linux/include/linux/page_counter.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PAGE_COUNTER_H
#define _LINUX_PAGE_COUNTER_H

#include <linux/atomic.h>
#include <linux/cache.h>
#include <linux/limits.h>
#include <asm/page.h>

struct page_counter { … } ____cacheline_internodealigned_in_smp;

#if BITS_PER_LONG == 32
#define PAGE_COUNTER_MAX …
#else
#define PAGE_COUNTER_MAX …
#endif

/*
 * Protection is supported only for the first counter (with id 0).
 */
static inline void page_counter_init(struct page_counter *counter,
				     struct page_counter *parent,
				     bool protection_support)
{ … }

static inline unsigned long page_counter_read(struct page_counter *counter)
{ … }

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)
{ … }

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)
{ … }

#ifdef CONFIG_MEMCG
void page_counter_calculate_protection(struct page_counter *root,
				       struct page_counter *counter,
				       bool recursive_protection);
#else
static inline void page_counter_calculate_protection(struct page_counter *root,
						     struct page_counter *counter,
						     bool recursive_protection) {}
#endif

#endif /* _LINUX_PAGE_COUNTER_H */