From cfd19c5a9ecf8e5e38de2603077c4330af21316e Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:44:10 -0700 Subject: [PATCH] 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@google.com: David noticed the problem during review] Signed-off-by: Mel Gorman Cc: David Miller Cc: Neil Brown Cc: Peter Zijlstra Cc: Mike Christie Cc: Eric B Munson Cc: Eric Dumazet Cc: Sebastian Andrzej Siewior Cc: Mel Gorman Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 cd5390f2f18d..f9d925451bfd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2116,8 +2116,8 @@ __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; @@ -2209,8 +2209,8 @@ __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 @@ -2381,8 +2381,17 @@ 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 */ @@ -2499,14 +2508,6 @@ 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); -- 2.20.1