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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PAGE_COUNTER_H
#define _LINUX_PAGE_COUNTER_H
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <asm/page.h>
struct page_counter {
atomic_long_t usage;
unsigned long min;
unsigned long low;
unsigned long high;
unsigned long max;
/* effective memory.min and memory.min usage tracking */
unsigned long emin;
atomic_long_t min_usage;
atomic_long_t children_min_usage;
/* effective memory.low and memory.low usage tracking */
unsigned long elow;
atomic_long_t low_usage;
atomic_long_t children_low_usage;
/* legacy */
unsigned long watermark;
unsigned long failcnt;
/*
* 'parent' is placed here to be far from 'usage' to reduce
* cache false sharing, as 'usage' is written mostly while
* parent is frequently read for cgroup's hierarchical
* counting nature.
*/
struct page_counter *parent;
};
#if BITS_PER_LONG == 32
#define PAGE_COUNTER_MAX LONG_MAX
#else
#define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
#endif
static inline void page_counter_init(struct page_counter *counter,
struct page_counter *parent)
{
atomic_long_set(&counter->usage, 0);
counter->max = PAGE_COUNTER_MAX;
counter->parent = parent;
}
static inline unsigned long page_counter_read(struct page_counter *counter)
{
return atomic_long_read(&counter->usage);
}
void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
bool page_counter_try_charge(struct page_counter *counter,
unsigned long nr_pages,
struct page_counter **fail);
void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages);
void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
static inline void page_counter_set_high(struct page_counter *counter,
unsigned long nr_pages)
{
WRITE_ONCE(counter->high, nr_pages);
}
int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
int page_counter_memparse(const char *buf, const char *max,
unsigned long *nr_pages);
static inline void page_counter_reset_watermark(struct page_counter *counter)
{
counter->watermark = page_counter_read(counter);
}
#endif /* _LINUX_PAGE_COUNTER_H */
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