From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753968AbZDVANZ (ORCPT ); Tue, 21 Apr 2009 20:13:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753425AbZDVANP (ORCPT ); Tue, 21 Apr 2009 20:13:15 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:60223 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753371AbZDVANO (ORCPT ); Tue, 21 Apr 2009 20:13:14 -0400 From: KOSAKI Motohiro To: Mel Gorman Subject: Re: [PATCH 18/25] Do not disable interrupts in free_page_mlock() Cc: kosaki.motohiro@jp.fujitsu.com, Linux Memory Management List , Christoph Lameter , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra , Pekka Enberg , Andrew Morton , Lee Schermerhorn In-Reply-To: <1240266011-11140-19-git-send-email-mel@csn.ul.ie> References: <1240266011-11140-1-git-send-email-mel@csn.ul.ie> <1240266011-11140-19-git-send-email-mel@csn.ul.ie> Message-Id: <20090422091144.626B.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50 [ja] Date: Wed, 22 Apr 2009 09:13:10 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (cc to Lee) > free_page_mlock() tests and clears PG_mlocked using locked versions of the > bit operations. If set, it disables interrupts to update counters and this > happens on every page free even though interrupts are disabled very shortly > afterwards a second time. This is wasteful. > > This patch splits what free_page_mlock() does. The bit check is still > made. However, the update of counters is delayed until the interrupts are > disabled and the non-lock version for clearing the bit is used. One potential > weirdness with this split is that the counters do not get updated if the > bad_page() check is triggered but a system showing bad pages is getting > screwed already. Looks good. thanks good improvement. I hope Lee also ack this. Reviewed-by: KOSAKI Motohiro -kosaki > > Signed-off-by: Mel Gorman > Reviewed-by: Christoph Lameter > --- > mm/internal.h | 11 +++-------- > mm/page_alloc.c | 8 +++++++- > 2 files changed, 10 insertions(+), 9 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 987bb03..58ec1bc 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -157,14 +157,9 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page) > */ > static inline void free_page_mlock(struct page *page) > { > - if (unlikely(TestClearPageMlocked(page))) { > - unsigned long flags; > - > - local_irq_save(flags); > - __dec_zone_page_state(page, NR_MLOCK); > - __count_vm_event(UNEVICTABLE_MLOCKFREED); > - local_irq_restore(flags); > - } > + __ClearPageMlocked(page); > + __dec_zone_page_state(page, NR_MLOCK); > + __count_vm_event(UNEVICTABLE_MLOCKFREED); > } > > #else /* CONFIG_HAVE_MLOCKED_PAGE_BIT */ > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index a1ca038..bf4b8d9 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -499,7 +499,6 @@ static inline void __free_one_page(struct page *page, > > static inline int free_pages_check(struct page *page) > { > - free_page_mlock(page); > if (unlikely(page_mapcount(page) | > (page->mapping != NULL) | > (page_count(page) != 0) | > @@ -556,6 +555,7 @@ static void __free_pages_ok(struct page *page, unsigned int order) > unsigned long flags; > int i; > int bad = 0; > + int clearMlocked = PageMlocked(page); > > for (i = 0 ; i < (1 << order) ; ++i) > bad += free_pages_check(page + i); > @@ -571,6 +571,8 @@ static void __free_pages_ok(struct page *page, unsigned int order) > kernel_map_pages(page, 1 << order, 0); > > local_irq_save(flags); > + if (unlikely(clearMlocked)) > + free_page_mlock(page); > __count_vm_events(PGFREE, 1 << order); > free_one_page(page_zone(page), page, order, > get_pageblock_migratetype(page)); > @@ -1018,6 +1020,7 @@ static void free_hot_cold_page(struct page *page, int cold) > struct zone *zone = page_zone(page); > struct per_cpu_pages *pcp; > unsigned long flags; > + int clearMlocked = PageMlocked(page); > > if (PageAnon(page)) > page->mapping = NULL; > @@ -1033,7 +1036,10 @@ static void free_hot_cold_page(struct page *page, int cold) > > pcp = &zone_pcp(zone, get_cpu())->pcp; > local_irq_save(flags); > + if (unlikely(clearMlocked)) > + free_page_mlock(page); > __count_vm_event(PGFREE); > + > if (cold) > list_add_tail(&page->lru, &pcp->list); > else > -- > 1.5.6.5 >