linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Quicklist support.

 *

 * Quicklists are light weight lists of pages that have a defined state

 * on alloc and free. Pages must be in the quicklist specific defined state

 * (zero by default) when the page is freed. It seems that the initial idea

 * for such lists first came from Dave Miller and then various other people

 * improved on it.

 *

 * Copyright (C) 2007 SGI,

 *  Christoph Lameter <cl@linux.com>

 *      Generalized, added support for multiple lists and

 *      constructors / destructors.

 */

#include <linux/kernel.h>

​

#include <linux/gfp.h>

#include <linux/mm.h>

#include <linux/mmzone.h>

#include <linux/quicklist.h>

​

DEFINE_PER_CPU(struct quicklist [CONFIG_NR_QUICK], quicklist);

​

#define FRACTION_OF_NODE_MEM    16

​

static unsigned long max_pages(unsigned long min_pages)

{

    unsigned long node_free_pages, max;

    int node = numa_node_id();

    struct zone *zones = NODE_DATA(node)->node_zones;

    int num_cpus_on_node;

​

    node_free_pages =

#ifdef CONFIG_ZONE_DMA

        zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) +

#endif

#ifdef CONFIG_ZONE_DMA32

        zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) +

#endif

        zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);

​

    max = node_free_pages / FRACTION_OF_NODE_MEM;

​

    num_cpus_on_node = cpumask_weight(cpumask_of_node(node));

    max /= num_cpus_on_node;

​

    return max(max, min_pages);

}

​

static long min_pages_to_free(struct quicklist *q,

    unsigned long min_pages, long max_free)

{

    long pages_to_free;

​

    pages_to_free = q->nr_pages - max_pages(min_pages);

​

    return min(pages_to_free, max_free);

}

​

/*

 * Trim down the number of pages in the quicklist

 */