1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_PAGE_COUNTER_H 3 #define _LINUX_PAGE_COUNTER_H 4 5 #include <linux/atomic.h> 6 #include <linux/kernel.h> 7 #include <asm/page.h> 8 9 struct page_counter { 10 atomic_long_t count; 11 unsigned long limit; 12 struct page_counter *parent; 13 14 /* legacy */ 15 unsigned long watermark; 16 unsigned long failcnt; 17 }; 18 19 #if BITS_PER_LONG == 32 20 #define PAGE_COUNTER_MAX LONG_MAX 21 #else 22 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE) 23 #endif 24 25 static inline void page_counter_init(struct page_counter *counter, 26 struct page_counter *parent) 27 { 28 atomic_long_set(&counter->count, 0); 29 counter->limit = PAGE_COUNTER_MAX; 30 counter->parent = parent; 31 } 32 33 static inline unsigned long page_counter_read(struct page_counter *counter) 34 { 35 return atomic_long_read(&counter->count); 36 } 37 38 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); 39 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); 40 bool page_counter_try_charge(struct page_counter *counter, 41 unsigned long nr_pages, 42 struct page_counter **fail); 43 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); 44 int page_counter_limit(struct page_counter *counter, unsigned long limit); 45 int page_counter_memparse(const char *buf, const char *max, 46 unsigned long *nr_pages); 47 48 static inline void page_counter_reset_watermark(struct page_counter *counter) 49 { 50 counter->watermark = page_counter_read(counter); 51 } 52 53 #endif /* _LINUX_PAGE_COUNTER_H */ 54