[133/181] mm/page_alloc.c: micro-optimization remove unnecessary branch

Commit Message

Andrew Morton Oct. 13, 2020, 11:55 p.m. UTC

From: Mateusz Nosek <[e-mail]>
Subject: mm/page_alloc.c: micro-optimization remove unnecessary branch

Previously flags check was separated into two separated checks with two
separated branches. In case of presence of any of two mentioned flags,
the same effect on flow occurs. Therefore checks can be merged and one
branch can be avoided.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Mateusz Nosek <[e-mail]>
Reviewed-by: Andrew Morton <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Patch

--- a/mm/page_alloc.c~mm-page_allocc-micro-optimization-remove-unnecessary-branch
+++ a/mm/page_alloc.c
@@ -3986,8 +3986,10 @@  __alloc_pages_may_oom(gfp_t gfp_mask, un
 	 * success so it is time to admit defeat. We will skip the OOM killer
 	 * because it is very likely that the caller has a more reasonable
 	 * fallback than shooting a random task.
+	 *
+	 * The OOM killer may not free memory on a specific node.
 	 */
-	if (gfp_mask & __GFP_RETRY_MAYFAIL)
+	if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
 		goto out;
 	/* The OOM killer does not needlessly kill tasks for lowmem */
 	if (ac->highest_zoneidx < ZONE_NORMAL)
@@ -4004,10 +4006,6 @@  __alloc_pages_may_oom(gfp_t gfp_mask, un
 	 * failures more gracefully we should just bail out here.
 	 */
 
-	/* The OOM killer may not free memory on a specific node */
-	if (gfp_mask & __GFP_THISNODE)
-		goto out;
-
 	/* Exhausted what can be done so it's blame time */
 	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
 		*did_some_progress = 1;