linux-imx

// SPDX-License-Identifier: GPL-2.0

#include <linux/init.h>

#include <linux/memblock.h>

#include <linux/fs.h>

#include <linux/sysfs.h>

#include <linux/kobject.h>

#include <linux/mm.h>

#include <linux/mmzone.h>

#include <linux/pagemap.h>

#include <linux/rmap.h>

#include <linux/mmu_notifier.h>

#include <linux/page_ext.h>

#include <linux/page_idle.h>

​

#define BITMAP_CHUNK_SIZE   sizeof(u64)

#define BITMAP_CHUNK_BITS   (BITMAP_CHUNK_SIZE * BITS_PER_BYTE)

​

/*

 * Idle page tracking only considers user memory pages, for other types of

 * pages the idle flag is always unset and an attempt to set it is silently

 * ignored.

 *

 * We treat a page as a user memory page if it is on an LRU list, because it is

 * always safe to pass such a page to rmap_walk(), which is essential for idle

 * page tracking. With such an indicator of user pages we can skip isolated

 * pages, but since there are not usually many of them, it will hardly affect

 * the overall result.

 *

 * This function tries to get a user memory page by pfn as described above.

 */

static struct page *page_idle_get_page(unsigned long pfn)

{

    struct page *page;

    pg_data_t *pgdat;

​

    if (!pfn_valid(pfn))

        return NULL;

​

    page = pfn_to_page(pfn);

    if (!page || !PageLRU(page) ||

        !get_page_unless_zero(page))

        return NULL;

​

    pgdat = page_pgdat(page);

    spin_lock_irq(&pgdat->lru_lock);

    if (unlikely(!PageLRU(page))) {

        put_page(page);

        page = NULL;

    }

    spin_unlock_irq(&pgdat->lru_lock);

    return page;

}

​

static bool page_idle_clear_pte_refs_one(struct page *page,

                    struct vm_area_struct *vma,

                    unsigned long addr, void *arg)

{

    struct page_vma_mapped_walk pvmw = {

        .page = page,

        .vma = vma,

        .address = addr,

    };

    bool referenced = false;