[PATCH] vmscan: remove painful micro optimization

[KOSAKI Motohiro]

Currently, __alloc_pages_direct_reclaim() call get_page_from_freelist()
only if try_to_free_pages() return !0.

It's no necessary micro optimization becauase "return 0" mean vmscan reached
priority 0 and didn't get any pages, iow, it's really slow path. But also it
has bad side effect. If we don't call drain_all_pages(), we have a chance to
get infinite loop.

This patch remove its bad and meaningless micro optimization.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
 mm/page_alloc.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1572079..c41d488 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1950,9 +1950,6 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,

 	cond_resched();

-	if (unlikely(!(*did_some_progress)))
-		return NULL;
-
 retry:
 	page = get_page_from_freelist(gfp_mask, nodemask, order,
 					zonelist, high_zoneidx,
-- 
1.7.3.1




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