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