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/cache.h> 7 #include <linux/kernel.h> 8 #include <asm/page.h> 9 10 struct page_counter { 11 /* 12 * Make sure 'usage' does not share cacheline with any other field. The 13 * memcg->memory.usage is a hot member of struct mem_cgroup. 14 */ 15 atomic_long_t usage; 16 CACHELINE_PADDING(_pad1_); 17 18 /* effective memory.min and memory.min usage tracking */ 19 unsigned long emin; 20 atomic_long_t min_usage; 21 atomic_long_t children_min_usage; 22 23 /* effective memory.low and memory.low usage tracking */ 24 unsigned long elow; 25 atomic_long_t low_usage; 26 atomic_long_t children_low_usage; 27 28 unsigned long watermark; 29 unsigned long failcnt; 30 31 /* Keep all the read most fields in a separete cacheline. */ 32 CACHELINE_PADDING(_pad2_); 33 34 unsigned long min; 35 unsigned long low; 36 unsigned long high; 37 unsigned long max; 38 struct page_counter *parent; 39 } ____cacheline_internodealigned_in_smp; 40 41 #if BITS_PER_LONG == 32 42 #define PAGE_COUNTER_MAX LONG_MAX 43 #else 44 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE) 45 #endif 46 47 static inline void page_counter_init(struct page_counter *counter, 48 struct page_counter *parent) 49 { 50 atomic_long_set(&counter->usage, 0); 51 counter->max = PAGE_COUNTER_MAX; 52 counter->parent = parent; 53 } 54 55 static inline unsigned long page_counter_read(struct page_counter *counter) 56 { 57 return atomic_long_read(&counter->usage); 58 } 59 60 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); 61 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); 62 bool page_counter_try_charge(struct page_counter *counter, 63 unsigned long nr_pages, 64 struct page_counter **fail); 65 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); 66 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages); 67 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages); 68 69 static inline void page_counter_set_high(struct page_counter *counter, 70 unsigned long nr_pages) 71 { 72 WRITE_ONCE(counter->high, nr_pages); 73 } 74 75 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages); 76 int page_counter_memparse(const char *buf, const char *max, 77 unsigned long *nr_pages); 78 79 static inline void page_counter_reset_watermark(struct page_counter *counter) 80 { 81 counter->watermark = page_counter_read(counter); 82 } 83 84 #endif /* _LINUX_PAGE_COUNTER_H */ 85