LXR linux/include/linux/page

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