Commit 933e312e authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
Browse files

[PATCH] fault-injection capability for alloc_pages()



This patch provides fault-injection capability for alloc_pages()

Boot option:

fail_page_alloc=<interval>,<probability>,<space>,<times>

	<interval> -- specifies the interval of failures.

	<probability> -- specifies how often it should fail in percent.

	<space> -- specifies the size of free space where memory can be
		   allocated safely in pages.

	<times> -- specifies how many times failures may happen at most.

Debugfs:

/debug/fail_page_alloc/interval
/debug/fail_page_alloc/probability
/debug/fail_page_alloc/specifies
/debug/fail_page_alloc/times
/debug/fail_page_alloc/ignore-gfp-highmem
/debug/fail_page_alloc/ignore-gfp-wait

Example:

	fail_page_alloc=10,100,0,-1

The page allocation (alloc_pages(), ...) fails once per 10 times.
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8a8b6502
......@@ -424,6 +424,13 @@ config FAILSLAB
help
This option provides fault-injection capabilitiy for kmalloc.
config FAIL_PAGE_ALLOC
bool "Fault-injection capabilitiy for alloc_pages()"
depends on DEBUG_KERNEL
select FAULT_INJECTION
help
This option provides fault-injection capabilitiy for alloc_pages().
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS
......
......@@ -40,6 +40,7 @@
#include <linux/sort.h>
#include <linux/pfn.h>
#include <linux/backing-dev.h>
#include <linux/fault-inject.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
......@@ -892,6 +893,89 @@ failed:
#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
#ifdef CONFIG_FAIL_PAGE_ALLOC
static struct fail_page_alloc_attr {
struct fault_attr attr;
u32 ignore_gfp_highmem;
u32 ignore_gfp_wait;
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
struct dentry *ignore_gfp_highmem_file;
struct dentry *ignore_gfp_wait_file;
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
} fail_page_alloc = {
.attr = FAULT_ATTR_INITIALIZER,
};
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);
static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
if (gfp_mask & __GFP_NOFAIL)
return 0;
if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
return 0;
if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
return 0;
return should_fail(&fail_page_alloc.attr, 1 << order);
}
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init fail_page_alloc_debugfs(void)
{
mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
struct dentry *dir;
int err;
err = init_fault_attr_dentries(&fail_page_alloc.attr,
"fail_page_alloc");
if (err)
return err;
dir = fail_page_alloc.attr.dentries.dir;
fail_page_alloc.ignore_gfp_wait_file =
debugfs_create_bool("ignore-gfp-wait", mode, dir,
&fail_page_alloc.ignore_gfp_wait);
fail_page_alloc.ignore_gfp_highmem_file =
debugfs_create_bool("ignore-gfp-highmem", mode, dir,
&fail_page_alloc.ignore_gfp_highmem);
if (!fail_page_alloc.ignore_gfp_wait_file ||
!fail_page_alloc.ignore_gfp_highmem_file) {
err = -ENOMEM;
debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
cleanup_fault_attr_dentries(&fail_page_alloc.attr);
}
return err;
}
late_initcall(fail_page_alloc_debugfs);
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
#else /* CONFIG_FAIL_PAGE_ALLOC */
static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
return 0;
}
#endif /* CONFIG_FAIL_PAGE_ALLOC */
/*
* Return 1 if free pages are above 'mark'. This takes into account the order
* of the allocation.
......@@ -1136,6 +1220,9 @@ __alloc_pages(gfp_t gfp_mask, unsigned int order,
might_sleep_if(wait);
if (should_fail_alloc_page(gfp_mask, order))
return NULL;
restart:
z = zonelist->zones; /* the list of zones suitable for gfp_mask */
......
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