fault-injection: add min-order parameter to fail_page_alloc
Limiting smaller allocation failures by fault injection helps to find real
possible bugs. Because higher order allocations are likely to fail and
zero-order allocations are not likely to fail.
This patch adds min-order parameter to fail_page_alloc. It specifies the
minimum page allocation order to be injected failures.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 297efcf..f9e4e64 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -900,11 +900,13 @@
u32 ignore_gfp_highmem;
u32 ignore_gfp_wait;
+ u32 min_order;
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
struct dentry *ignore_gfp_highmem_file;
struct dentry *ignore_gfp_wait_file;
+ struct dentry *min_order_file;
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
@@ -912,6 +914,7 @@
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_wait = 1,
.ignore_gfp_highmem = 1,
+ .min_order = 1,
};
static int __init setup_fail_page_alloc(char *str)
@@ -922,6 +925,8 @@
static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
+ if (order < fail_page_alloc.min_order)
+ return 0;
if (gfp_mask & __GFP_NOFAIL)
return 0;
if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
@@ -953,12 +958,17 @@
fail_page_alloc.ignore_gfp_highmem_file =
debugfs_create_bool("ignore-gfp-highmem", mode, dir,
&fail_page_alloc.ignore_gfp_highmem);
+ fail_page_alloc.min_order_file =
+ debugfs_create_u32("min-order", mode, dir,
+ &fail_page_alloc.min_order);
if (!fail_page_alloc.ignore_gfp_wait_file ||
- !fail_page_alloc.ignore_gfp_highmem_file) {
+ !fail_page_alloc.ignore_gfp_highmem_file ||
+ !fail_page_alloc.min_order_file) {
err = -ENOMEM;
debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
+ debugfs_remove(fail_page_alloc.min_order_file);
cleanup_fault_attr_dentries(&fail_page_alloc.attr);
}