From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760490AbbLCOqw (ORCPT ); Thu, 3 Dec 2015 09:46:52 -0500 Received: from sci-ig2.spreadtrum.com ([222.66.158.135]:45597 "EHLO SHSQR01.spreadtrum.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752472AbbLCOqu convert rfc822-to-8bit (ORCPT ); Thu, 3 Dec 2015 09:46:50 -0500 From: "Pradeep Goswami (Pradeep Kumar Goswami)" To: Michal Hocko CC: "rebecca@android.com" , "vdavydov@parallels.com" , "akpm@linux-foundation.org" , "vbabka@suse.cz" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "sanjeev.yadav@spreatrum.com" Subject: Re: [PATCH]mm:Correctly update number of rotated pages on active list. Thread-Topic: [PATCH]mm:Correctly update number of rotated pages on active list. Thread-Index: AQHRLbKESA6uxeFogkiM7AmaX6CY7p64kfIAgAA/RAA= Date: Thu, 3 Dec 2015 14:46:20 +0000 Message-ID: <20151203144614.GA4907@pradeepkumarubtnb.spreadtrum.com> References: <20151203100809.GA4544@pradeepkumarubtnb.spreadtrum.com> <20151203105948.GE9264@dhcp22.suse.cz> In-Reply-To: <20151203105948.GE9264@dhcp22.suse.cz> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.8.1.75] Content-Type: text/plain; charset="us-ascii" Content-ID: <8D6B9A443AA60146A2581DD64F123514@spreadtrum.com> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-MAIL: SHSQR01.spreadtrum.com tB3EkeOC082313 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 03, 2015 at 11:59:48AM +0100, Michal Hocko wrote: > On Thu 03-12-15 10:08:11, Pradeep Goswami (Pradeep Kumar Goswami) wrote: > > This patch corrects the number of pages which are rotated on active list. > > The counter for rotated pages effects the number of pages > > to be scanned on active pages list in low memory situations. > > Why this should be changed? > > This seems to be deliberate: > /* > * Count referenced pages from currently used mappings as rotated, > * even though only some of them are actually re-activated. This > * helps balance scan pressure between file and anonymous pages in > * get_scan_count. > */ > reclaim_stat->recent_rotated[file] += nr_rotated; > > What kind of problem are you trying to fix? Actually the numeber of pages which are actually rotated are wrongly updated, So I thought this might be minor coding error but as pointed out above, this seems to be deliberate. Thanks for clarifying. > > > > > Signed-off-by: Pradeep Goswami > > Cc: Rebecca Schultz Zavin > > Cc: Vladimir Davydov > > Cc: Andrew Morton > > --- > > --- a/mm/vmscan.c 2015-11-18 20:55:38.208838142 +0800 > > +++ b/mm/vmscan.c 2015-11-19 14:37:31.189838998 +0800 > > @@ -1806,7 +1806,6 @@ static void shrink_active_list(unsigned > > > > if (page_referenced(page, 0, sc->target_mem_cgroup, > > &vm_flags)) { > > - nr_rotated += hpage_nr_pages(page); > > /* > > * Identify referenced, file-backed active pages and > > * give them one more trip around the active list. So > > @@ -1818,6 +1817,7 @@ static void shrink_active_list(unsigned > > */ > > if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { > > list_add(&page->lru, &l_active); > > + nr_rotated += hpage_nr_pages(page); > > continue; > > } > > } > > > > Thanks, > > Pradeep. > > -- > > To unsubscribe, send a message with 'unsubscribe linux-mm' in > > the body to majordomo@kvack.org. For more info on Linux MM, > > see: http://www.linux-mm.org/ . > > Don't email: email@kvack.org > > -- > Michal Hocko > SUSE Labs