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 high; 14 unsigned long max; 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 * 'parent' is placed here to be far from 'usage' to reduce 32 * cache false sharing, as 'usage' is written mostly while 33 * parent is frequently read for cgroup's hierarchical 34 * counting nature. 35 */ 36 struct page_counter *parent; 37 }; 38 39 #if BITS_PER_LONG == 32 40 #define PAGE_COUNTER_MAX LONG_MAX 41 #else 42 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE) 43 #endif 44 45 static inline void page_counter_init(struct page_counter *counter, 46 struct page_counter *parent) 47 { 48 atomic_long_set(&counter->usage, 0); 49 counter->max = PAGE_COUNTER_MAX; 50 counter->parent = parent; 51 } 52 53 static inline unsigned long page_counter_read(struct page_counter *counter) 54 { 55 return atomic_long_read(&counter->usage); 56 } 57 58 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); 59 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); 60 bool page_counter_try_charge(struct page_counter *counter, 61 unsigned long nr_pages, 62 struct page_counter **fail); 63 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); 64 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages); 65 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages); 66 67 static inline void page_counter_set_high(struct page_counter *counter, 68 unsigned long nr_pages) 69 { 70 WRITE_ONCE(counter->high, nr_pages); 71 } 72 73 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages); 74 int page_counter_memparse(const char *buf, const char *max, 75 unsigned long *nr_pages); 76 77 static inline void page_counter_reset_watermark(struct page_counter *counter) 78 { 79 counter->watermark = page_counter_read(counter); 80 } 81 82 #endif /* _LINUX_PAGE_COUNTER_H */ 83