Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751760Ab3HZNBr (ORCPT ); Mon, 26 Aug 2013 09:01:47 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:36007 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558Ab3HZNBq (ORCPT ); Mon, 26 Aug 2013 09:01:46 -0400 From: "Aneesh Kumar K.V" To: Joonsoo Kim 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 In-Reply-To: <20130822074752.GH13415@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> User-Agent: Notmuch/0.15.2+167~g5306b2b (http://notmuchmail.org) Emacs/24.3.50.1 (x86_64-unknown-linux-gnu) Date: Mon, 26 Aug 2013 18:31:35 +0530 Message-ID: <871u5gehcg.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13082612-2000-0000-0000-00000D7644C1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1846 Lines: 52 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 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 -aneesh -- 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/