[PATCH 74/97] mm: page_alloc: only check the alloc flags and gfp_mask for dirty once

From: Mel Gorman
Date: Thu Aug 28 2014 - 14:48:33 EST


commit a6e21b14f22041382e832d30deda6f26f37b1097 upstream.

Currently it's calculated once per zone in the zonelist.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
mm/page_alloc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e7ec3c..cb4cadd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1915,6 +1915,8 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
int zlc_active = 0; /* set if using zonelist_cache */
int did_zlc_setup = 0; /* just call zlc_setup() one time */
+ bool consider_zone_dirty = (alloc_flags & ALLOC_WMARK_LOW) &&
+ (gfp_mask & __GFP_WRITE);

zonelist_scan:
/*
@@ -1973,8 +1975,7 @@ zonelist_scan:
* will require awareness of zones in the
* dirty-throttling and the flusher threads.
*/
- if ((alloc_flags & ALLOC_WMARK_LOW) &&
- (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
+ if (consider_zone_dirty && !zone_dirty_ok(zone))
continue;

mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
--
1.8.4.5

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