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192 lines
4.9 KiB
192 lines
4.9 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _LINUX_PAGE_REF_H |
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#define _LINUX_PAGE_REF_H |
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#include <linux/atomic.h> |
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#include <linux/mm_types.h> |
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#include <linux/page-flags.h> |
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#include <linux/tracepoint-defs.h> |
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DECLARE_TRACEPOINT(page_ref_set); |
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DECLARE_TRACEPOINT(page_ref_mod); |
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DECLARE_TRACEPOINT(page_ref_mod_and_test); |
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DECLARE_TRACEPOINT(page_ref_mod_and_return); |
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DECLARE_TRACEPOINT(page_ref_mod_unless); |
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DECLARE_TRACEPOINT(page_ref_freeze); |
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DECLARE_TRACEPOINT(page_ref_unfreeze); |
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#ifdef CONFIG_DEBUG_PAGE_REF |
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/* |
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* Ideally we would want to use the trace_<tracepoint>_enabled() helper |
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* functions. But due to include header file issues, that is not |
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* feasible. Instead we have to open code the static key functions. |
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* |
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* See trace_##name##_enabled(void) in include/linux/tracepoint.h |
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*/ |
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#define page_ref_tracepoint_active(t) tracepoint_enabled(t) |
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extern void __page_ref_set(struct page *page, int v); |
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extern void __page_ref_mod(struct page *page, int v); |
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extern void __page_ref_mod_and_test(struct page *page, int v, int ret); |
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extern void __page_ref_mod_and_return(struct page *page, int v, int ret); |
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extern void __page_ref_mod_unless(struct page *page, int v, int u); |
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extern void __page_ref_freeze(struct page *page, int v, int ret); |
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extern void __page_ref_unfreeze(struct page *page, int v); |
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#else |
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#define page_ref_tracepoint_active(t) false |
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static inline void __page_ref_set(struct page *page, int v) |
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{ |
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} |
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static inline void __page_ref_mod(struct page *page, int v) |
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{ |
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} |
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static inline void __page_ref_mod_and_test(struct page *page, int v, int ret) |
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{ |
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} |
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static inline void __page_ref_mod_and_return(struct page *page, int v, int ret) |
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{ |
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} |
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static inline void __page_ref_mod_unless(struct page *page, int v, int u) |
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{ |
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} |
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static inline void __page_ref_freeze(struct page *page, int v, int ret) |
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{ |
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} |
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static inline void __page_ref_unfreeze(struct page *page, int v) |
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{ |
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} |
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#endif |
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static inline int page_ref_count(struct page *page) |
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{ |
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return atomic_read(&page->_refcount); |
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} |
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static inline int page_count(struct page *page) |
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{ |
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return atomic_read(&compound_head(page)->_refcount); |
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} |
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static inline void set_page_count(struct page *page, int v) |
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{ |
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atomic_set(&page->_refcount, v); |
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if (page_ref_tracepoint_active(page_ref_set)) |
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__page_ref_set(page, v); |
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} |
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/* |
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* Setup the page count before being freed into the page allocator for |
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* the first time (boot or memory hotplug) |
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*/ |
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static inline void init_page_count(struct page *page) |
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{ |
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set_page_count(page, 1); |
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} |
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static inline void page_ref_add(struct page *page, int nr) |
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{ |
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atomic_add(nr, &page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod)) |
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__page_ref_mod(page, nr); |
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} |
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static inline void page_ref_sub(struct page *page, int nr) |
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{ |
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atomic_sub(nr, &page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod)) |
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__page_ref_mod(page, -nr); |
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} |
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static inline int page_ref_sub_return(struct page *page, int nr) |
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{ |
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int ret = atomic_sub_return(nr, &page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod_and_return)) |
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__page_ref_mod_and_return(page, -nr, ret); |
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return ret; |
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} |
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static inline void page_ref_inc(struct page *page) |
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{ |
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atomic_inc(&page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod)) |
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__page_ref_mod(page, 1); |
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} |
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static inline void page_ref_dec(struct page *page) |
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{ |
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atomic_dec(&page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod)) |
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__page_ref_mod(page, -1); |
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} |
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static inline int page_ref_sub_and_test(struct page *page, int nr) |
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{ |
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int ret = atomic_sub_and_test(nr, &page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod_and_test)) |
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__page_ref_mod_and_test(page, -nr, ret); |
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return ret; |
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} |
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static inline int page_ref_inc_return(struct page *page) |
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{ |
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int ret = atomic_inc_return(&page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod_and_return)) |
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__page_ref_mod_and_return(page, 1, ret); |
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return ret; |
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} |
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static inline int page_ref_dec_and_test(struct page *page) |
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{ |
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int ret = atomic_dec_and_test(&page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod_and_test)) |
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__page_ref_mod_and_test(page, -1, ret); |
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return ret; |
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} |
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static inline int page_ref_dec_return(struct page *page) |
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{ |
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int ret = atomic_dec_return(&page->_refcount); |
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if (page_ref_tracepoint_active(page_ref_mod_and_return)) |
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__page_ref_mod_and_return(page, -1, ret); |
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return ret; |
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} |
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static inline int page_ref_add_unless(struct page *page, int nr, int u) |
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{ |
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int ret = atomic_add_unless(&page->_refcount, nr, u); |
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if (page_ref_tracepoint_active(page_ref_mod_unless)) |
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__page_ref_mod_unless(page, nr, ret); |
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return ret; |
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} |
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static inline int page_ref_freeze(struct page *page, int count) |
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{ |
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int ret = likely(atomic_cmpxchg(&page->_refcount, count, 0) == count); |
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if (page_ref_tracepoint_active(page_ref_freeze)) |
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__page_ref_freeze(page, count, ret); |
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return ret; |
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} |
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static inline void page_ref_unfreeze(struct page *page, int count) |
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{ |
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VM_BUG_ON_PAGE(page_count(page) != 0, page); |
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VM_BUG_ON(count == 0); |
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atomic_set_release(&page->_refcount, count); |
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if (page_ref_tracepoint_active(page_ref_unfreeze)) |
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__page_ref_unfreeze(page, count); |
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} |
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#endif
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