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Message-Id: <1340184920-22288-6-git-send-email-mgorman@suse.de>
Date: Wed, 20 Jun 2012 10:35:08 +0100
From: Mel Gorman <mgorman@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Linux-MM <linux-mm@...ck.org>,
Linux-Netdev <netdev@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
David Miller <davem@...emloft.net>, Neil Brown <neilb@...e.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Mike Christie <michaelc@...wisc.edu>,
Eric B Munson <emunson@...bm.net>,
Mel Gorman <mgorman@...e.de>
Subject: [PATCH 05/17] mm: Only set page->pfmemalloc when ALLOC_NO_WATERMARKS was used
__alloc_pages_slowpath() is called when the number of free pages is below
the low watermark. If the caller is entitled to use ALLOC_NO_WATERMARKS
then the page will be marked page->pfmemalloc. This protects more pages
than are strictly necessary as we only need to protect pages allocated
below the min watermark (the pfmemalloc reserves).
This patch only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was
required to allocate the page.
[rientjes@...gle.com: David noticed the problem during review]
Signed-off-by: Mel Gorman <mgorman@...e.de>
---
mm/page_alloc.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c059f51..e6c68d3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2087,8 +2087,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
page = get_page_from_freelist(gfp_mask, nodemask,
order, zonelist, high_zoneidx,
- alloc_flags, preferred_zone,
- migratetype);
+ alloc_flags & ~ALLOC_NO_WATERMARKS,
+ preferred_zone, migratetype);
if (page) {
preferred_zone->compact_considered = 0;
preferred_zone->compact_defer_shift = 0;
@@ -2180,8 +2180,8 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
retry:
page = get_page_from_freelist(gfp_mask, nodemask, order,
zonelist, high_zoneidx,
- alloc_flags, preferred_zone,
- migratetype);
+ alloc_flags & ~ALLOC_NO_WATERMARKS,
+ preferred_zone, migratetype);
/*
* If an allocation failed after direct reclaim, it could be because
@@ -2352,8 +2352,17 @@ rebalance:
page = __alloc_pages_high_priority(gfp_mask, order,
zonelist, high_zoneidx, nodemask,
preferred_zone, migratetype);
- if (page)
+ if (page) {
+ /*
+ * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
+ * necessary to allocate the page. The expectation is
+ * that the caller is taking steps that will free more
+ * memory. The caller should avoid the page being used
+ * for !PFMEMALLOC purposes.
+ */
+ page->pfmemalloc = true;
goto got_pg;
+ }
}
/* Atomic allocations - we can't balance anything */
@@ -2470,14 +2479,6 @@ nopage:
warn_alloc_failed(gfp_mask, order, NULL);
return page;
got_pg:
- /*
- * page->pfmemalloc is set when the caller had PFMEMALLOC set, is
- * been OOM killed or specified __GFP_MEMALLOC. The expectation is
- * that the caller is taking steps that will free more memory. The
- * caller should avoid the page being used for !PFMEMALLOC purposes.
- */
- page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
-
if (kmemcheck_enabled)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);
--
1.7.9.2
--
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