Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753102Ab3H0Hjx (ORCPT ); Tue, 27 Aug 2013 03:39:53 -0400 Received: from lgeamrelo02.lge.com ([156.147.1.126]:57042 "EHLO LGEAMRELO02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753070Ab3H0Hjw (ORCPT ); Tue, 27 Aug 2013 03:39:52 -0400 X-AuditID: 9c93017e-b7c76ae000003897-5b-521c57c6c641 Date: Tue, 27 Aug 2013 16:40:17 +0900 From: Joonsoo Kim To: "Aneesh Kumar K.V" Cc: Andrew Morton , Rik van Riel , Mel Gorman , Michal Hocko , KAMEZAWA Hiroyuki , Hugh Dickins , Davidlohr Bueso , David Gibson , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li , Naoya Horiguchi , Hillf Danton Subject: Re: [PATCH v2 03/20] mm, hugetlb: fix subpool accounting handling Message-ID: <20130827074016.GA6795@lge.com> References: <1376040398-11212-1-git-send-email-iamjoonsoo.kim@lge.com> <1376040398-11212-4-git-send-email-iamjoonsoo.kim@lge.com> <87vc2zgzpn.fsf@linux.vnet.ibm.com> <20130822065038.GA13415@lge.com> <87y57u19ur.fsf@linux.vnet.ibm.com> <20130822074752.GH13415@lge.com> <871u5gehcg.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871u5gehcg.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2007 Lines: 55 On Mon, Aug 26, 2013 at 06:31:35PM +0530, Aneesh Kumar K.V wrote: > Joonsoo Kim writes: > > > On Thu, Aug 22, 2013 at 12:38:12PM +0530, Aneesh Kumar K.V wrote: > >> Joonsoo Kim writes: > >> > >> > Hello, Aneesh. > >> > > >> > First of all, thank you for review! > >> > > >> > On Wed, Aug 21, 2013 at 02:58:20PM +0530, Aneesh Kumar K.V wrote: > >> >> Joonsoo Kim writes: > >> >> > >> >> > If we alloc hugepage with avoid_reserve, we don't dequeue reserved one. > >> >> > So, we should check subpool counter when avoid_reserve. > >> >> > This patch implement it. > >> >> > >> >> Can you explain this better ? ie, if we don't have a reservation in the > >> >> area chg != 0. So why look at avoid_reserve. > >> > > >> > We don't consider avoid_reserve when chg != 0. > >> > Look at following code. > >> > > >> > + if (chg || avoid_reserve) > >> > + if (hugepage_subpool_get_pages(spool, 1)) > >> > > >> > It means that if chg != 0, we skip to check avoid_reserve. > >> > >> when whould be avoid_reserve == 1 and chg == 0 ? > > > > In this case, we should do hugepage_subpool_get_pages(), since we don't > > get a reserved page due to avoid_reserve. > > As per off-list discussion we had around this, please add additional > information in commit message explaining when we have > avoid_reserve == 1 and chg == 0 Okay! > > Something like the below copied from call site. > > /* If the process that created a MAP_PRIVATE mapping is about to > * perform a COW due to a shared page count, attempt to satisfy > * the allocation without using the existing reserves > */ > > Reviewed-by: Aneesh Kumar K.V Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/