From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752124Ab2HMMOu (ORCPT ); Mon, 13 Aug 2012 08:14:50 -0400 Received: from mga02.intel.com ([134.134.136.20]:30186 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751999Ab2HMMOt (ORCPT ); Mon, 13 Aug 2012 08:14:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,759,1336374000"; d="scan'208";a="185678018" From: Alex Shi To: mgorman@suse.de, cl@linux.com Cc: davem@davemloft.net, a.p.zijlstra@chello.nl, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, alex.shi@intel.com Subject: [PATCH] mm: correct page->pfmemalloc to fix deactivate_slab regression Date: Mon, 13 Aug 2012 20:14:35 +0800 Message-Id: <1344860075-31752-1-git-send-email-alex.shi@intel.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit cfd19c5a9ec (mm: only set page->pfmemalloc when ALLOC_NO_WATERMARKS was used) try to narrow down page->pfmemalloc setting, but it missed some places the pfmemalloc should be set. So, in __slab_alloc, the unalignment pfmemalloc and ALLOC_NO_WATERMARKS cause incorrect deactivate_slab() on our core2 server: 64.73% fio [kernel.kallsyms] [k] _raw_spin_lock | --- _raw_spin_lock | |---0.34%-- deactivate_slab | __slab_alloc | kmem_cache_alloc | | That causes our fio sync write performance has 40% regression. This patch move the checking in get_page_from_freelist, that resolved this issue. Signed-off-by: Alex Shi --- mm/page_alloc.c | 21 +++++++++++---------- 1 files changed, 11 insertions(+), 10 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 009ac28..07f1924 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1928,6 +1928,17 @@ this_zone_full: zlc_active = 0; goto zonelist_scan; } + + 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 = !!(alloc_flags & ALLOC_NO_WATERMARKS); + return page; } @@ -2389,14 +2400,6 @@ rebalance: zonelist, high_zoneidx, nodemask, preferred_zone, migratetype); 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; } } @@ -2569,8 +2572,6 @@ retry_cpuset: page = __alloc_pages_slowpath(gfp_mask, order, zonelist, high_zoneidx, nodemask, preferred_zone, migratetype); - else - page->pfmemalloc = false; trace_mm_page_alloc(page, order, gfp_mask, migratetype); -- 1.7.5.4