On 07/20/2015 10:00 AM, Mel Gorman wrote:
From: Mel Gorman <mgorman@xxxxxxx>
File-backed pages that will be immediately dirtied are balanced between
zones but it's unnecessarily expensive. Move consider_zone_balanced into
the alloc_context instead of checking bitmaps multiple times.
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Agreed with new ac->spread_dirty_page name (or rather plural,
spread_dirty_pages?) , and a nitpick below.
---
mm/internal.h | 1 +
mm/page_alloc.c | 9 ++++++---
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/internal.h b/mm/internal.h
index 36b23f1e2ca6..8977348fbeec 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -129,6 +129,7 @@ struct alloc_context {
int classzone_idx;
int migratetype;
enum zone_type high_zoneidx;
+ bool consider_zone_dirty;
};
/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4b35b196aeda..7c2dc022f4ba 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2295,8 +2295,6 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
struct zoneref *z;
struct page *page = NULL;
struct zone *zone;
- bool consider_zone_dirty = (alloc_flags & ALLOC_WMARK_LOW) &&
- (gfp_mask & __GFP_WRITE);
int nr_fair_skipped = 0;
bool zonelist_rescan;
@@ -2355,7 +2353,7 @@ zonelist_scan:
I've been recently suggested by mhocko to add to ~/.gitconfig
[diff "default"]
xfuncname = "^[[:alpha:]$_].*[^:]$"
So that git produces function names in hunk context instead of labels. I
gladly spread this arcane knowledge :)
* will require awareness of zones in the
* dirty-throttling and the flusher threads.
*/
This comment (in the part not shown) mentions ALLOC_WMARK_LOW as the
mechanism to distinguish fastpath from slowpath. This is no longer true,
so update it too?
- if (consider_zone_dirty && !zone_dirty_ok(zone))
+ if (ac->consider_zone_dirty && !zone_dirty_ok(zone))
continue;
mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
@@ -2995,6 +2993,10 @@ retry_cpuset:
/* We set it here, as __alloc_pages_slowpath might have changed it */
ac.zonelist = zonelist;
+
+ /* Dirty zone balancing only done in the fast path */
+ ac.consider_zone_dirty = (gfp_mask & __GFP_WRITE);
+
/* The preferred zone is used for statistics later */
preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx,
ac.nodemask, &ac.preferred_zone);
@@ -3012,6 +3014,7 @@ retry_cpuset:
* complete.
*/
alloc_mask = memalloc_noio_flags(gfp_mask);
+ ac.consider_zone_dirty = false;
page = __alloc_pages_slowpath(alloc_mask, order, &ac);
}
--
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