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 struct page_counter *parent; 16 17 /* effective memory.min and memory.min usage tracking */ 18 unsigned long emin; 19 atomic_long_t min_usage; 20 atomic_long_t children_min_usage; 21 22 /* effective memory.low and memory.low usage tracking */ 23 unsigned long elow; 24 atomic_long_t low_usage; 25 atomic_long_t children_low_usage; 26 27 /* legacy */ 28 unsigned long watermark; 29 unsigned long failcnt; 30 }; 31 32 #if BITS_PER_LONG == 32 33 #define PAGE_COUNTER_MAX LONG_MAX 34 #else 35 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE) 36 #endif 37 38 static inline void page_counter_init(struct page_counter *counter, 39 struct page_counter *parent) 40 { 41 atomic_long_set(&counter->usage, 0); 42 counter->max = PAGE_COUNTER_MAX; 43 counter->parent = parent; 44 } 45 46 static inline unsigned long page_counter_read(struct page_counter *counter) 47 { 48 return atomic_long_read(&counter->usage); 49 } 50 51 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); 52 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); 53 bool page_counter_try_charge(struct page_counter *counter, 54 unsigned long nr_pages, 55 struct page_counter **fail); 56 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); 57 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages); 58 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages); 59 60 static inline void page_counter_set_high(struct page_counter *counter, 61 unsigned long nr_pages) 62 { 63 WRITE_ONCE(counter->high, nr_pages); 64 } 65 66 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages); 67 int page_counter_memparse(const char *buf, const char *max, 68 unsigned long *nr_pages); 69 70 static inline void page_counter_reset_watermark(struct page_counter *counter) 71 { 72 counter->watermark = page_counter_read(counter); 73 } 74 75 #endif /* _LINUX_PAGE_COUNTER_H */ 76