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 <[EMAIL PROTECTED]>
---
Documentation/fault-injection/fault-injection.txt | 5 +++++
mm/page_alloc.c | 12 +++++++++++-
2 files changed, 16 insertions(+), 1 deletion(-)
Index: 2.6-mm/mm/page_alloc.c
===================================================================
--- 2.6-mm.orig/mm/page_alloc.c
+++ 2.6-mm/mm/page_alloc.c
@@ -1168,11 +1168,13 @@ static struct fail_page_alloc_attr {
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 */
@@ -1180,6 +1182,7 @@ static struct fail_page_alloc_attr {
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_wait = 1,
.ignore_gfp_highmem = 1,
+ .min_order = 1,
};
static int __init setup_fail_page_alloc(char *str)
@@ -1190,6 +1193,8 @@ __setup("fail_page_alloc=", setup_fail_p
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))
@@ -1221,12 +1226,17 @@ static int __init fail_page_alloc_debugf
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);
}
Index: 2.6-mm/Documentation/fault-injection/fault-injection.txt
===================================================================
--- 2.6-mm.orig/Documentation/fault-injection/fault-injection.txt
+++ 2.6-mm/Documentation/fault-injection/fault-injection.txt
@@ -103,6 +103,11 @@ configuration of fault-injection capabil
default is 'N', setting it to 'Y' will inject failures
only into non-sleep allocations (GFP_ATOMIC allocations).
+- /debug/fail_page_alloc/min-order:
+
+ specifies the minimum page allocation order to be injected
+ failures.
+
o Boot option
In order to inject faults while debugfs is not available (early boot time),
-
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