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 usage; 11 unsigned long min; 12 unsigned long low; 13 unsigned long max; 14 struct page_counter *parent; 15 16 /* effective memory.min and memory.min usage tracking */ 17 unsigned long emin; 18 atomic_long_t min_usage; 19 atomic_long_t children_min_usage; 20 21 /* effective memory.low and memory.low usage tracking */ 22 unsigned long elow; 23 atomic_long_t low_usage; 24 atomic_long_t children_low_usage; 25 26 /* legacy */ 27 unsigned long watermark; 28 unsigned long failcnt; 29 }; 30 31 #if BITS_PER_LONG == 32 32 #define PAGE_COUNTER_MAX LONG_MAX 33 #else 34 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE) 35 #endif 36 37 static inline void page_counter_init(struct page_counter *counter, 38 struct page_counter *parent) 39 { 40 atomic_long_set(&counter->usage, 0); 41 counter->max = PAGE_COUNTER_MAX; 42 counter->parent = parent; 43 } 44 45 static inline unsigned long page_counter_read(struct page_counter *counter) 46 { 47 return atomic_long_read(&counter->usage); 48 } 49 50 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); 51 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); 52 bool page_counter_try_charge(struct page_counter *counter, 53 unsigned long nr_pages, 54 struct page_counter **fail); 55 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); 56 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages); 57 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages); 58 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages); 59 int page_counter_memparse(const char *buf, const char *max, 60 unsigned long *nr_pages); 61 62 static inline void page_counter_reset_watermark(struct page_counter *counter) 63 { 64 counter->watermark = page_counter_read(counter); 65 } 66 67 #endif /* _LINUX_PAGE_COUNTER_H */ 68