mm/fail_page_alloc.c

root/mm/fail_page_alloc.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/fault-inject.h>
#include <linux/debugfs.h>
#include <linux/error-injection.h>
#include <linux/mm.h>

static struct {
        struct fault_attr attr;

        bool ignore_gfp_highmem;
        bool ignore_gfp_reclaim;
        u32 min_order;
} fail_page_alloc = {
        .attr = FAULT_ATTR_INITIALIZER,
        .ignore_gfp_reclaim = true,
        .ignore_gfp_highmem = true,
        .min_order = 1,
};

static int __init setup_fail_page_alloc(char *str)
{
        return setup_fault_attr(&fail_page_alloc.attr, str);
}
__setup("fail_page_alloc=", setup_fail_page_alloc);

bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
        int flags = 0;

        if (order < fail_page_alloc.min_order)
                return false;
        if (gfp_mask & __GFP_NOFAIL)
                return false;
        if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
                return false;
        if (fail_page_alloc.ignore_gfp_reclaim &&
                        (gfp_mask & __GFP_DIRECT_RECLAIM))
                return false;

        /* See comment in __should_failslab() */
        if (gfp_mask & __GFP_NOWARN)
                flags |= FAULT_NOWARN;

        return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
}
ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

static int __init fail_page_alloc_debugfs(void)
{
        umode_t mode = S_IFREG | 0600;
        struct dentry *dir;

        dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
                                        &fail_page_alloc.attr);

        debugfs_create_bool("ignore-gfp-wait", mode, dir,
                            &fail_page_alloc.ignore_gfp_reclaim);
        debugfs_create_bool("ignore-gfp-highmem", mode, dir,
                            &fail_page_alloc.ignore_gfp_highmem);
        debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);

        return 0;
}

late_initcall(fail_page_alloc_debugfs);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
Linux
