[PATCH 3/4] mm, page_alloc: move might_sleep_if check to the allocator slowpath -revert

From: Mel Gorman
Date: Wed Apr 27 2016 - 08:24:54 EST


Vlastimil Babka pointed out that a patch weakens a zone_reclaim test
which while "safe" defeats the purposes of the debugging check. As most
configurations eliminate this check anyway, I thought it was better to
simply revert the patch instead of adding a second check in zone_reclaim.

This is a revert of the mmotm patch
mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch .

Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 45a36e98b9cb..599bd1a49384 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3606,8 +3606,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
return NULL;
}

- might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
-
/*
* We also sanity check to catch abuse of atomic reserves being used by
* callers that are not in atomic context.
@@ -3806,6 +3804,8 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,

lockdep_trace_alloc(gfp_mask);

+ might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
+
if (should_fail_alloc_page(gfp_mask, order))
return NULL;

--
2.6.4