
{ |
|
} |
|
|
|
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) |
|
{ |
|
return 0; |
|
} |
|
|
|
static inline gfp_t gfp_exact_node(gfp_t flags) |
|
{ |
|
return flags & ~__GFP_NOFAIL; |
|
} |
|
|
|
#else /* CONFIG_NUMA */ |
|
|
|
static struct alien_cache *__alloc_alien_cache(int node, int entries, |
|
int batch, gfp_t gfp) |
|
{ |
|
size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache); |
|
struct alien_cache *alc = NULL; |
|
|
|
alc = kmalloc_node(memsize, gfp, node); |
|
if (alc) { |
|
kmemleak_no_scan(alc); |
|
init_arraycache(&alc->ac, entries, batch); |
|
spin_lock_init(&alc->lock); |
|
} |
|
return alc; |
|
} |
|
|
|
static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) |
|
{ |
|
struct alien_cache **alc_ptr; |
|
int i; |
|
|
|
if (limit > 1) |
|
limit = 12; |
|
alc_ptr = kcalloc_node(nr_node_ids, sizeof(void *), gfp, node); |
|
if (!alc_ptr) |
|
return NULL; |
|
|
|
for_each_node(i) { |
|
if (i == node || !node_online(i)) |
|
continue; |
|
alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp); |
|
if (!alc_ptr[i]) { |
|
for (i--; i >= 0; i--) |
|
kfree(alc_ptr[i]); |
|
kfree(alc_ptr); |
|
return NULL; |
|
} |
|
} |
|
return alc_ptr; |
|
} |
|
|
|
static void free_alien_cache(struct alien_cache **alc_ptr) |
|
{ |
|
int i; |
|
|
|
if (!alc_ptr) |
|
return; |
|
for_each_node(i) |
|
kfree(alc_ptr[i]); |
|
kfree(alc_ptr); |
|
} |
|
|
|
static void __drain_alien_cache(struct kmem_cache *cachep, |
|
struct array_cache *ac, int node, |
|
struct list_head *list) |
|
{ |
|
struct kmem_cache_node *n = get_node(cachep, node); |
|
|
|
if (ac->avail) { |
|
spin_lock(&n->list_lock); |
|
/* |
|
* Stuff objects into the remote nodes shared array first. |
|
* That way we could avoid the overhead of putting the objects |
|
* into the free lists and getting them back later. |
|
*/ |
|
if (n->shared) |
|
transfer_objects(n->shared, ac, ac->limit); |
|
|
|
free_block(cachep, ac->entry, ac->avail, node, list); |
|
ac->avail = 0; |
|
spin_unlock(&n->list_lock); |
|
} |
|
} |
|
|
|
/* |
|
* Called from cache_reap() to regularly drain alien caches round robin. |
|
*/ |
|
static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n) |
|
{ |
|
int node = __this_cpu_read(slab_reap_node); |
|
|
|
if (n->alien) { |
|
struct alien_cache *alc = n->alien[node]; |
|
struct array_cache *ac; |
|
|
|
if (alc) { |
|
ac = &alc->ac; |
|
if (ac->avail && spin_trylock_irq(&alc->lock)) { |
|
LIST_HEAD(list); |
|
|
|
__drain_alien_cache(cachep, ac, node, &list); |
|
spin_unlock_irq(&alc->lock); |
|
slabs_destroy(cachep, &list); |
|
} |
|
} |
|
} |
|
} |
|
|
|
static void drain_alien_cache(struct kmem_cache *cachep, |
|
struct alien_cache **alien) |
|
{ |
|
int i = 0; |
|
struct alien_cache *alc; |
|
struct array_cache *ac; |
|
unsigned long flags; |
|
|
|
for_each_online_node(i) { |
|
alc = alien[i]; |
|
if (alc) { |
|
LIST_HEAD(list); |
|
|
|
ac = &alc->ac; |
|
spin_lock_irqsave(&alc->lock, flags); |
|
__drain_alien_cache(cachep, ac, i, &list); |
|
spin_unlock_irqrestore(&alc->lock, flags); |
|
slabs_destroy(cachep, &list); |
|
} |
|
} |
|
} |
|
|
|
static int __cache_free_alien(struct kmem_cache *cachep, void *objp, |
|
int node, int slab_node) |
|
{ |
|
struct kmem_cache_node *n; |
|
struct alien_cache *alien = NULL; |
|
struct array_cache *ac; |
|
LIST_HEAD(list); |
|
|
|
n = get_node(cachep, node); |
|
STATS_INC_NODEFREES(cachep); |
|
if (n->alien && n->alien[slab_node]) { |
|
alien = n->alien[slab_node]; |
|
ac = &alien->ac; |
|
spin_lock(&alien->lock); |
|
if (unlikely(ac->avail == ac->limit)) { |
|
STATS_INC_ACOVERFLOW(cachep); |
|
__drain_alien_cache(cachep, ac, slab_node, &list); |
|
} |
|
__free_one(ac, objp); |
|
spin_unlock(&alien->lock); |
|
slabs_destroy(cachep, &list); |
|
} else { |
|
n = get_node(cachep, slab_node); |
|
spin_lock(&n->list_lock); |
|
free_block(cachep, &objp, 1, slab_node, &list); |
|
spin_unlock(&n->list_lock); |
|
slabs_destroy(cachep, &list); |
|
} |
|
return 1; |
|
} |
|
|
|
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) |
|
{ |
|
int slab_node = slab_nid(virt_to_slab(objp)); |
|
int node = numa_mem_id(); |
|
/* |
|
* Make sure we are not freeing an object from another node to the array |
|
* cache on this cpu. |
|
*/ |
|
if (likely(node == slab_node)) |
|
return 0; |
|
|
|
return __cache_free_alien(cachep, objp, node, slab_node); |
|
} |
|
|
|
/* |
|
* Construct gfp mask to allocate from a specific node but do not reclaim or |
|
* warn about failures. |
|
*/ |
|
static inline gfp_t gfp_exact_node(gfp_t flags) |
|
{ |
|
return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL); |
|
} |
|
#endif |
|
|
|
static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp) |
|
{ |
|
struct kmem_cache_node *n; |
|
|
|
/* |
|
* Set up the kmem_cache_node for cpu before we can |
|
* begin anything. Make sure some other cpu on this |
|
* node has not already allocated this |
|
*/ |
|
n = get_node(cachep, node); |
|
if (n) { |
|
spin_lock_irq(&n->list_lock); |
|
n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + |
|
cachep->num; |
|
spin_unlock_irq(&n->list_lock); |
|
|
|
return 0; |
|
} |
|
|
|
n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node); |
|
if (!n) |
|
return -ENOMEM; |
|
|
|
kmem_cache_node_init(n); |
|
n->next_reap = jiffies + REAPTIMEOUT_NODE + |
|
((unsigned long)cachep) % REAPTIMEOUT_NODE; |
|
|
|
n->free_limit = |
|
(1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; |
|
|
|
/* |
|
* The kmem_cache_nodes don't come and go as CPUs |
|
* come and go. slab_mutex provides sufficient |
|
* protection here. |
|
*/ |
|
cachep->node[node] = n; |
|
|
|
return 0; |
|
} |
|
|
|
#if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP) |
|
/* |
|
* Allocates and initializes node for a node on each slab cache, used for |
|
* either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node |
|
* will be allocated off-node since memory is not yet online for the new node. |
|
* When hotplugging memory or a cpu, existing nodes are not replaced if |
|
* already in use. |
|
* |
|
* Must hold slab_mutex. |
|
*/ |
|
static int init_cache_node_node(int node) |
|
{ |
|
int ret; |
|
struct kmem_cache *cachep; |
|
|
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
ret = init_cache_node(cachep, node, GFP_KERNEL); |
|
if (ret) |
|
return ret; |
|
} |
|
|
|
return 0; |
|
} |
|
#endif |
|
|
|
static int setup_kmem_cache_node(struct kmem_cache *cachep, |
|
int node, gfp_t gfp, bool force_change) |
|
{ |
|
int ret = -ENOMEM; |
|
struct kmem_cache_node *n; |
|
struct array_cache *old_shared = NULL; |
|
struct array_cache *new_shared = NULL; |
|
struct alien_cache **new_alien = NULL; |
|
LIST_HEAD(list); |
|
|
|
if (use_alien_caches) { |
|
new_alien = alloc_alien_cache(node, cachep->limit, gfp); |
|
if (!new_alien) |
|
goto fail; |
|
} |
|
|
|
if (cachep->shared) { |
|
new_shared = alloc_arraycache(node, |
|
cachep->shared * cachep->batchcount, 0xbaadf00d, gfp); |
|
if (!new_shared) |
|
goto fail; |
|
} |
|
|
|
ret = init_cache_node(cachep, node, gfp); |
|
if (ret) |
|
goto fail; |
|
|
|
n = get_node(cachep, node); |
|
spin_lock_irq(&n->list_lock); |
|
if (n->shared && force_change) { |
|
free_block(cachep, n->shared->entry, |
|
n->shared->avail, node, &list); |
|
n->shared->avail = 0; |
|
} |
|
|
|
if (!n->shared || force_change) { |
|
old_shared = n->shared; |
|
n->shared = new_shared; |
|
new_shared = NULL; |
|
} |
|
|
|
if (!n->alien) { |
|
n->alien = new_alien; |
|
new_alien = NULL; |
|
} |
|
|
|
spin_unlock_irq(&n->list_lock); |
|
slabs_destroy(cachep, &list); |
|
|
|
/* |
|
* To protect lockless access to n->shared during irq disabled context. |
|
* If n->shared isn't NULL in irq disabled context, accessing to it is |
|
* guaranteed to be valid until irq is re-enabled, because it will be |
|
* freed after synchronize_rcu(). |
|
*/ |
|
if (old_shared && force_change) |
|
synchronize_rcu(); |
|
|
|
fail: |
|
kfree(old_shared); |
|
kfree(new_shared); |
|
free_alien_cache(new_alien); |
|
|
|
return ret; |
|
} |
|
|
|
#ifdef CONFIG_SMP |
|
|
|
static void cpuup_canceled(long cpu) |
|
{ |
|
struct kmem_cache *cachep; |
|
struct kmem_cache_node *n = NULL; |
|
int node = cpu_to_mem(cpu); |
|
const struct cpumask *mask = cpumask_of_node(node); |
|
|
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
struct array_cache *nc; |
|
struct array_cache *shared; |
|
struct alien_cache **alien; |
|
LIST_HEAD(list); |
|
|
|
n = get_node(cachep, node); |
|
if (!n) |
|
continue; |
|
|
|
spin_lock_irq(&n->list_lock); |
|
|
|
/* Free limit for this kmem_cache_node */ |
|
n->free_limit -= cachep->batchcount; |
|
|
|
/* cpu is dead; no one can alloc from it. */ |
|
nc = per_cpu_ptr(cachep->cpu_cache, cpu); |
|
free_block(cachep, nc->entry, nc->avail, node, &list); |
|
nc->avail = 0; |
|
|
|
if (!cpumask_empty(mask)) { |
|
spin_unlock_irq(&n->list_lock); |
|
goto free_slab; |
|
} |
|
|
|
shared = n->shared; |
|
if (shared) { |
|
free_block(cachep, shared->entry, |
|
shared->avail, node, &list); |
|
n->shared = NULL; |
|
} |
|
|
|
alien = n->alien; |
|
n->alien = NULL; |
|
|
|
spin_unlock_irq(&n->list_lock); |
|
|
|
kfree(shared); |
|
if (alien) { |
|
drain_alien_cache(cachep, alien); |
|
free_alien_cache(alien); |
|
} |
|
|
|
free_slab: |
|
slabs_destroy(cachep, &list); |
|
} |
|
/* |
|
* In the previous loop, all the objects were freed to |
|
* the respective cache's slabs, now we can go ahead and |
|
* shrink each nodelist to its limit. |
|
*/ |
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
n = get_node(cachep, node); |
|
if (!n) |
|
continue; |
|
drain_freelist(cachep, n, INT_MAX); |
|
} |
|
} |
|
|
|
static int cpuup_prepare(long cpu) |
|
{ |
|
struct kmem_cache *cachep; |
|
int node = cpu_to_mem(cpu); |
|
int err; |
|
|
|
/* |
|
* We need to do this right in the beginning since |
|
* alloc_arraycache's are going to use this list. |
|
* kmalloc_node allows us to add the slab to the right |
|
* kmem_cache_node and not this cpu's kmem_cache_node |
|
*/ |
|
err = init_cache_node_node(node); |
|
if (err < 0) |
|
goto bad; |
|
|
|
/* |
|
* Now we can go ahead with allocating the shared arrays and |
|
* array caches |
|
*/ |
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false); |
|
if (err) |
|
goto bad; |
|
} |
|
|
|
return 0; |
|
bad: |
|
cpuup_canceled(cpu); |
|
return -ENOMEM; |
|
} |
|
|
|
int slab_prepare_cpu(unsigned int cpu) |
|
{ |
|
int err; |
|
|
|
mutex_lock(&slab_mutex); |
|
err = cpuup_prepare(cpu); |
|
mutex_unlock(&slab_mutex); |
|
return err; |
|
} |
|
|
|
/* |
|
* This is called for a failed online attempt and for a successful |
|
* offline. |
|
* |
|
* Even if all the cpus of a node are down, we don't free the |
|
* kmem_cache_node of any cache. This is to avoid a race between cpu_down, and |
|
* a kmalloc allocation from another cpu for memory from the node of |
|
* the cpu going down. The kmem_cache_node structure is usually allocated from |
|
* kmem_cache_create() and gets destroyed at kmem_cache_destroy(). |
|
*/ |
|
int slab_dead_cpu(unsigned int cpu) |
|
{ |
|
mutex_lock(&slab_mutex); |
|
cpuup_canceled(cpu); |
|
mutex_unlock(&slab_mutex); |
|
return 0; |
|
} |
|
#endif |
|
|
|
static int slab_online_cpu(unsigned int cpu) |
|
{ |
|
start_cpu_timer(cpu); |
|
return 0; |
|
} |
|
|
|
static int slab_offline_cpu(unsigned int cpu) |
|
{ |
|
/* |
|
* Shutdown cache reaper. Note that the slab_mutex is held so |
|
* that if cache_reap() is invoked it cannot do anything |
|
* expensive but will only modify reap_work and reschedule the |
|
* timer. |
|
*/ |
|
cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu)); |
|
/* Now the cache_reaper is guaranteed to be not running. */ |
|
per_cpu(slab_reap_work, cpu).work.func = NULL; |
|
return 0; |
|
} |
|
|
|
#if defined(CONFIG_NUMA) |
|
/* |
|
* Drains freelist for a node on each slab cache, used for memory hot-remove. |
|
* Returns -EBUSY if all objects cannot be drained so that the node is not |
|
* removed. |
|
* |
|
* Must hold slab_mutex. |
|
*/ |
|
static int __meminit drain_cache_node_node(int node) |
|
{ |
|
struct kmem_cache *cachep; |
|
int ret = 0; |
|
|
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
struct kmem_cache_node *n; |
|
|
|
n = get_node(cachep, node); |
|
if (!n) |
|
continue; |
|
|
|
drain_freelist(cachep, n, INT_MAX); |
|
|
|
if (!list_empty(&n->slabs_full) || |
|
!list_empty(&n->slabs_partial)) { |
|
ret = -EBUSY; |
|
break; |
|
} |
|
} |
|
return ret; |
|
} |
|
|
|
static int __meminit slab_memory_callback(struct notifier_block *self, |
|
unsigned long action, void *arg) |
|
{ |
|
struct memory_notify *mnb = arg; |
|
int ret = 0; |
|
int nid; |
|
|
|
nid = mnb->status_change_nid; |
|
if (nid < 0) |
|
goto out; |
|
|
|
switch (action) { |
|
case MEM_GOING_ONLINE: |
|
mutex_lock(&slab_mutex); |
|
ret = init_cache_node_node(nid); |
|
mutex_unlock(&slab_mutex); |
|
break; |
|
case MEM_GOING_OFFLINE: |
|
mutex_lock(&slab_mutex); |
|
ret = drain_cache_node_node(nid); |
|
mutex_unlock(&slab_mutex); |
|
break; |
|
case MEM_ONLINE: |
|
case MEM_OFFLINE: |
|
case MEM_CANCEL_ONLINE: |
|
case MEM_CANCEL_OFFLINE: |
|
break; |
|
} |
|
out: |
|
return notifier_from_errno(ret); |
|
} |
|
#endif /* CONFIG_NUMA */ |
|
|
|
/* |
|
* swap the static kmem_cache_node with kmalloced memory |
|
*/ |
|
static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list, |
|
int nodeid) |
|
{ |
|
struct kmem_cache_node *ptr; |
|
|
|
ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid); |
|
BUG_ON(!ptr); |
|
|
|
memcpy(ptr, list, sizeof(struct kmem_cache_node)); |
|
/* |
|
* Do not assume that spinlocks can be initialized via memcpy: |
|
*/ |
|
spin_lock_init(&ptr->list_lock); |
|
|
|
MAKE_ALL_LISTS(cachep, ptr, nodeid); |
|
cachep->node[nodeid] = ptr; |
|
} |
|
|
|
/* |
|
* For setting up all the kmem_cache_node for cache whose buffer_size is same as |
|
* size of kmem_cache_node. |
|
*/ |
|
static void __init set_up_node(struct kmem_cache *cachep, int index) |
|
{ |
|
int node; |
|
|
|
for_each_online_node(node) { |
|
cachep->node[node] = &init_kmem_cache_node[index + node]; |
|
cachep->node[node]->next_reap = jiffies + |
|
REAPTIMEOUT_NODE + |
|
((unsigned long)cachep) % REAPTIMEOUT_NODE; |
|
} |
|
} |
|
|
|
/* |
|
* Initialisation. Called after the page allocator have been initialised and |
|
* before smp_init(). |
|
*/ |
|
void __init kmem_cache_init(void) |
|
{ |
|
int i; |
|
|
|
kmem_cache = &kmem_cache_boot; |
|
|
|
if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1) |
|
use_alien_caches = 0; |
|
|
|
for (i = 0; i < NUM_INIT_LISTS; i++) |
|
kmem_cache_node_init(&init_kmem_cache_node[i]); |
|
|
|
/* |
|
* Fragmentation resistance on low memory - only use bigger |
|
* page orders on machines with more than 32MB of memory if |
|
* not overridden on the command line. |
|
*/ |
|
if (!slab_max_order_set && totalram_pages() > (32 << 20) >> PAGE_SHIFT) |
|
slab_max_order = SLAB_MAX_ORDER_HI; |
|
|
|
/* Bootstrap is tricky, because several objects are allocated |
|
* from caches that do not exist yet: |
|
* 1) initialize the kmem_cache cache: it contains the struct |
|
* kmem_cache structures of all caches, except kmem_cache itself: |
|
* kmem_cache is statically allocated. |
|
* Initially an __init data area is used for the head array and the |
|
* kmem_cache_node structures, it's replaced with a kmalloc allocated |
|
* array at the end of the bootstrap. |
|
* 2) Create the first kmalloc cache. |
|
* The struct kmem_cache for the new cache is allocated normally. |
|
* An __init data area is used for the head array. |
|
* 3) Create the remaining kmalloc caches, with minimally sized |
|
* head arrays. |
|
* 4) Replace the __init data head arrays for kmem_cache and the first |
|
* kmalloc cache with kmalloc allocated arrays. |
|
* 5) Replace the __init data for kmem_cache_node for kmem_cache and |
|
* the other cache's with kmalloc allocated memory. |
|
* 6) Resize the head arrays of the kmalloc caches to their final sizes. |
|
*/ |
|
|
|
/* 1) create the kmem_cache */ |
|
|
|
/* |
|
* struct kmem_cache size depends on nr_node_ids & nr_cpu_ids |
|
*/ |
|
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); |
|
list_add(&kmem_cache->list, &slab_caches); |
|
slab_state = PARTIAL; |
|
|
|
/* |
|
* Initialize the caches that provide memory for the kmem_cache_node |
|
* structures first. Without this, further allocations will bug. |
|
*/ |
|
kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache( |
|
kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL], |
|
kmalloc_info[INDEX_NODE].size, |
|
ARCH_KMALLOC_FLAGS, 0, |
|
kmalloc_info[INDEX_NODE].size); |
|
slab_state = PARTIAL_NODE; |
|
setup_kmalloc_cache_index_table(); |
|
|
|
slab_early_init = 0; |
|
|
|
/* 5) Replace the bootstrap kmem_cache_node */ |
|
{ |
|
int nid; |
|
|
|
for_each_online_node(nid) { |
|
init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid); |
|
|
|
init_list(kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE], |
|
&init_kmem_cache_node[SIZE_NODE + nid], nid); |
|
} |
|
} |
|
|
|
create_kmalloc_caches(ARCH_KMALLOC_FLAGS); |
|
} |
|
|
|
void __init kmem_cache_init_late(void) |
|
{ |
|
struct kmem_cache *cachep; |
|
|
|
/* 6) resize the head arrays to their final sizes */ |
|
mutex_lock(&slab_mutex); |
|
list_for_each_entry(cachep, &slab_caches, list) |
|
if (enable_cpucache(cachep, GFP_NOWAIT)) |
|
BUG(); |
|
mutex_unlock(&slab_mutex); |
|
|
|
/* Done! */ |
|
slab_state = FULL; |
|
|
|
#ifdef CONFIG_NUMA |
|
/* |
|
* Register a memory hotplug callback that initializes and frees |
|
* node. |
|
*/ |
|
hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); |
|
#endif |
|
|
|
/* |
|
* The reap timers are started later, with a module init call: That part |
|
* of the kernel is not yet operational. |
|
*/ |
|
} |
|
|
|
static int __init cpucache_init(void) |
|
{ |
|
int ret; |
|
|
|
/* |
|
* Register the timers that return unneeded pages to the page allocator |
|
*/ |
|
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online", |
|
slab_online_cpu, slab_offline_cpu); |
|
WARN_ON(ret < 0); |
|
|
|
return 0; |
|
} |
|
__initcall(cpucache_init); |
|
|
|
static noinline void |
|
slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) |
|
{ |
|
#if DEBUG |
|
struct kmem_cache_node *n; |
|
unsigned long flags; |
|
int node; |
|
static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL, |
|
DEFAULT_RATELIMIT_BURST); |
|
|
|
if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs)) |
|
return; |
|
|
|
pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", |
|
nodeid, gfpflags, &gfpflags); |
|
pr_warn(" cache: %s, object size: %d, order: %d\n", |
|
cachep->name, cachep->size, cachep->gfporder); |
|
|
|
for_each_kmem_cache_node(cachep, node, n) { |
|
unsigned long total_slabs, free_slabs, free_objs; |
|
|
|
spin_lock_irqsave(&n->list_lock, flags); |
|
total_slabs = n->total_slabs; |
|
free_slabs = n->free_slabs; |
|
free_objs = n->free_objects; |
|
spin_unlock_irqrestore(&n->list_lock, flags); |
|
|
|
pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n", |
|
node, total_slabs - free_slabs, total_slabs, |
|
(total_slabs * cachep->num) - free_objs, |
|
total_slabs * cachep->num); |
|
} |
|
#endif |
|
} |
|
|
|
/* |
|
* Interface to system's page allocator. No need to hold the |
|
* kmem_cache_node ->list_lock. |
|
* |
|
* If we requested dmaable memory, we will get it. Even if we |
|
* did not request dmaable memory, we might get it, but that |
|
* would be relatively rare and ignorable. |
|
*/ |
|
static struct slab *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, |
|
int nodeid) |
|
{ |
|
struct folio *folio; |
|
struct slab *slab; |
|
|
|
flags |= cachep->allocflags; |
|
|
|
folio = (struct folio *) __alloc_pages_node(nodeid, flags, cachep->gfporder); |
|
if (!folio) { |
|
slab_out_of_memory(cachep, flags, nodeid); |
|
return NULL; |
|
} |
|
|
|
slab = folio_slab(folio); |
|
|
|
account_slab(slab, cachep->gfporder, cachep, flags); |
|
__folio_set_slab(folio); |
|
/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ |
|
if (sk_memalloc_socks() && page_is_pfmemalloc(folio_page(folio, 0))) |
|
slab_set_pfmemalloc(slab); |
|
|
|
return slab; |
|
} |
|
|
|
/* |
|
* Interface to system's page release. |
|
*/ |
|
static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
int order = cachep->gfporder; |
|
struct folio *folio = slab_folio(slab); |
|
|
|
BUG_ON(!folio_test_slab(folio)); |
|
__slab_clear_pfmemalloc(slab); |
|
__folio_clear_slab(folio); |
|
page_mapcount_reset(folio_page(folio, 0)); |
|
folio->mapping = NULL; |
|
|
|
if (current->reclaim_state) |
|
current->reclaim_state->reclaimed_slab += 1 << order; |
|
unaccount_slab(slab, order, cachep); |
|
__free_pages(folio_page(folio, 0), order); |
|
} |
|
|
|
static void kmem_rcu_free(struct rcu_head *head) |
|
{ |
|
struct kmem_cache *cachep; |
|
struct slab *slab; |
|
|
|
slab = container_of(head, struct slab, rcu_head); |
|
cachep = slab->slab_cache; |
|
|
|
kmem_freepages(cachep, slab); |
|
} |
|
|
|
#if DEBUG |
|
static bool is_debug_pagealloc_cache(struct kmem_cache *cachep) |
|
{ |
|
if (debug_pagealloc_enabled_static() && OFF_SLAB(cachep) && |
|
(cachep->size % PAGE_SIZE) == 0) |
|
return true; |
|
|
|
return false; |
|
} |
|
|
|
#ifdef CONFIG_DEBUG_PAGEALLOC |
|
static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map) |
|
{ |
|
if (!is_debug_pagealloc_cache(cachep)) |
|
return; |
|
|
|
__kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map); |
|
} |
|
|
|
#else |
|
static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp, |
|
int map) {} |
|
|
|
#endif |
|
|
|
static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) |
|
{ |
|
int size = cachep->object_size; |
|
addr = &((char *)addr)[obj_offset(cachep)]; |
|
|
|
memset(addr, val, size); |
|
*(unsigned char *)(addr + size - 1) = POISON_END; |
|
} |
|
|
|
static void dump_line(char *data, int offset, int limit) |
|
{ |
|
int i; |
|
unsigned char error = 0; |
|
int bad_count = 0; |
|
|
|
pr_err("%03x: ", offset); |
|
for (i = 0; i < limit; i++) { |
|
if (data[offset + i] != POISON_FREE) { |
|
error = data[offset + i]; |
|
bad_count++; |
|
} |
|
} |
|
print_hex_dump(KERN_CONT, "", 0, 16, 1, |
|
&data[offset], limit, 1); |
|
|
|
if (bad_count == 1) { |
|
error ^= POISON_FREE; |
|
if (!(error & (error - 1))) { |
|
pr_err("Single bit error detected. Probably bad RAM.\n"); |
|
#ifdef CONFIG_X86 |
|
pr_err("Run memtest86+ or a similar memory test tool.\n"); |
|
#else |
|
pr_err("Run a memory test tool.\n"); |
|
#endif |
|
} |
|
} |
|
} |
|
#endif |
|
|
|
#if DEBUG |
|
|
|
static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) |
|
{ |
|
int i, size; |
|
char *realobj; |
|
|
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
pr_err("Redzone: 0x%llx/0x%llx\n", |
|
*dbg_redzone1(cachep, objp), |
|
*dbg_redzone2(cachep, objp)); |
|
} |
|
|
|
if (cachep->flags & SLAB_STORE_USER) |
|
pr_err("Last user: (%pSR)\n", *dbg_userword(cachep, objp)); |
|
realobj = (char *)objp + obj_offset(cachep); |
|
size = cachep->object_size; |
|
for (i = 0; i < size && lines; i += 16, lines--) { |
|
int limit; |
|
limit = 16; |
|
if (i + limit > size) |
|
limit = size - i; |
|
dump_line(realobj, i, limit); |
|
} |
|
} |
|
|
|
static void check_poison_obj(struct kmem_cache *cachep, void *objp) |
|
{ |
|
char *realobj; |
|
int size, i; |
|
int lines = 0; |
|
|
|
if (is_debug_pagealloc_cache(cachep)) |
|
return; |
|
|
|
realobj = (char *)objp + obj_offset(cachep); |
|
size = cachep->object_size; |
|
|
|
for (i = 0; i < size; i++) { |
|
char exp = POISON_FREE; |
|
if (i == size - 1) |
|
exp = POISON_END; |
|
if (realobj[i] != exp) { |
|
int limit; |
|
/* Mismatch ! */ |
|
/* Print header */ |
|
if (lines == 0) { |
|
pr_err("Slab corruption (%s): %s start=%px, len=%d\n", |
|
print_tainted(), cachep->name, |
|
realobj, size); |
|
print_objinfo(cachep, objp, 0); |
|
} |
|
/* Hexdump the affected line */ |
|
i = (i / 16) * 16; |
|
limit = 16; |
|
if (i + limit > size) |
|
limit = size - i; |
|
dump_line(realobj, i, limit); |
|
i += 16; |
|
lines++; |
|
/* Limit to 5 lines */ |
|
if (lines > 5) |
|
break; |
|
} |
|
} |
|
if (lines != 0) { |
|
/* Print some data about the neighboring objects, if they |
|
* exist: |
|
*/ |
|
struct slab *slab = virt_to_slab(objp); |
|
unsigned int objnr; |
|
|
|
objnr = obj_to_index(cachep, slab, objp); |
|
if (objnr) { |
|
objp = index_to_obj(cachep, slab, objnr - 1); |
|
realobj = (char *)objp + obj_offset(cachep); |
|
pr_err("Prev obj: start=%px, len=%d\n", realobj, size); |
|
print_objinfo(cachep, objp, 2); |
|
} |
|
if (objnr + 1 < cachep->num) { |
|
objp = index_to_obj(cachep, slab, objnr + 1); |
|
realobj = (char *)objp + obj_offset(cachep); |
|
pr_err("Next obj: start=%px, len=%d\n", realobj, size); |
|
print_objinfo(cachep, objp, 2); |
|
} |
|
} |
|
} |
|
#endif |
|
|
|
#if DEBUG |
|
static void slab_destroy_debugcheck(struct kmem_cache *cachep, |
|
struct slab *slab) |
|
{ |
|
int i; |
|
|
|
if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) { |
|
poison_obj(cachep, slab->freelist - obj_offset(cachep), |
|
POISON_FREE); |
|
} |
|
|
|
for (i = 0; i < cachep->num; i++) { |
|
void *objp = index_to_obj(cachep, slab, i); |
|
|
|
if (cachep->flags & SLAB_POISON) { |
|
check_poison_obj(cachep, objp); |
|
slab_kernel_map(cachep, objp, 1); |
|
} |
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) |
|
slab_error(cachep, "start of a freed object was overwritten"); |
|
if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) |
|
slab_error(cachep, "end of a freed object was overwritten"); |
|
} |
|
} |
|
} |
|
#else |
|
static void slab_destroy_debugcheck(struct kmem_cache *cachep, |
|
struct slab *slab) |
|
{ |
|
} |
|
#endif |
|
|
|
/** |
|
* slab_destroy - destroy and release all objects in a slab |
|
* @cachep: cache pointer being destroyed |
|
* @slab: slab being destroyed |
|
* |
|
* Destroy all the objs in a slab, and release the mem back to the system. |
|
* Before calling the slab must have been unlinked from the cache. The |
|
* kmem_cache_node ->list_lock is not held/needed. |
|
*/ |
|
static void slab_destroy(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
void *freelist; |
|
|
|
freelist = slab->freelist; |
|
slab_destroy_debugcheck(cachep, slab); |
|
if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU)) |
|
call_rcu(&slab->rcu_head, kmem_rcu_free); |
|
else |
|
kmem_freepages(cachep, slab); |
|
|
|
/* |
|
* From now on, we don't use freelist |
|
* although actual page can be freed in rcu context |
|
*/ |
|
if (OFF_SLAB(cachep)) |
|
kfree(freelist); |
|
} |
|
|
|
/* |
|
* Update the size of the caches before calling slabs_destroy as it may |
|
* recursively call kfree. |
|
*/ |
|
static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list) |
|
{ |
|
struct slab *slab, *n; |
|
|
|
list_for_each_entry_safe(slab, n, list, slab_list) { |
|
list_del(&slab->slab_list); |
|
slab_destroy(cachep, slab); |
|
} |
|
} |
|
|
|
/** |
|
* calculate_slab_order - calculate size (page order) of slabs |
|
* @cachep: pointer to the cache that is being created |
|
* @size: size of objects to be created in this cache. |
|
* @flags: slab allocation flags |
|
* |
|
* Also calculates the number of objects per slab. |
|
* |
|
* This could be made much more intelligent. For now, try to avoid using |
|
* high order pages for slabs. When the gfp() functions are more friendly |
|
* towards high-order requests, this should be changed. |
|
* |
|
* Return: number of left-over bytes in a slab |
|
*/ |
|
static size_t calculate_slab_order(struct kmem_cache *cachep, |
|
size_t size, slab_flags_t flags) |
|
{ |
|
size_t left_over = 0; |
|
int gfporder; |
|
|
|
for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { |
|
unsigned int num; |
|
size_t remainder; |
|
|
|
num = cache_estimate(gfporder, size, flags, &remainder); |
|
if (!num) |
|
continue; |
|
|
|
/* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */ |
|
if (num > SLAB_OBJ_MAX_NUM) |
|
break; |
|
|
|
if (flags & CFLGS_OFF_SLAB) { |
|
struct kmem_cache *freelist_cache; |
|
size_t freelist_size; |
|
size_t freelist_cache_size; |
|
|
|
freelist_size = num * sizeof(freelist_idx_t); |
|
if (freelist_size > KMALLOC_MAX_CACHE_SIZE) { |
|
freelist_cache_size = PAGE_SIZE << get_order(freelist_size); |
|
} else { |
|
freelist_cache = kmalloc_slab(freelist_size, 0u); |
|
if (!freelist_cache) |
|
continue; |
|
freelist_cache_size = freelist_cache->size; |
|
|
|
/* |
|
* Needed to avoid possible looping condition |
|
* in cache_grow_begin() |
|
*/ |
|
if (OFF_SLAB(freelist_cache)) |
|
continue; |
|
} |
|
|
|
/* check if off slab has enough benefit */ |
|
if (freelist_cache_size > cachep->size / 2) |
|
continue; |
|
} |
|
|
|
/* Found something acceptable - save it away */ |
|
cachep->num = num; |
|
cachep->gfporder = gfporder; |
|
left_over = remainder; |
|
|
|
/* |
|
* A VFS-reclaimable slab tends to have most allocations |
|
* as GFP_NOFS and we really don't want to have to be allocating |
|
* higher-order pages when we are unable to shrink dcache. |
|
*/ |
|
if (flags & SLAB_RECLAIM_ACCOUNT) |
|
break; |
|
|
|
/* |
|
* Large number of objects is good, but very large slabs are |
|
* currently bad for the gfp()s. |
|
*/ |
|
if (gfporder >= slab_max_order) |
|
break; |
|
|
|
/* |
|
* Acceptable internal fragmentation? |
|
*/ |
|
if (left_over * 8 <= (PAGE_SIZE << gfporder)) |
|
break; |
|
} |
|
return left_over; |
|
} |
|
|
|
static struct array_cache __percpu *alloc_kmem_cache_cpus( |
|
struct kmem_cache *cachep, int entries, int batchcount) |
|
{ |
|
int cpu; |
|
size_t size; |
|
struct array_cache __percpu *cpu_cache; |
|
|
|
size = sizeof(void *) * entries + sizeof(struct array_cache); |
|
cpu_cache = __alloc_percpu(size, sizeof(void *)); |
|
|
|
if (!cpu_cache) |
|
return NULL; |
|
|
|
for_each_possible_cpu(cpu) { |
|
init_arraycache(per_cpu_ptr(cpu_cache, cpu), |
|
entries, batchcount); |
|
} |
|
|
|
return cpu_cache; |
|
} |
|
|
|
static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) |
|
{ |
|
if (slab_state >= FULL) |
|
return enable_cpucache(cachep, gfp); |
|
|
|
cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1); |
|
if (!cachep->cpu_cache) |
|
return 1; |
|
|
|
if (slab_state == DOWN) { |
|
/* Creation of first cache (kmem_cache). */ |
|
set_up_node(kmem_cache, CACHE_CACHE); |
|
} else if (slab_state == PARTIAL) { |
|
/* For kmem_cache_node */ |
|
set_up_node(cachep, SIZE_NODE); |
|
} else { |
|
int node; |
|
|
|
for_each_online_node(node) { |
|
cachep->node[node] = kmalloc_node( |
|
sizeof(struct kmem_cache_node), gfp, node); |
|
BUG_ON(!cachep->node[node]); |
|
kmem_cache_node_init(cachep->node[node]); |
|
} |
|
} |
|
|
|
cachep->node[numa_mem_id()]->next_reap = |
|
jiffies + REAPTIMEOUT_NODE + |
|
((unsigned long)cachep) % REAPTIMEOUT_NODE; |
|
|
|
cpu_cache_get(cachep)->avail = 0; |
|
cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; |
|
cpu_cache_get(cachep)->batchcount = 1; |
|
cpu_cache_get(cachep)->touched = 0; |
|
cachep->batchcount = 1; |
|
cachep->limit = BOOT_CPUCACHE_ENTRIES; |
|
return 0; |
|
} |
|
|
|
slab_flags_t kmem_cache_flags(unsigned int object_size, |
|
slab_flags_t flags, const char *name) |
|
{ |
|
return flags; |
|
} |
|
|
|
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 *cachep; |
|
|
|
cachep = find_mergeable(size, align, flags, name, ctor); |
|
if (cachep) { |
|
cachep->refcount++; |
|
|
|
/* |
|
* Adjust the object sizes so that we clear |
|
* the complete object on kzalloc. |
|
*/ |
|
cachep->object_size = max_t(int, cachep->object_size, size); |
|
} |
|
return cachep; |
|
} |
|
|
|
static bool set_objfreelist_slab_cache(struct kmem_cache *cachep, |
|
size_t size, slab_flags_t flags) |
|
{ |
|
size_t left; |
|
|
|
cachep->num = 0; |
|
|
|
/* |
|
* If slab auto-initialization on free is enabled, store the freelist |
|
* off-slab, so that its contents don't end up in one of the allocated |
|
* objects. |
|
*/ |
|
if (unlikely(slab_want_init_on_free(cachep))) |
|
return false; |
|
|
|
if (cachep->ctor || flags & SLAB_TYPESAFE_BY_RCU) |
|
return false; |
|
|
|
left = calculate_slab_order(cachep, size, |
|
flags | CFLGS_OBJFREELIST_SLAB); |
|
if (!cachep->num) |
|
return false; |
|
|
|
if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size) |
|
return false; |
|
|
|
cachep->colour = left / cachep->colour_off; |
|
|
|
return true; |
|
} |
|
|
|
static bool set_off_slab_cache(struct kmem_cache *cachep, |
|
size_t size, slab_flags_t flags) |
|
{ |
|
size_t left; |
|
|
|
cachep->num = 0; |
|
|
|
/* |
|
* Always use on-slab management when SLAB_NOLEAKTRACE |
|
* to avoid recursive calls into kmemleak. |
|
*/ |
|
if (flags & SLAB_NOLEAKTRACE) |
|
return false; |
|
|
|
/* |
|
* Size is large, assume best to place the slab management obj |
|
* off-slab (should allow better packing of objs). |
|
*/ |
|
left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB); |
|
if (!cachep->num) |
|
return false; |
|
|
|
/* |
|
* If the slab has been placed off-slab, and we have enough space then |
|
* move it on-slab. This is at the expense of any extra colouring. |
|
*/ |
|
if (left >= cachep->num * sizeof(freelist_idx_t)) |
|
return false; |
|
|
|
cachep->colour = left / cachep->colour_off; |
|
|
|
return true; |
|
} |
|
|
|
static bool set_on_slab_cache(struct kmem_cache *cachep, |
|
size_t size, slab_flags_t flags) |
|
{ |
|
size_t left; |
|
|
|
cachep->num = 0; |
|
|
|
left = calculate_slab_order(cachep, size, flags); |
|
if (!cachep->num) |
|
return false; |
|
|
|
cachep->colour = left / cachep->colour_off; |
|
|
|
return true; |
|
} |
|
|
|
/** |
|
* __kmem_cache_create - Create a cache. |
|
* @cachep: cache management descriptor |
|
* @flags: SLAB flags |
|
* |
|
* Returns a ptr to the cache on success, NULL on failure. |
|
* Cannot be called within an int, but can be interrupted. |
|
* The @ctor is run when new pages are allocated by the cache. |
|
* |
|
* The flags are |
|
* |
|
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) |
|
* to catch references to uninitialised memory. |
|
* |
|
* %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check |
|
* for buffer overruns. |
|
* |
|
* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware |
|
* cacheline. This can be beneficial if you're counting cycles as closely |
|
* as davem. |
|
* |
|
* Return: a pointer to the created cache or %NULL in case of error |
|
*/ |
|
int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags) |
|
{ |
|
size_t ralign = BYTES_PER_WORD; |
|
gfp_t gfp; |
|
int err; |
|
unsigned int size = cachep->size; |
|
|
|
#if DEBUG |
|
#if FORCED_DEBUG |
|
/* |
|
* Enable redzoning and last user accounting, except for caches with |
|
* large objects, if the increased size would increase the object size |
|
* above the next power of two: caches with object sizes just above a |
|
* power of two have a significant amount of internal fragmentation. |
|
*/ |
|
if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + |
|
2 * sizeof(unsigned long long))) |
|
flags |= SLAB_RED_ZONE | SLAB_STORE_USER; |
|
if (!(flags & SLAB_TYPESAFE_BY_RCU)) |
|
flags |= SLAB_POISON; |
|
#endif |
|
#endif |
|
|
|
/* |
|
* Check that size is in terms of words. This is needed to avoid |
|
* unaligned accesses for some archs when redzoning is used, and makes |
|
* sure any on-slab bufctl's are also correctly aligned. |
|
*/ |
|
size = ALIGN(size, BYTES_PER_WORD); |
|
|
|
if (flags & SLAB_RED_ZONE) { |
|
ralign = REDZONE_ALIGN; |
|
/* If redzoning, ensure that the second redzone is suitably |
|
* aligned, by adjusting the object size accordingly. */ |
|
size = ALIGN(size, REDZONE_ALIGN); |
|
} |
|
|
|
/* 3) caller mandated alignment */ |
|
if (ralign < cachep->align) { |
|
ralign = cachep->align; |
|
} |
|
/* disable debug if necessary */ |
|
if (ralign > __alignof__(unsigned long long)) |
|
flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); |
|
/* |
|
* 4) Store it. |
|
*/ |
|
cachep->align = ralign; |
|
cachep->colour_off = cache_line_size(); |
|
/* Offset must be a multiple of the alignment. */ |
|
if (cachep->colour_off < cachep->align) |
|
cachep->colour_off = cachep->align; |
|
|
|
if (slab_is_available()) |
|
gfp = GFP_KERNEL; |
|
else |
|
gfp = GFP_NOWAIT; |
|
|
|
#if DEBUG |
|
|
|
/* |
|
* Both debugging options require word-alignment which is calculated |
|
* into align above. |
|
*/ |
|
if (flags & SLAB_RED_ZONE) { |
|
/* add space for red zone words */ |
|
cachep->obj_offset += sizeof(unsigned long long); |
|
size += 2 * sizeof(unsigned long long); |
|
} |
|
if (flags & SLAB_STORE_USER) { |
|
/* user store requires one word storage behind the end of |
|
* the real object. But if the second red zone needs to be |
|
* aligned to 64 bits, we must allow that much space. |
|
*/ |
|
if (flags & SLAB_RED_ZONE) |
|
size += REDZONE_ALIGN; |
|
else |
|
size += BYTES_PER_WORD; |
|
} |
|
#endif |
|
|
|
kasan_cache_create(cachep, &size, &flags); |
|
|
|
size = ALIGN(size, cachep->align); |
|
/* |
|
* We should restrict the number of objects in a slab to implement |
|
* byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. |
|
*/ |
|
if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) |
|
size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); |
|
|
|
#if DEBUG |
|
/* |
|
* To activate debug pagealloc, off-slab management is necessary |
|
* requirement. In early phase of initialization, small sized slab |
|
* doesn't get initialized so it would not be possible. So, we need |
|
* to check size >= 256. It guarantees that all necessary small |
|
* sized slab is initialized in current slab initialization sequence. |
|
*/ |
|
if (debug_pagealloc_enabled_static() && (flags & SLAB_POISON) && |
|
size >= 256 && cachep->object_size > cache_line_size()) { |
|
if (size < PAGE_SIZE || size % PAGE_SIZE == 0) { |
|
size_t tmp_size = ALIGN(size, PAGE_SIZE); |
|
|
|
if (set_off_slab_cache(cachep, tmp_size, flags)) { |
|
flags |= CFLGS_OFF_SLAB; |
|
cachep->obj_offset += tmp_size - size; |
|
size = tmp_size; |
|
goto done; |
|
} |
|
} |
|
} |
|
#endif |
|
|
|
if (set_objfreelist_slab_cache(cachep, size, flags)) { |
|
flags |= CFLGS_OBJFREELIST_SLAB; |
|
goto done; |
|
} |
|
|
|
if (set_off_slab_cache(cachep, size, flags)) { |
|
flags |= CFLGS_OFF_SLAB; |
|
goto done; |
|
} |
|
|
|
if (set_on_slab_cache(cachep, size, flags)) |
|
goto done; |
|
|
|
return -E2BIG; |
|
|
|
done: |
|
cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); |
|
cachep->flags = flags; |
|
cachep->allocflags = __GFP_COMP; |
|
if (flags & SLAB_CACHE_DMA) |
|
cachep->allocflags |= GFP_DMA; |
|
if (flags & SLAB_CACHE_DMA32) |
|
cachep->allocflags |= GFP_DMA32; |
|
if (flags & SLAB_RECLAIM_ACCOUNT) |
|
cachep->allocflags |= __GFP_RECLAIMABLE; |
|
cachep->size = size; |
|
cachep->reciprocal_buffer_size = reciprocal_value(size); |
|
|
|
#if DEBUG |
|
/* |
|
* If we're going to use the generic kernel_map_pages() |
|
* poisoning, then it's going to smash the contents of |
|
* the redzone and userword anyhow, so switch them off. |
|
*/ |
|
if (IS_ENABLED(CONFIG_PAGE_POISONING) && |
|
(cachep->flags & SLAB_POISON) && |
|
is_debug_pagealloc_cache(cachep)) |
|
cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); |
|
#endif |
|
|
|
err = setup_cpu_cache(cachep, gfp); |
|
if (err) { |
|
__kmem_cache_release(cachep); |
|
return err; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
#if DEBUG |
|
static void check_irq_off(void) |
|
{ |
|
BUG_ON(!irqs_disabled()); |
|
} |
|
|
|
static void check_irq_on(void) |
|
{ |
|
BUG_ON(irqs_disabled()); |
|
} |
|
|
|
static void check_mutex_acquired(void) |
|
{ |
|
BUG_ON(!mutex_is_locked(&slab_mutex)); |
|
} |
|
|
|
static void check_spinlock_acquired(struct kmem_cache *cachep) |
|
{ |
|
#ifdef CONFIG_SMP |
|
check_irq_off(); |
|
assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock); |
|
#endif |
|
} |
|
|
|
static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) |
|
{ |
|
#ifdef CONFIG_SMP |
|
check_irq_off(); |
|
assert_spin_locked(&get_node(cachep, node)->list_lock); |
|
#endif |
|
} |
|
|
|
#else |
|
#define check_irq_off() do { } while(0) |
|
#define check_irq_on() do { } while(0) |
|
#define check_mutex_acquired() do { } while(0) |
|
#define check_spinlock_acquired(x) do { } while(0) |
|
#define check_spinlock_acquired_node(x, y) do { } while(0) |
|
#endif |
|
|
|
static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac, |
|
int node, bool free_all, struct list_head *list) |
|
{ |
|
int tofree; |
|
|
|
if (!ac || !ac->avail) |
|
return; |
|
|
|
tofree = free_all ? ac->avail : (ac->limit + 4) / 5; |
|
if (tofree > ac->avail) |
|
tofree = (ac->avail + 1) / 2; |
|
|
|
free_block(cachep, ac->entry, tofree, node, list); |
|
ac->avail -= tofree; |
|
memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail); |
|
} |
|
|
|
static void do_drain(void *arg) |
|
{ |
|
struct kmem_cache *cachep = arg; |
|
struct array_cache *ac; |
|
int node = numa_mem_id(); |
|
struct kmem_cache_node *n; |
|
LIST_HEAD(list); |
|
|
|
check_irq_off(); |
|
ac = cpu_cache_get(cachep); |
|
n = get_node(cachep, node); |
|
spin_lock(&n->list_lock); |
|
free_block(cachep, ac->entry, ac->avail, node, &list); |
|
spin_unlock(&n->list_lock); |
|
ac->avail = 0; |
|
slabs_destroy(cachep, &list); |
|
} |
|
|
|
static void drain_cpu_caches(struct kmem_cache *cachep) |
|
{ |
|
struct kmem_cache_node *n; |
|
int node; |
|
LIST_HEAD(list); |
|
|
|
on_each_cpu(do_drain, cachep, 1); |
|
check_irq_on(); |
|
for_each_kmem_cache_node(cachep, node, n) |
|
if (n->alien) |
|
drain_alien_cache(cachep, n->alien); |
|
|
|
for_each_kmem_cache_node(cachep, node, n) { |
|
spin_lock_irq(&n->list_lock); |
|
drain_array_locked(cachep, n->shared, node, true, &list); |
|
spin_unlock_irq(&n->list_lock); |
|
|
|
slabs_destroy(cachep, &list); |
|
} |
|
} |
|
|
|
/* |
|
* Remove slabs from the list of free slabs. |
|
* Specify the number of slabs to drain in tofree. |
|
* |
|
* Returns the actual number of slabs released. |
|
*/ |
|
static int drain_freelist(struct kmem_cache *cache, |
|
struct kmem_cache_node *n, int tofree) |
|
{ |
|
struct list_head *p; |
|
int nr_freed; |
|
struct slab *slab; |
|
|
|
nr_freed = 0; |
|
while (nr_freed < tofree && !list_empty(&n->slabs_free)) { |
|
|
|
spin_lock_irq(&n->list_lock); |
|
p = n->slabs_free.prev; |
|
if (p == &n->slabs_free) { |
|
spin_unlock_irq(&n->list_lock); |
|
goto out; |
|
} |
|
|
|
slab = list_entry(p, struct slab, slab_list); |
|
list_del(&slab->slab_list); |
|
n->free_slabs--; |
|
n->total_slabs--; |
|
/* |
|
* Safe to drop the lock. The slab is no longer linked |
|
* to the cache. |
|
*/ |
|
n->free_objects -= cache->num; |
|
spin_unlock_irq(&n->list_lock); |
|
slab_destroy(cache, slab); |
|
nr_freed++; |
|
} |
|
out: |
|
return nr_freed; |
|
} |
|
|
|
bool __kmem_cache_empty(struct kmem_cache *s) |
|
{ |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(s, node, n) |
|
if (!list_empty(&n->slabs_full) || |
|
!list_empty(&n->slabs_partial)) |
|
return false; |
|
return true; |
|
} |
|
|
|
int __kmem_cache_shrink(struct kmem_cache *cachep) |
|
{ |
|
int ret = 0; |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
drain_cpu_caches(cachep); |
|
|
|
check_irq_on(); |
|
for_each_kmem_cache_node(cachep, node, n) { |
|
drain_freelist(cachep, n, INT_MAX); |
|
|
|
ret += !list_empty(&n->slabs_full) || |
|
!list_empty(&n->slabs_partial); |
|
} |
|
return (ret ? 1 : 0); |
|
} |
|
|
|
int __kmem_cache_shutdown(struct kmem_cache *cachep) |
|
{ |
|
return __kmem_cache_shrink(cachep); |
|
} |
|
|
|
void __kmem_cache_release(struct kmem_cache *cachep) |
|
{ |
|
int i; |
|
struct kmem_cache_node *n; |
|
|
|
cache_random_seq_destroy(cachep); |
|
|
|
free_percpu(cachep->cpu_cache); |
|
|
|
/* NUMA: free the node structures */ |
|
for_each_kmem_cache_node(cachep, i, n) { |
|
kfree(n->shared); |
|
free_alien_cache(n->alien); |
|
kfree(n); |
|
cachep->node[i] = NULL; |
|
} |
|
} |
|
|
|
/* |
|
* Get the memory for a slab management obj. |
|
* |
|
* For a slab cache when the slab descriptor is off-slab, the |
|
* slab descriptor can't come from the same cache which is being created, |
|
* Because if it is the case, that means we defer the creation of |
|
* the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point. |
|
* And we eventually call down to __kmem_cache_create(), which |
|
* in turn looks up in the kmalloc_{dma,}_caches for the desired-size one. |
|
* This is a "chicken-and-egg" problem. |
|
* |
|
* So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches, |
|
* which are all initialized during kmem_cache_init(). |
|
*/ |
|
static void *alloc_slabmgmt(struct kmem_cache *cachep, |
|
struct slab *slab, int colour_off, |
|
gfp_t local_flags, int nodeid) |
|
{ |
|
void *freelist; |
|
void *addr = slab_address(slab); |
|
|
|
slab->s_mem = addr + colour_off; |
|
slab->active = 0; |
|
|
|
if (OBJFREELIST_SLAB(cachep)) |
|
freelist = NULL; |
|
else if (OFF_SLAB(cachep)) { |
|
/* Slab management obj is off-slab. */ |
|
freelist = kmalloc_node(cachep->freelist_size, |
|
local_flags, nodeid); |
|
} else { |
|
/* We will use last bytes at the slab for freelist */ |
|
freelist = addr + (PAGE_SIZE << cachep->gfporder) - |
|
cachep->freelist_size; |
|
} |
|
|
|
return freelist; |
|
} |
|
|
|
static inline freelist_idx_t get_free_obj(struct slab *slab, unsigned int idx) |
|
{ |
|
return ((freelist_idx_t *) slab->freelist)[idx]; |
|
} |
|
|
|
static inline void set_free_obj(struct slab *slab, |
|
unsigned int idx, freelist_idx_t val) |
|
{ |
|
((freelist_idx_t *)(slab->freelist))[idx] = val; |
|
} |
|
|
|
static void cache_init_objs_debug(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
#if DEBUG |
|
int i; |
|
|
|
for (i = 0; i < cachep->num; i++) { |
|
void *objp = index_to_obj(cachep, slab, i); |
|
|
|
if (cachep->flags & SLAB_STORE_USER) |
|
*dbg_userword(cachep, objp) = NULL; |
|
|
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
*dbg_redzone1(cachep, objp) = RED_INACTIVE; |
|
*dbg_redzone2(cachep, objp) = RED_INACTIVE; |
|
} |
|
/* |
|
* Constructors are not allowed to allocate memory from the same |
|
* cache which they are a constructor for. Otherwise, deadlock. |
|
* They must also be threaded. |
|
*/ |
|
if (cachep->ctor && !(cachep->flags & SLAB_POISON)) { |
|
kasan_unpoison_object_data(cachep, |
|
objp + obj_offset(cachep)); |
|
cachep->ctor(objp + obj_offset(cachep)); |
|
kasan_poison_object_data( |
|
cachep, objp + obj_offset(cachep)); |
|
} |
|
|
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) |
|
slab_error(cachep, "constructor overwrote the end of an object"); |
|
if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) |
|
slab_error(cachep, "constructor overwrote the start of an object"); |
|
} |
|
/* need to poison the objs? */ |
|
if (cachep->flags & SLAB_POISON) { |
|
poison_obj(cachep, objp, POISON_FREE); |
|
slab_kernel_map(cachep, objp, 0); |
|
} |
|
} |
|
#endif |
|
} |
|
|
|
#ifdef CONFIG_SLAB_FREELIST_RANDOM |
|
/* Hold information during a freelist initialization */ |
|
union freelist_init_state { |
|
struct { |
|
unsigned int pos; |
|
unsigned int *list; |
|
unsigned int count; |
|
}; |
|
struct rnd_state rnd_state; |
|
}; |
|
|
|
/* |
|
* Initialize the state based on the randomization method available. |
|
* return true if the pre-computed list is available, false otherwise. |
|
*/ |
|
static bool freelist_state_initialize(union freelist_init_state *state, |
|
struct kmem_cache *cachep, |
|
unsigned int count) |
|
{ |
|
bool ret; |
|
unsigned int rand; |
|
|
|
/* Use best entropy available to define a random shift */ |
|
rand = get_random_u32(); |
|
|
|
/* Use a random state if the pre-computed list is not available */ |
|
if (!cachep->random_seq) { |
|
prandom_seed_state(&state->rnd_state, rand); |
|
ret = false; |
|
} else { |
|
state->list = cachep->random_seq; |
|
state->count = count; |
|
state->pos = rand % count; |
|
ret = true; |
|
} |
|
return ret; |
|
} |
|
|
|
/* Get the next entry on the list and randomize it using a random shift */ |
|
static freelist_idx_t next_random_slot(union freelist_init_state *state) |
|
{ |
|
if (state->pos >= state->count) |
|
state->pos = 0; |
|
return state->list[state->pos++]; |
|
} |
|
|
|
/* Swap two freelist entries */ |
|
static void swap_free_obj(struct slab *slab, unsigned int a, unsigned int b) |
|
{ |
|
swap(((freelist_idx_t *) slab->freelist)[a], |
|
((freelist_idx_t *) slab->freelist)[b]); |
|
} |
|
|
|
/* |
|
* Shuffle the freelist initialization state based on pre-computed lists. |
|
* return true if the list was successfully shuffled, false otherwise. |
|
*/ |
|
static bool shuffle_freelist(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
unsigned int objfreelist = 0, i, rand, count = cachep->num; |
|
union freelist_init_state state; |
|
bool precomputed; |
|
|
|
if (count < 2) |
|
return false; |
|
|
|
precomputed = freelist_state_initialize(&state, cachep, count); |
|
|
|
/* Take a random entry as the objfreelist */ |
|
if (OBJFREELIST_SLAB(cachep)) { |
|
if (!precomputed) |
|
objfreelist = count - 1; |
|
else |
|
objfreelist = next_random_slot(&state); |
|
slab->freelist = index_to_obj(cachep, slab, objfreelist) + |
|
obj_offset(cachep); |
|
count--; |
|
} |
|
|
|
/* |
|
* On early boot, generate the list dynamically. |
|
* Later use a pre-computed list for speed. |
|
*/ |
|
if (!precomputed) { |
|
for (i = 0; i < count; i++) |
|
set_free_obj(slab, i, i); |
|
|
|
/* Fisher-Yates shuffle */ |
|
for (i = count - 1; i > 0; i--) { |
|
rand = prandom_u32_state(&state.rnd_state); |
|
rand %= (i + 1); |
|
swap_free_obj(slab, i, rand); |
|
} |
|
} else { |
|
for (i = 0; i < count; i++) |
|
set_free_obj(slab, i, next_random_slot(&state)); |
|
} |
|
|
|
if (OBJFREELIST_SLAB(cachep)) |
|
set_free_obj(slab, cachep->num - 1, objfreelist); |
|
|
|
return true; |
|
} |
|
#else |
|
static inline bool shuffle_freelist(struct kmem_cache *cachep, |
|
struct slab *slab) |
|
{ |
|
return false; |
|
} |
|
#endif /* CONFIG_SLAB_FREELIST_RANDOM */ |
|
|
|
static void cache_init_objs(struct kmem_cache *cachep, |
|
struct slab *slab) |
|
{ |
|
int i; |
|
void *objp; |
|
bool shuffled; |
|
|
|
cache_init_objs_debug(cachep, slab); |
|
|
|
/* Try to randomize the freelist if enabled */ |
|
shuffled = shuffle_freelist(cachep, slab); |
|
|
|
if (!shuffled && OBJFREELIST_SLAB(cachep)) { |
|
slab->freelist = index_to_obj(cachep, slab, cachep->num - 1) + |
|
obj_offset(cachep); |
|
} |
|
|
|
for (i = 0; i < cachep->num; i++) { |
|
objp = index_to_obj(cachep, slab, i); |
|
objp = kasan_init_slab_obj(cachep, objp); |
|
|
|
/* constructor could break poison info */ |
|
if (DEBUG == 0 && cachep->ctor) { |
|
kasan_unpoison_object_data(cachep, objp); |
|
cachep->ctor(objp); |
|
kasan_poison_object_data(cachep, objp); |
|
} |
|
|
|
if (!shuffled) |
|
set_free_obj(slab, i, i); |
|
} |
|
} |
|
|
|
static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
void *objp; |
|
|
|
objp = index_to_obj(cachep, slab, get_free_obj(slab, slab->active)); |
|
slab->active++; |
|
|
|
return objp; |
|
} |
|
|
|
static void slab_put_obj(struct kmem_cache *cachep, |
|
struct slab *slab, void *objp) |
|
{ |
|
unsigned int objnr = obj_to_index(cachep, slab, objp); |
|
#if DEBUG |
|
unsigned int i; |
|
|
|
/* Verify double free bug */ |
|
for (i = slab->active; i < cachep->num; i++) { |
|
if (get_free_obj(slab, i) == objnr) { |
|
pr_err("slab: double free detected in cache '%s', objp %px\n", |
|
cachep->name, objp); |
|
BUG(); |
|
} |
|
} |
|
#endif |
|
slab->active--; |
|
if (!slab->freelist) |
|
slab->freelist = objp + obj_offset(cachep); |
|
|
|
set_free_obj(slab, slab->active, objnr); |
|
} |
|
|
|
/* |
|
* Grow (by 1) the number of slabs within a cache. This is called by |
|
* kmem_cache_alloc() when there are no active objs left in a cache. |
|
*/ |
|
static struct slab *cache_grow_begin(struct kmem_cache *cachep, |
|
gfp_t flags, int nodeid) |
|
{ |
|
void *freelist; |
|
size_t offset; |
|
gfp_t local_flags; |
|
int slab_node; |
|
struct kmem_cache_node *n; |
|
struct slab *slab; |
|
|
|
/* |
|
* Be lazy and only check for valid flags here, keeping it out of the |
|
* critical path in kmem_cache_alloc(). |
|
*/ |
|
if (unlikely(flags & GFP_SLAB_BUG_MASK)) |
|
flags = kmalloc_fix_flags(flags); |
|
|
|
WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); |
|
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); |
|
|
|
check_irq_off(); |
|
if (gfpflags_allow_blocking(local_flags)) |
|
local_irq_enable(); |
|
|
|
/* |
|
* Get mem for the objs. Attempt to allocate a physical page from |
|
* 'nodeid'. |
|
*/ |
|
slab = kmem_getpages(cachep, local_flags, nodeid); |
|
if (!slab) |
|
goto failed; |
|
|
|
slab_node = slab_nid(slab); |
|
n = get_node(cachep, slab_node); |
|
|
|
/* Get colour for the slab, and cal the next value. */ |
|
n->colour_next++; |
|
if (n->colour_next >= cachep->colour) |
|
n->colour_next = 0; |
|
|
|
offset = n->colour_next; |
|
if (offset >= cachep->colour) |
|
offset = 0; |
|
|
|
offset *= cachep->colour_off; |
|
|
|
/* |
|
* Call kasan_poison_slab() before calling alloc_slabmgmt(), so |
|
* page_address() in the latter returns a non-tagged pointer, |
|
* as it should be for slab pages. |
|
*/ |
|
kasan_poison_slab(slab); |
|
|
|
/* Get slab management. */ |
|
freelist = alloc_slabmgmt(cachep, slab, offset, |
|
local_flags & ~GFP_CONSTRAINT_MASK, slab_node); |
|
if (OFF_SLAB(cachep) && !freelist) |
|
goto opps1; |
|
|
|
slab->slab_cache = cachep; |
|
slab->freelist = freelist; |
|
|
|
cache_init_objs(cachep, slab); |
|
|
|
if (gfpflags_allow_blocking(local_flags)) |
|
local_irq_disable(); |
|
|
|
return slab; |
|
|
|
opps1: |
|
kmem_freepages(cachep, slab); |
|
failed: |
|
if (gfpflags_allow_blocking(local_flags)) |
|
local_irq_disable(); |
|
return NULL; |
|
} |
|
|
|
static void cache_grow_end(struct kmem_cache *cachep, struct slab *slab) |
|
{ |
|
struct kmem_cache_node *n; |
|
void *list = NULL; |
|
|
|
check_irq_off(); |
|
|
|
if (!slab) |
|
return; |
|
|
|
INIT_LIST_HEAD(&slab->slab_list); |
|
n = get_node(cachep, slab_nid(slab)); |
|
|
|
spin_lock(&n->list_lock); |
|
n->total_slabs++; |
|
if (!slab->active) { |
|
list_add_tail(&slab->slab_list, &n->slabs_free); |
|
n->free_slabs++; |
|
} else |
|
fixup_slab_list(cachep, n, slab, &list); |
|
|
|
STATS_INC_GROWN(cachep); |
|
n->free_objects += cachep->num - slab->active; |
|
spin_unlock(&n->list_lock); |
|
|
|
fixup_objfreelist_debug(cachep, &list); |
|
} |
|
|
|
#if DEBUG |
|
|
|
/* |
|
* Perform extra freeing checks: |
|
* - detect bad pointers. |
|
* - POISON/RED_ZONE checking |
|
*/ |
|
static void kfree_debugcheck(const void *objp) |
|
{ |
|
if (!virt_addr_valid(objp)) { |
|
pr_err("kfree_debugcheck: out of range ptr %lxh\n", |
|
(unsigned long)objp); |
|
BUG(); |
|
} |
|
} |
|
|
|
static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) |
|
{ |
|
unsigned long long redzone1, redzone2; |
|
|
|
redzone1 = *dbg_redzone1(cache, obj); |
|
redzone2 = *dbg_redzone2(cache, obj); |
|
|
|
/* |
|
* Redzone is ok. |
|
*/ |
|
if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) |
|
return; |
|
|
|
if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) |
|
slab_error(cache, "double free detected"); |
|
else |
|
slab_error(cache, "memory outside object was overwritten"); |
|
|
|
pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n", |
|
obj, redzone1, redzone2); |
|
} |
|
|
|
static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, |
|
unsigned long caller) |
|
{ |
|
unsigned int objnr; |
|
struct slab *slab; |
|
|
|
BUG_ON(virt_to_cache(objp) != cachep); |
|
|
|
objp -= obj_offset(cachep); |
|
kfree_debugcheck(objp); |
|
slab = virt_to_slab(objp); |
|
|
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
verify_redzone_free(cachep, objp); |
|
*dbg_redzone1(cachep, objp) = RED_INACTIVE; |
|
*dbg_redzone2(cachep, objp) = RED_INACTIVE; |
|
} |
|
if (cachep->flags & SLAB_STORE_USER) |
|
*dbg_userword(cachep, objp) = (void *)caller; |
|
|
|
objnr = obj_to_index(cachep, slab, objp); |
|
|
|
BUG_ON(objnr >= cachep->num); |
|
BUG_ON(objp != index_to_obj(cachep, slab, objnr)); |
|
|
|
if (cachep->flags & SLAB_POISON) { |
|
poison_obj(cachep, objp, POISON_FREE); |
|
slab_kernel_map(cachep, objp, 0); |
|
} |
|
return objp; |
|
} |
|
|
|
#else |
|
#define kfree_debugcheck(x) do { } while(0) |
|
#define cache_free_debugcheck(x, objp, z) (objp) |
|
#endif |
|
|
|
static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, |
|
void **list) |
|
{ |
|
#if DEBUG |
|
void *next = *list; |
|
void *objp; |
|
|
|
while (next) { |
|
objp = next - obj_offset(cachep); |
|
next = *(void **)next; |
|
poison_obj(cachep, objp, POISON_FREE); |
|
} |
|
#endif |
|
} |
|
|
|
static inline void fixup_slab_list(struct kmem_cache *cachep, |
|
struct kmem_cache_node *n, struct slab *slab, |
|
void **list) |
|
{ |
|
/* move slabp to correct slabp list: */ |
|
list_del(&slab->slab_list); |
|
if (slab->active == cachep->num) { |
|
list_add(&slab->slab_list, &n->slabs_full); |
|
if (OBJFREELIST_SLAB(cachep)) { |
|
#if DEBUG |
|
/* Poisoning will be done without holding the lock */ |
|
if (cachep->flags & SLAB_POISON) { |
|
void **objp = slab->freelist; |
|
|
|
*objp = *list; |
|
*list = objp; |
|
} |
|
#endif |
|
slab->freelist = NULL; |
|
} |
|
} else |
|
list_add(&slab->slab_list, &n->slabs_partial); |
|
} |
|
|
|
/* Try to find non-pfmemalloc slab if needed */ |
|
static noinline struct slab *get_valid_first_slab(struct kmem_cache_node *n, |
|
struct slab *slab, bool pfmemalloc) |
|
{ |
|
if (!slab) |
|
return NULL; |
|
|
|
if (pfmemalloc) |
|
return slab; |
|
|
|
if (!slab_test_pfmemalloc(slab)) |
|
return slab; |
|
|
|
/* No need to keep pfmemalloc slab if we have enough free objects */ |
|
if (n->free_objects > n->free_limit) { |
|
slab_clear_pfmemalloc(slab); |
|
return slab; |
|
} |
|
|
|
/* Move pfmemalloc slab to the end of list to speed up next search */ |
|
list_del(&slab->slab_list); |
|
if (!slab->active) { |
|
list_add_tail(&slab->slab_list, &n->slabs_free); |
|
n->free_slabs++; |
|
} else |
|
list_add_tail(&slab->slab_list, &n->slabs_partial); |
|
|
|
list_for_each_entry(slab, &n->slabs_partial, slab_list) { |
|
if (!slab_test_pfmemalloc(slab)) |
|
return slab; |
|
} |
|
|
|
n->free_touched = 1; |
|
list_for_each_entry(slab, &n->slabs_free, slab_list) { |
|
if (!slab_test_pfmemalloc(slab)) { |
|
n->free_slabs--; |
|
return slab; |
|
} |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
static struct slab *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc) |
|
{ |
|
struct slab *slab; |
|
|
|
assert_spin_locked(&n->list_lock); |
|
slab = list_first_entry_or_null(&n->slabs_partial, struct slab, |
|
slab_list); |
|
if (!slab) { |
|
n->free_touched = 1; |
|
slab = list_first_entry_or_null(&n->slabs_free, struct slab, |
|
slab_list); |
|
if (slab) |
|
n->free_slabs--; |
|
} |
|
|
|
if (sk_memalloc_socks()) |
|
slab = get_valid_first_slab(n, slab, pfmemalloc); |
|
|
|
return slab; |
|
} |
|
|
|
static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, |
|
struct kmem_cache_node *n, gfp_t flags) |
|
{ |
|
struct slab *slab; |
|
void *obj; |
|
void *list = NULL; |
|
|
|
if (!gfp_pfmemalloc_allowed(flags)) |
|
return NULL; |
|
|
|
spin_lock(&n->list_lock); |
|
slab = get_first_slab(n, true); |
|
if (!slab) { |
|
spin_unlock(&n->list_lock); |
|
return NULL; |
|
} |
|
|
|
obj = slab_get_obj(cachep, slab); |
|
n->free_objects--; |
|
|
|
fixup_slab_list(cachep, n, slab, &list); |
|
|
|
spin_unlock(&n->list_lock); |
|
fixup_objfreelist_debug(cachep, &list); |
|
|
|
return obj; |
|
} |
|
|
|
/* |
|
* Slab list should be fixed up by fixup_slab_list() for existing slab |
|
* or cache_grow_end() for new slab |
|
*/ |
|
static __always_inline int alloc_block(struct kmem_cache *cachep, |
|
struct array_cache *ac, struct slab *slab, int batchcount) |
|
{ |
|
/* |
|
* There must be at least one object available for |
|
* allocation. |
|
*/ |
|
BUG_ON(slab->active >= cachep->num); |
|
|
|
while (slab->active < cachep->num && batchcount--) { |
|
STATS_INC_ALLOCED(cachep); |
|
STATS_INC_ACTIVE(cachep); |
|
STATS_SET_HIGH(cachep); |
|
|
|
ac->entry[ac->avail++] = slab_get_obj(cachep, slab); |
|
} |
|
|
|
return batchcount; |
|
} |
|
|
|
static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) |
|
{ |
|
int batchcount; |
|
struct kmem_cache_node *n; |
|
struct array_cache *ac, *shared; |
|
int node; |
|
void *list = NULL; |
|
struct slab *slab; |
|
|
|
check_irq_off(); |
|
node = numa_mem_id(); |
|
|
|
ac = cpu_cache_get(cachep); |
|
batchcount = ac->batchcount; |
|
if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { |
|
/* |
|
* If there was little recent activity on this cache, then |
|
* perform only a partial refill. Otherwise we could generate |
|
* refill bouncing. |
|
*/ |
|
batchcount = BATCHREFILL_LIMIT; |
|
} |
|
n = get_node(cachep, node); |
|
|
|
BUG_ON(ac->avail > 0 || !n); |
|
shared = READ_ONCE(n->shared); |
|
if (!n->free_objects && (!shared || !shared->avail)) |
|
goto direct_grow; |
|
|
|
spin_lock(&n->list_lock); |
|
shared = READ_ONCE(n->shared); |
|
|
|
/* See if we can refill from the shared array */ |
|
if (shared && transfer_objects(ac, shared, batchcount)) { |
|
shared->touched = 1; |
|
goto alloc_done; |
|
} |
|
|
|
while (batchcount > 0) { |
|
/* Get slab alloc is to come from. */ |
|
slab = get_first_slab(n, false); |
|
if (!slab) |
|
goto must_grow; |
|
|
|
check_spinlock_acquired(cachep); |
|
|
|
batchcount = alloc_block(cachep, ac, slab, batchcount); |
|
fixup_slab_list(cachep, n, slab, &list); |
|
} |
|
|
|
must_grow: |
|
n->free_objects -= ac->avail; |
|
alloc_done: |
|
spin_unlock(&n->list_lock); |
|
fixup_objfreelist_debug(cachep, &list); |
|
|
|
direct_grow: |
|
if (unlikely(!ac->avail)) { |
|
/* Check if we can use obj in pfmemalloc slab */ |
|
if (sk_memalloc_socks()) { |
|
void *obj = cache_alloc_pfmemalloc(cachep, n, flags); |
|
|
|
if (obj) |
|
return obj; |
|
} |
|
|
|
slab = cache_grow_begin(cachep, gfp_exact_node(flags), node); |
|
|
|
/* |
|
* cache_grow_begin() can reenable interrupts, |
|
* then ac could change. |
|
*/ |
|
ac = cpu_cache_get(cachep); |
|
if (!ac->avail && slab) |
|
alloc_block(cachep, ac, slab, batchcount); |
|
cache_grow_end(cachep, slab); |
|
|
|
if (!ac->avail) |
|
return NULL; |
|
} |
|
ac->touched = 1; |
|
|
|
return ac->entry[--ac->avail]; |
|
} |
|
|
|
#if DEBUG |
|
static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, |
|
gfp_t flags, void *objp, unsigned long caller) |
|
{ |
|
WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); |
|
if (!objp || is_kfence_address(objp)) |
|
return objp; |
|
if (cachep->flags & SLAB_POISON) { |
|
check_poison_obj(cachep, objp); |
|
slab_kernel_map(cachep, objp, 1); |
|
poison_obj(cachep, objp, POISON_INUSE); |
|
} |
|
if (cachep->flags & SLAB_STORE_USER) |
|
*dbg_userword(cachep, objp) = (void *)caller; |
|
|
|
if (cachep->flags & SLAB_RED_ZONE) { |
|
if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || |
|
*dbg_redzone2(cachep, objp) != RED_INACTIVE) { |
|
slab_error(cachep, "double free, or memory outside object was overwritten"); |
|
pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n", |
|
objp, *dbg_redzone1(cachep, objp), |
|
*dbg_redzone2(cachep, objp)); |
|
} |
|
*dbg_redzone1(cachep, objp) = RED_ACTIVE; |
|
*dbg_redzone2(cachep, objp) = RED_ACTIVE; |
|
} |
|
|
|
objp += obj_offset(cachep); |
|
if (cachep->ctor && cachep->flags & SLAB_POISON) |
|
cachep->ctor(objp); |
|
if ((unsigned long)objp & (arch_slab_minalign() - 1)) { |
|
pr_err("0x%px: not aligned to arch_slab_minalign()=%u\n", objp, |
|
arch_slab_minalign()); |
|
} |
|
return objp; |
|
} |
|
#else |
|
#define cache_alloc_debugcheck_after(a, b, objp, d) (objp) |
|
#endif |
|
|
|
static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) |
|
{ |
|
void *objp; |
|
struct array_cache *ac; |
|
|
|
check_irq_off(); |
|
|
|
ac = cpu_cache_get(cachep); |
|
if (likely(ac->avail)) { |
|
ac->touched = 1; |
|
objp = ac->entry[--ac->avail]; |
|
|
|
STATS_INC_ALLOCHIT(cachep); |
|
goto out; |
|
} |
|
|
|
STATS_INC_ALLOCMISS(cachep); |
|
objp = cache_alloc_refill(cachep, flags); |
|
/* |
|
* the 'ac' may be updated by cache_alloc_refill(), |
|
* and kmemleak_erase() requires its correct value. |
|
*/ |
|
ac = cpu_cache_get(cachep); |
|
|
|
out: |
|
/* |
|
* To avoid a false negative, if an object that is in one of the |
|
* per-CPU caches is leaked, we need to make sure kmemleak doesn't |
|
* treat the array pointers as a reference to the object. |
|
*/ |
|
if (objp) |
|
kmemleak_erase(&ac->entry[ac->avail]); |
|
return objp; |
|
} |
|
|
|
#ifdef CONFIG_NUMA |
|
static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); |
|
|
|
/* |
|
* Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set. |
|
* |
|
* If we are in_interrupt, then process context, including cpusets and |
|
* mempolicy, may not apply and should not be used for allocation policy. |
|
*/ |
|
static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) |
|
{ |
|
int nid_alloc, nid_here; |
|
|
|
if (in_interrupt() || (flags & __GFP_THISNODE)) |
|
return NULL; |
|
nid_alloc = nid_here = numa_mem_id(); |
|
if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) |
|
nid_alloc = cpuset_slab_spread_node(); |
|
else if (current->mempolicy) |
|
nid_alloc = mempolicy_slab_node(); |
|
if (nid_alloc != nid_here) |
|
return ____cache_alloc_node(cachep, flags, nid_alloc); |
|
return NULL; |
|
} |
|
|
|
/* |
|
* Fallback function if there was no memory available and no objects on a |
|
* certain node and fall back is permitted. First we scan all the |
|
* available node for available objects. If that fails then we |
|
* perform an allocation without specifying a node. This allows the page |
|
* allocator to do its reclaim / fallback magic. We then insert the |
|
* slab into the proper nodelist and then allocate from it. |
|
*/ |
|
static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) |
|
{ |
|
struct zonelist *zonelist; |
|
struct zoneref *z; |
|
struct zone *zone; |
|
enum zone_type highest_zoneidx = gfp_zone(flags); |
|
void *obj = NULL; |
|
struct slab *slab; |
|
int nid; |
|
unsigned int cpuset_mems_cookie; |
|
|
|
if (flags & __GFP_THISNODE) |
|
return NULL; |
|
|
|
retry_cpuset: |
|
cpuset_mems_cookie = read_mems_allowed_begin(); |
|
zonelist = node_zonelist(mempolicy_slab_node(), flags); |
|
|
|
retry: |
|
/* |
|
* Look through allowed nodes for objects available |
|
* from existing per node queues. |
|
*/ |
|
for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) { |
|
nid = zone_to_nid(zone); |
|
|
|
if (cpuset_zone_allowed(zone, flags) && |
|
get_node(cache, nid) && |
|
get_node(cache, nid)->free_objects) { |
|
obj = ____cache_alloc_node(cache, |
|
gfp_exact_node(flags), nid); |
|
if (obj) |
|
break; |
|
} |
|
} |
|
|
|
if (!obj) { |
|
/* |
|
* This allocation will be performed within the constraints |
|
* of the current cpuset / memory policy requirements. |
|
* We may trigger various forms of reclaim on the allowed |
|
* set and go into memory reserves if necessary. |
|
*/ |
|
slab = cache_grow_begin(cache, flags, numa_mem_id()); |
|
cache_grow_end(cache, slab); |
|
if (slab) { |
|
nid = slab_nid(slab); |
|
obj = ____cache_alloc_node(cache, |
|
gfp_exact_node(flags), nid); |
|
|
|
/* |
|
* Another processor may allocate the objects in |
|
* the slab since we are not holding any locks. |
|
*/ |
|
if (!obj) |
|
goto retry; |
|
} |
|
} |
|
|
|
if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie))) |
|
goto retry_cpuset; |
|
return obj; |
|
} |
|
|
|
/* |
|
* An interface to enable slab creation on nodeid |
|
*/ |
|
static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, |
|
int nodeid) |
|
{ |
|
struct slab *slab; |
|
struct kmem_cache_node *n; |
|
void *obj = NULL; |
|
void *list = NULL; |
|
|
|
VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES); |
|
n = get_node(cachep, nodeid); |
|
BUG_ON(!n); |
|
|
|
check_irq_off(); |
|
spin_lock(&n->list_lock); |
|
slab = get_first_slab(n, false); |
|
if (!slab) |
|
goto must_grow; |
|
|
|
check_spinlock_acquired_node(cachep, nodeid); |
|
|
|
STATS_INC_NODEALLOCS(cachep); |
|
STATS_INC_ACTIVE(cachep); |
|
STATS_SET_HIGH(cachep); |
|
|
|
BUG_ON(slab->active == cachep->num); |
|
|
|
obj = slab_get_obj(cachep, slab); |
|
n->free_objects--; |
|
|
|
fixup_slab_list(cachep, n, slab, &list); |
|
|
|
spin_unlock(&n->list_lock); |
|
fixup_objfreelist_debug(cachep, &list); |
|
return obj; |
|
|
|
must_grow: |
|
spin_unlock(&n->list_lock); |
|
slab = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid); |
|
if (slab) { |
|
/* This slab isn't counted yet so don't update free_objects */ |
|
obj = slab_get_obj(cachep, slab); |
|
} |
|
cache_grow_end(cachep, slab); |
|
|
|
return obj ? obj : fallback_alloc(cachep, flags); |
|
} |
|
|
|
static __always_inline void * |
|
__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags, int nodeid) |
|
{ |
|
void *objp = NULL; |
|
int slab_node = numa_mem_id(); |
|
|
|
if (nodeid == NUMA_NO_NODE) { |
|
if (current->mempolicy || cpuset_do_slab_mem_spread()) { |
|
objp = alternate_node_alloc(cachep, flags); |
|
if (objp) |
|
goto out; |
|
} |
|
/* |
|
* Use the locally cached objects if possible. |
|
* However ____cache_alloc does not allow fallback |
|
* to other nodes. It may fail while we still have |
|
* objects on other nodes available. |
|
*/ |
|
objp = ____cache_alloc(cachep, flags); |
|
nodeid = slab_node; |
|
} else if (nodeid == slab_node) { |
|
objp = ____cache_alloc(cachep, flags); |
|
} else if (!get_node(cachep, nodeid)) { |
|
/* Node not bootstrapped yet */ |
|
objp = fallback_alloc(cachep, flags); |
|
goto out; |
|
} |
|
|
|
/* |
|
* We may just have run out of memory on the local node. |
|
* ____cache_alloc_node() knows how to locate memory on other nodes |
|
*/ |
|
if (!objp) |
|
objp = ____cache_alloc_node(cachep, flags, nodeid); |
|
out: |
|
return objp; |
|
} |
|
#else |
|
|
|
static __always_inline void * |
|
__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags, int nodeid __maybe_unused) |
|
{ |
|
return ____cache_alloc(cachep, flags); |
|
} |
|
|
|
#endif /* CONFIG_NUMA */ |
|
|
|
static __always_inline void * |
|
slab_alloc_node(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags, |
|
int nodeid, size_t orig_size, unsigned long caller) |
|
{ |
|
unsigned long save_flags; |
|
void *objp; |
|
struct obj_cgroup *objcg = NULL; |
|
bool init = false; |
|
|
|
flags &= gfp_allowed_mask; |
|
cachep = slab_pre_alloc_hook(cachep, lru, &objcg, 1, flags); |
|
if (unlikely(!cachep)) |
|
return NULL; |
|
|
|
objp = kfence_alloc(cachep, orig_size, flags); |
|
if (unlikely(objp)) |
|
goto out; |
|
|
|
local_irq_save(save_flags); |
|
objp = __do_cache_alloc(cachep, flags, nodeid); |
|
local_irq_restore(save_flags); |
|
objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); |
|
prefetchw(objp); |
|
init = slab_want_init_on_alloc(flags, cachep); |
|
|
|
out: |
|
slab_post_alloc_hook(cachep, objcg, flags, 1, &objp, init); |
|
return objp; |
|
} |
|
|
|
static __always_inline void * |
|
slab_alloc(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags, |
|
size_t orig_size, unsigned long caller) |
|
{ |
|
return slab_alloc_node(cachep, lru, flags, NUMA_NO_NODE, orig_size, |
|
caller); |
|
} |
|
|
|
/* |
|
* Caller needs to acquire correct kmem_cache_node's list_lock |
|
* @list: List of detached free slabs should be freed by caller |
|
*/ |
|
static void free_block(struct kmem_cache *cachep, void **objpp, |
|
int nr_objects, int node, struct list_head *list) |
|
{ |
|
int i; |
|
struct kmem_cache_node *n = get_node(cachep, node); |
|
struct slab *slab; |
|
|
|
n->free_objects += nr_objects; |
|
|
|
for (i = 0; i < nr_objects; i++) { |
|
void *objp; |
|
struct slab *slab; |
|
|
|
objp = objpp[i]; |
|
|
|
slab = virt_to_slab(objp); |
|
list_del(&slab->slab_list); |
|
check_spinlock_acquired_node(cachep, node); |
|
slab_put_obj(cachep, slab, objp); |
|
STATS_DEC_ACTIVE(cachep); |
|
|
|
/* fixup slab chains */ |
|
if (slab->active == 0) { |
|
list_add(&slab->slab_list, &n->slabs_free); |
|
n->free_slabs++; |
|
} else { |
|
/* Unconditionally move a slab to the end of the |
|
* partial list on free - maximum time for the |
|
* other objects to be freed, too. |
|
*/ |
|
list_add_tail(&slab->slab_list, &n->slabs_partial); |
|
} |
|
} |
|
|
|
while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) { |
|
n->free_objects -= cachep->num; |
|
|
|
slab = list_last_entry(&n->slabs_free, struct slab, slab_list); |
|
list_move(&slab->slab_list, list); |
|
n->free_slabs--; |
|
n->total_slabs--; |
|
} |
|
} |
|
|
|
static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) |
|
{ |
|
int batchcount; |
|
struct kmem_cache_node *n; |
|
int node = numa_mem_id(); |
|
LIST_HEAD(list); |
|
|
|
batchcount = ac->batchcount; |
|
|
|
check_irq_off(); |
|
n = get_node(cachep, node); |
|
spin_lock(&n->list_lock); |
|
if (n->shared) { |
|
struct array_cache *shared_array = n->shared; |
|
int max = shared_array->limit - shared_array->avail; |
|
if (max) { |
|
if (batchcount > max) |
|
batchcount = max; |
|
memcpy(&(shared_array->entry[shared_array->avail]), |
|
ac->entry, sizeof(void *) * batchcount); |
|
shared_array->avail += batchcount; |
|
goto free_done; |
|
} |
|
} |
|
|
|
free_block(cachep, ac->entry, batchcount, node, &list); |
|
free_done: |
|
#if STATS |
|
{ |
|
int i = 0; |
|
struct slab *slab; |
|
|
|
list_for_each_entry(slab, &n->slabs_free, slab_list) { |
|
BUG_ON(slab->active); |
|
|
|
i++; |
|
} |
|
STATS_SET_FREEABLE(cachep, i); |
|
} |
|
#endif |
|
spin_unlock(&n->list_lock); |
|
ac->avail -= batchcount; |
|
memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); |
|
slabs_destroy(cachep, &list); |
|
} |
|
|
|
/* |
|
* Release an obj back to its cache. If the obj has a constructed state, it must |
|
* be in this state _before_ it is released. Called with disabled ints. |
|
*/ |
|
static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, |
|
unsigned long caller) |
|
{ |
|
bool init; |
|
|
|
memcg_slab_free_hook(cachep, virt_to_slab(objp), &objp, 1); |
|
|
|
if (is_kfence_address(objp)) { |
|
kmemleak_free_recursive(objp, cachep->flags); |
|
__kfence_free(objp); |
|
return; |
|
} |
|
|
|
/* |
|
* As memory initialization might be integrated into KASAN, |
|
* kasan_slab_free and initialization memset must be |
|
* kept together to avoid discrepancies in behavior. |
|
*/ |
|
init = slab_want_init_on_free(cachep); |
|
if (init && !kasan_has_integrated_init()) |
|
memset(objp, 0, cachep->object_size); |
|
/* KASAN might put objp into memory quarantine, delaying its reuse. */ |
|
if (kasan_slab_free(cachep, objp, init)) |
|
return; |
|
|
|
/* Use KCSAN to help debug racy use-after-free. */ |
|
if (!(cachep->flags & SLAB_TYPESAFE_BY_RCU)) |
|
__kcsan_check_access(objp, cachep->object_size, |
|
KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT); |
|
|
|
___cache_free(cachep, objp, caller); |
|
} |
|
|
|
void ___cache_free(struct kmem_cache *cachep, void *objp, |
|
unsigned long caller) |
|
{ |
|
struct array_cache *ac = cpu_cache_get(cachep); |
|
|
|
check_irq_off(); |
|
kmemleak_free_recursive(objp, cachep->flags); |
|
objp = cache_free_debugcheck(cachep, objp, caller); |
|
|
|
/* |
|
* Skip calling cache_free_alien() when the platform is not numa. |
|
* This will avoid cache misses that happen while accessing slabp (which |
|
* is per page memory reference) to get nodeid. Instead use a global |
|
* variable to skip the call, which is mostly likely to be present in |
|
* the cache. |
|
*/ |
|
if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) |
|
return; |
|
|
|
if (ac->avail < ac->limit) { |
|
STATS_INC_FREEHIT(cachep); |
|
} else { |
|
STATS_INC_FREEMISS(cachep); |
|
cache_flusharray(cachep, ac); |
|
} |
|
|
|
if (sk_memalloc_socks()) { |
|
struct slab *slab = virt_to_slab(objp); |
|
|
|
if (unlikely(slab_test_pfmemalloc(slab))) { |
|
cache_free_pfmemalloc(cachep, slab, objp); |
|
return; |
|
} |
|
} |
|
|
|
__free_one(ac, objp); |
|
} |
|
|
|
static __always_inline |
|
void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru, |
|
gfp_t flags) |
|
{ |
|
void *ret = slab_alloc(cachep, lru, flags, cachep->object_size, _RET_IP_); |
|
|
|
trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, NUMA_NO_NODE); |
|
|
|
return ret; |
|
} |
|
|
|
/** |
|
* kmem_cache_alloc - Allocate an object |
|
* @cachep: The cache to allocate from. |
|
* @flags: See kmalloc(). |
|
* |
|
* Allocate an object from this cache. The flags are only relevant |
|
* if the cache has no available objects. |
|
* |
|
* Return: pointer to the new object or %NULL in case of error |
|
*/ |
|
void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) |
|
{ |
|
return __kmem_cache_alloc_lru(cachep, NULL, flags); |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc); |
|
|
|
void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru, |
|
gfp_t flags) |
|
{ |
|
return __kmem_cache_alloc_lru(cachep, lru, flags); |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_lru); |
|
|
|
static __always_inline void |
|
cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags, |
|
size_t size, void **p, unsigned long caller) |
|
{ |
|
size_t i; |
|
|
|
for (i = 0; i < size; i++) |
|
p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller); |
|
} |
|
|
|
int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, |
|
void **p) |
|
{ |
|
size_t i; |
|
struct obj_cgroup *objcg = NULL; |
|
|
|
s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags); |
|
if (!s) |
|
return 0; |
|
|
|
local_irq_disable(); |
|
for (i = 0; i < size; i++) { |
|
void *objp = kfence_alloc(s, s->object_size, flags) ?: |
|
__do_cache_alloc(s, flags, NUMA_NO_NODE); |
|
|
|
if (unlikely(!objp)) |
|
goto error; |
|
p[i] = objp; |
|
} |
|
local_irq_enable(); |
|
|
|
cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_); |
|
|
|
/* |
|
* memcg and kmem_cache debug support and memory initialization. |
|
* Done outside of the IRQ disabled section. |
|
*/ |
|
slab_post_alloc_hook(s, objcg, flags, size, p, |
|
slab_want_init_on_alloc(flags, s)); |
|
/* FIXME: Trace call missing. Christoph would like a bulk variant */ |
|
return size; |
|
error: |
|
local_irq_enable(); |
|
cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_); |
|
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); |
|
|
|
/** |
|
* kmem_cache_alloc_node - Allocate an object on the specified node |
|
* @cachep: The cache to allocate from. |
|
* @flags: See kmalloc(). |
|
* @nodeid: node number of the target node. |
|
* |
|
* Identical to kmem_cache_alloc but it will allocate memory on the given |
|
* node, which can improve the performance for cpu bound structures. |
|
* |
|
* Fallback to other node is possible if __GFP_THISNODE is not set. |
|
* |
|
* Return: pointer to the new object or %NULL in case of error |
|
*/ |
|
void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) |
|
{ |
|
void *ret = slab_alloc_node(cachep, NULL, flags, nodeid, cachep->object_size, _RET_IP_); |
|
|
|
trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, nodeid); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(kmem_cache_alloc_node); |
|
|
|
void *__kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, |
|
int nodeid, size_t orig_size, |
|
unsigned long caller) |
|
{ |
|
return slab_alloc_node(cachep, NULL, flags, nodeid, |
|
orig_size, caller); |
|
} |
|
|
|
#ifdef CONFIG_PRINTK |
|
void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) |
|
{ |
|
struct kmem_cache *cachep; |
|
unsigned int objnr; |
|
void *objp; |
|
|
|
kpp->kp_ptr = object; |
|
kpp->kp_slab = slab; |
|
cachep = slab->slab_cache; |
|
kpp->kp_slab_cache = cachep; |
|
objp = object - obj_offset(cachep); |
|
kpp->kp_data_offset = obj_offset(cachep); |
|
slab = virt_to_slab(objp); |
|
objnr = obj_to_index(cachep, slab, objp); |
|
objp = index_to_obj(cachep, slab, objnr); |
|
kpp->kp_objp = objp; |
|
if (DEBUG && cachep->flags & SLAB_STORE_USER) |
|
kpp->kp_ret = *dbg_userword(cachep, objp); |
|
} |
|
#endif |
|
|
|
static __always_inline |
|
void __do_kmem_cache_free(struct kmem_cache *cachep, void *objp, |
|
unsigned long caller) |
|
{ |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
debug_check_no_locks_freed(objp, cachep->object_size); |
|
if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) |
|
debug_check_no_obj_freed(objp, cachep->object_size); |
|
__cache_free(cachep, objp, caller); |
|
local_irq_restore(flags); |
|
} |
|
|
|
void __kmem_cache_free(struct kmem_cache *cachep, void *objp, |
|
unsigned long caller) |
|
{ |
|
__do_kmem_cache_free(cachep, objp, caller); |
|
} |
|
|
|
/** |
|
* kmem_cache_free - Deallocate an object |
|
* @cachep: The cache the allocation was from. |
|
* @objp: The previously allocated object. |
|
* |
|
* Free an object which was previously allocated from this |
|
* cache. |
|
*/ |
|
void kmem_cache_free(struct kmem_cache *cachep, void *objp) |
|
{ |
|
cachep = cache_from_obj(cachep, objp); |
|
if (!cachep) |
|
return; |
|
|
|
trace_kmem_cache_free(_RET_IP_, objp, cachep); |
|
__do_kmem_cache_free(cachep, objp, _RET_IP_); |
|
} |
|
EXPORT_SYMBOL(kmem_cache_free); |
|
|
|
void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) |
|
{ |
|
|
|
local_irq_disable(); |
|
for (int i = 0; i < size; i++) { |
|
void *objp = p[i]; |
|
struct kmem_cache *s; |
|
|
|
if (!orig_s) { |
|
struct folio *folio = virt_to_folio(objp); |
|
|
|
/* called via kfree_bulk */ |
|
if (!folio_test_slab(folio)) { |
|
local_irq_enable(); |
|
free_large_kmalloc(folio, objp); |
|
local_irq_disable(); |
|
continue; |
|
} |
|
s = folio_slab(folio)->slab_cache; |
|
} else { |
|
s = cache_from_obj(orig_s, objp); |
|
} |
|
|
|
if (!s) |
|
continue; |
|
|
|
debug_check_no_locks_freed(objp, s->object_size); |
|
if (!(s->flags & SLAB_DEBUG_OBJECTS)) |
|
debug_check_no_obj_freed(objp, s->object_size); |
|
|
|
__cache_free(s, objp, _RET_IP_); |
|
} |
|
local_irq_enable(); |
|
|
|
/* FIXME: add tracing */ |
|
} |
|
EXPORT_SYMBOL(kmem_cache_free_bulk); |
|
|
|
/* |
|
* This initializes kmem_cache_node or resizes various caches for all nodes. |
|
*/ |
|
static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp) |
|
{ |
|
int ret; |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_online_node(node) { |
|
ret = setup_kmem_cache_node(cachep, node, gfp, true); |
|
if (ret) |
|
goto fail; |
|
|
|
} |
|
|
|
return 0; |
|
|
|
fail: |
|
if (!cachep->list.next) { |
|
/* Cache is not active yet. Roll back what we did */ |
|
node--; |
|
while (node >= 0) { |
|
n = get_node(cachep, node); |
|
if (n) { |
|
kfree(n->shared); |
|
free_alien_cache(n->alien); |
|
kfree(n); |
|
cachep->node[node] = NULL; |
|
} |
|
node--; |
|
} |
|
} |
|
return -ENOMEM; |
|
} |
|
|
|
/* Always called with the slab_mutex held */ |
|
static int do_tune_cpucache(struct kmem_cache *cachep, int limit, |
|
int batchcount, int shared, gfp_t gfp) |
|
{ |
|
struct array_cache __percpu *cpu_cache, *prev; |
|
int cpu; |
|
|
|
cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount); |
|
if (!cpu_cache) |
|
return -ENOMEM; |
|
|
|
prev = cachep->cpu_cache; |
|
cachep->cpu_cache = cpu_cache; |
|
/* |
|
* Without a previous cpu_cache there's no need to synchronize remote |
|
* cpus, so skip the IPIs. |
|
*/ |
|
if (prev) |
|
kick_all_cpus_sync(); |
|
|
|
check_irq_on(); |
|
cachep->batchcount = batchcount; |
|
cachep->limit = limit; |
|
cachep->shared = shared; |
|
|
|
if (!prev) |
|
goto setup_node; |
|
|
|
for_each_online_cpu(cpu) { |
|
LIST_HEAD(list); |
|
int node; |
|
struct kmem_cache_node *n; |
|
struct array_cache *ac = per_cpu_ptr(prev, cpu); |
|
|
|
node = cpu_to_mem(cpu); |
|
n = get_node(cachep, node); |
|
spin_lock_irq(&n->list_lock); |
|
free_block(cachep, ac->entry, ac->avail, node, &list); |
|
spin_unlock_irq(&n->list_lock); |
|
slabs_destroy(cachep, &list); |
|
} |
|
free_percpu(prev); |
|
|
|
setup_node: |
|
return setup_kmem_cache_nodes(cachep, gfp); |
|
} |
|
|
|
/* Called with slab_mutex held always */ |
|
static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) |
|
{ |
|
int err; |
|
int limit = 0; |
|
int shared = 0; |
|
int batchcount = 0; |
|
|
|
err = cache_random_seq_create(cachep, cachep->num, gfp); |
|
if (err) |
|
goto end; |
|
|
|
/* |
|
* The head array serves three purposes: |
|
* - create a LIFO ordering, i.e. return objects that are cache-warm |
|
* - reduce the number of spinlock operations. |
|
* - reduce the number of linked list operations on the slab and |
|
* bufctl chains: array operations are cheaper. |
|
* The numbers are guessed, we should auto-tune as described by |
|
* Bonwick. |
|
*/ |
|
if (cachep->size > 131072) |
|
limit = 1; |
|
else if (cachep->size > PAGE_SIZE) |
|
limit = 8; |
|
else if (cachep->size > 1024) |
|
limit = 24; |
|
else if (cachep->size > 256) |
|
limit = 54; |
|
else |
|
limit = 120; |
|
|
|
/* |
|
* CPU bound tasks (e.g. network routing) can exhibit cpu bound |
|
* allocation behaviour: Most allocs on one cpu, most free operations |
|
* on another cpu. For these cases, an efficient object passing between |
|
* cpus is necessary. This is provided by a shared array. The array |
|
* replaces Bonwick's magazine layer. |
|
* On uniprocessor, it's functionally equivalent (but less efficient) |
|
* to a larger limit. Thus disabled by default. |
|
*/ |
|
shared = 0; |
|
if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1) |
|
shared = 8; |
|
|
|
#if DEBUG |
|
/* |
|
* With debugging enabled, large batchcount lead to excessively long |
|
* periods with disabled local interrupts. Limit the batchcount |
|
*/ |
|
if (limit > 32) |
|
limit = 32; |
|
#endif |
|
batchcount = (limit + 1) / 2; |
|
err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp); |
|
end: |
|
if (err) |
|
pr_err("enable_cpucache failed for %s, error %d\n", |
|
cachep->name, -err); |
|
return err; |
|
} |
|
|
|
/* |
|
* Drain an array if it contains any elements taking the node lock only if |
|
* necessary. Note that the node listlock also protects the array_cache |
|
* if drain_array() is used on the shared array. |
|
*/ |
|
static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, |
|
struct array_cache *ac, int node) |
|
{ |
|
LIST_HEAD(list); |
|
|
|
/* ac from n->shared can be freed if we don't hold the slab_mutex. */ |
|
check_mutex_acquired(); |
|
|
|
if (!ac || !ac->avail) |
|
return; |
|
|
|
if (ac->touched) { |
|
ac->touched = 0; |
|
return; |
|
} |
|
|
|
spin_lock_irq(&n->list_lock); |
|
drain_array_locked(cachep, ac, node, false, &list); |
|
spin_unlock_irq(&n->list_lock); |
|
|
|
slabs_destroy(cachep, &list); |
|
} |
|
|
|
/** |
|
* cache_reap - Reclaim memory from caches. |
|
* @w: work descriptor |
|
* |
|
* Called from workqueue/eventd every few seconds. |
|
* Purpose: |
|
* - clear the per-cpu caches for this CPU. |
|
* - return freeable pages to the main free memory pool. |
|
* |
|
* If we cannot acquire the cache chain mutex then just give up - we'll try |
|
* again on the next iteration. |
|
*/ |
|
static void cache_reap(struct work_struct *w) |
|
{ |
|
struct kmem_cache *searchp; |
|
struct kmem_cache_node *n; |
|
int node = numa_mem_id(); |
|
struct delayed_work *work = to_delayed_work(w); |
|
|
|
if (!mutex_trylock(&slab_mutex)) |
|
/* Give up. Setup the next iteration. */ |
|
goto out; |
|
|
|
list_for_each_entry(searchp, &slab_caches, list) { |
|
check_irq_on(); |
|
|
|
/* |
|
* We only take the node lock if absolutely necessary and we |
|
* have established with reasonable certainty that |
|
* we can do some work if the lock was obtained. |
|
*/ |
|
n = get_node(searchp, node); |
|
|
|
reap_alien(searchp, n); |
|
|
|
drain_array(searchp, n, cpu_cache_get(searchp), node); |
|
|
|
/* |
|
* These are racy checks but it does not matter |
|
* if we skip one check or scan twice. |
|
*/ |
|
if (time_after(n->next_reap, jiffies)) |
|
goto next; |
|
|
|
n->next_reap = jiffies + REAPTIMEOUT_NODE; |
|
|
|
drain_array(searchp, n, n->shared, node); |
|
|
|
if (n->free_touched) |
|
n->free_touched = 0; |
|
else { |
|
int freed; |
|
|
|
freed = drain_freelist(searchp, n, (n->free_limit + |
|
5 * searchp->num - 1) / (5 * searchp->num)); |
|
STATS_ADD_REAPED(searchp, freed); |
|
} |
|
next: |
|
cond_resched(); |
|
} |
|
check_irq_on(); |
|
mutex_unlock(&slab_mutex); |
|
next_reap_node(); |
|
out: |
|
/* Set up the next iteration */ |
|
schedule_delayed_work_on(smp_processor_id(), work, |
|
round_jiffies_relative(REAPTIMEOUT_AC)); |
|
} |
|
|
|
void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) |
|
{ |
|
unsigned long active_objs, num_objs, active_slabs; |
|
unsigned long total_slabs = 0, free_objs = 0, shared_avail = 0; |
|
unsigned long free_slabs = 0; |
|
int node; |
|
struct kmem_cache_node *n; |
|
|
|
for_each_kmem_cache_node(cachep, node, n) { |
|
check_irq_on(); |
|
spin_lock_irq(&n->list_lock); |
|
|
|
total_slabs += n->total_slabs; |
|
free_slabs += n->free_slabs; |
|
free_objs += n->free_objects; |
|
|
|
if (n->shared) |
|
shared_avail += n->shared->avail; |
|
|
|
spin_unlock_irq(&n->list_lock); |
|
} |
|
num_objs = total_slabs * cachep->num; |
|
active_slabs = total_slabs - free_slabs; |
|
active_objs = num_objs - free_objs; |
|
|
|
sinfo->active_objs = active_objs; |
|
sinfo->num_objs = num_objs; |
|
sinfo->active_slabs = active_slabs; |
|
sinfo->num_slabs = total_slabs; |
|
sinfo->shared_avail = shared_avail; |
|
sinfo->limit = cachep->limit; |
|
sinfo->batchcount = cachep->batchcount; |
|
sinfo->shared = cachep->shared; |
|
sinfo->objects_per_slab = cachep->num; |
|
sinfo->cache_order = cachep->gfporder; |
|
} |
|
|
|
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep) |
|
{ |
|
#if STATS |
|
{ /* node stats */ |
|
unsigned long high = cachep->high_mark; |
|
unsigned long allocs = cachep->num_allocations; |
|
unsigned long grown = cachep->grown; |
|
unsigned long reaped = cachep->reaped; |
|
unsigned long errors = cachep->errors; |
|
unsigned long max_freeable = cachep->max_freeable; |
|
unsigned long node_allocs = cachep->node_allocs; |
|
unsigned long node_frees = cachep->node_frees; |
|
unsigned long overflows = cachep->node_overflow; |
|
|
|
seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu", |
|
allocs, high, grown, |
|
reaped, errors, max_freeable, node_allocs, |
|
node_frees, overflows); |
|
} |
|
/* cpu stats */ |
|
{ |
|
unsigned long allochit = atomic_read(&cachep->allochit); |
|
unsigned long allocmiss = atomic_read(&cachep->allocmiss); |
|
unsigned long freehit = atomic_read(&cachep->freehit); |
|
unsigned long freemiss = atomic_read(&cachep->freemiss); |
|
|
|
seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", |
|
allochit, allocmiss, freehit, freemiss); |
|
} |
|
#endif |
|
} |
|
|
|
#define MAX_SLABINFO_WRITE 128 |
|
/** |
|
* slabinfo_write - Tuning for the slab allocator |
|
* @file: unused |
|
* @buffer: user buffer |
|
* @count: data length |
|
* @ppos: unused |
|
* |
|
* Return: %0 on success, negative error code otherwise. |
|
*/ |
|
ssize_t slabinfo_write(struct file *file, const char __user *buffer, |
|
size_t count, loff_t *ppos) |
|
{ |
|
char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; |
|
int limit, batchcount, shared, res; |
|
struct kmem_cache *cachep; |
|
|
|
if (count > MAX_SLABINFO_WRITE) |
|
return -EINVAL; |
|
if (copy_from_user(&kbuf, buffer, count)) |
|
return -EFAULT; |
|
kbuf[MAX_SLABINFO_WRITE] = '\0'; |
|
|
|
tmp = strchr(kbuf, ' '); |
|
if (!tmp) |
|
return -EINVAL; |
|
*tmp = '\0'; |
|
tmp++; |
|
if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) |
|
return -EINVAL; |
|
|
|
/* Find the cache in the chain of caches. */ |
|
mutex_lock(&slab_mutex); |
|
res = -EINVAL; |
|
list_for_each_entry(cachep, &slab_caches, list) { |
|
if (!strcmp(cachep->name, kbuf)) { |
|
if (limit < 1 || batchcount < 1 || |
|
batchcount > limit || shared < 0) { |
|
res = 0; |
|
} else { |
|
res = do_tune_cpucache(cachep, limit, |
|
batchcount, shared, |
|
GFP_KERNEL); |
|
} |
|
break; |
|
} |
|
} |
|
mutex_unlock(&slab_mutex); |
|
if (res >= 0) |
|
res = count; |
|
return res; |
|
} |
|
|
|
#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, |
|
const struct slab *slab, bool to_user) |
|
{ |
|
struct kmem_cache *cachep; |
|
unsigned int objnr; |
|
unsigned long offset; |
|
|
|
ptr = kasan_reset_tag(ptr); |
|
|
|
/* Find and validate object. */ |
|
cachep = slab->slab_cache; |
|
objnr = obj_to_index(cachep, slab, (void *)ptr); |
|
BUG_ON(objnr >= cachep->num); |
|
|
|
/* Find offset within object. */ |
|
if (is_kfence_address(ptr)) |
|
offset = ptr - kfence_object_start(ptr); |
|
else |
|
offset = ptr - index_to_obj(cachep, slab, objnr) - obj_offset(cachep); |
|
|
|
/* Allow address range falling entirely within usercopy region. */ |
|
if (offset >= cachep->useroffset && |
|
offset - cachep->useroffset <= cachep->usersize && |
|
n <= cachep->useroffset - offset + cachep->usersize) |
|
return; |
|
|
|
usercopy_abort("SLAB object", cachep->name, to_user, offset, n); |
|
} |
|
#endif /* CONFIG_HARDENED_USERCOPY */
|
|
|