[patch 3/5] fail-injection capability for alloc_pages()

Akinobu Mita
2006-08-23T11:34:59Z

[-- Attachment #1: fail_alloc_pages.patch --]
[-- Type: text/plain, Size: 2881 bytes --]

This patch provides fail-injection capability for alloc_pages()

boot option:

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

<probability>

specifies how often it should fail in percent.

<interval>

specifies the interval of failures.

<times>

specifies how many times failures may happen at most.

<space>

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

Example:

fail_page_alloc=100,10,-1,0

page allocation fails once per 10 times.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>

include/linux/should_fail.h | 4 ++++
lib/Kconfig.debug | 7 +++++++
mm/page_alloc.c | 20 ++++++++++++++++++++
3 files changed, 31 insertions(+)

Index: work-failmalloc/lib/Kconfig.debug
===================================================================
--- work-failmalloc.orig/lib/Kconfig.debug
+++ work-failmalloc/lib/Kconfig.debug
@@ -379,3 +379,10 @@ 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 SHOULD_FAIL
+ help
+ This option provides fault-injection capabilitiy for alloc_pages().
+
Index: work-failmalloc/mm/page_alloc.c
===================================================================
--- work-failmalloc.orig/mm/page_alloc.c
+++ work-failmalloc/mm/page_alloc.c
@@ -37,6 +37,7 @@
#include <linux/vmalloc.h>
#include <linux/mempolicy.h>
#include <linux/stop_machine.h>
+#include <linux/should_fail.h>

#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -903,6 +904,21 @@ get_page_from_freelist(gfp_t gfp_mask, u
return page;
}

+#ifdef CONFIG_FAIL_PAGE_ALLOC
+
+static DEFINE_SHOULD_FAIL(fail_page_alloc_data);
+
+static int __init setup_fail_page_alloc(char *str)
+{
+ return setup_should_fail(&fail_page_alloc_data, str);
+}
+__setup("fail_page_alloc=", setup_fail_page_alloc);
+
+struct should_fail_data *fail_page_alloc = &fail_page_alloc_data;
+EXPORT_SYMBOL_GPL(fail_page_alloc);
+
+#endif
+
/*
* This is the 'heart' of the zoned buddy allocator.
*/
@@ -921,6 +937,10 @@ __alloc_pages(gfp_t gfp_mask, unsigned i

might_sleep_if(wait);

+ if (!(gfp_mask & __GFP_NOFAIL) &&
+ should_fail(fail_page_alloc, 1 << order))
+ return NULL;
+
restart:
z = zonelist->zones; /* the list of zones suitable for gfp_mask */

Index: work-failmalloc/include/linux/should_fail.h
===================================================================
--- work-failmalloc.orig/include/linux/should_fail.h
+++ work-failmalloc/include/linux/should_fail.h
@@ -39,6 +39,10 @@ int setup_should_fail(struct should_fail
extern struct should_fail_data *failslab;
#endif

+#ifdef CONFIG_FAIL_PAGE_ALLOC
+extern struct should_fail_data *fail_page_alloc;
+#endif
+
#else

#define should_fail(data, size) (0)

--