Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751348AbaFWH24 (ORCPT ); Mon, 23 Jun 2014 03:28:56 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38583 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722AbaFWH2z (ORCPT ); Mon, 23 Jun 2014 03:28:55 -0400 Date: Mon, 23 Jun 2014 09:28:50 +0200 From: Michal Hocko To: Johannes Weiner Cc: Vlastimil Babka , Andrew Morton , Mel Gorman , Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch 2/4] mm: vmscan: rework compaction-ready signaling in direct reclaim Message-ID: <20140623072850.GA9743@dhcp22.suse.cz> References: <1403282030-29915-1-git-send-email-hannes@cmpxchg.org> <1403282030-29915-2-git-send-email-hannes@cmpxchg.org> <53A467A3.1050008@suse.cz> <20140620202449.GA30849@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140620202449.GA30849@cmpxchg.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 20-06-14 16:24:49, Johannes Weiner wrote: [...] > From cd48b73fdca9e23aa21f65e9af1f850dbac5ab8e Mon Sep 17 00:00:00 2001 > From: Johannes Weiner > Date: Wed, 11 Jun 2014 12:53:59 -0400 > Subject: [patch] mm: vmscan: rework compaction-ready signaling in direct > reclaim > > Page reclaim for a higher-order page runs until compaction is ready, > then aborts and signals this situation through the return value of > shrink_zones(). This is an oddly specific signal to encode in the > return value of shrink_zones(), though, and can be quite confusing. > > Introduce sc->compaction_ready and signal the compactability of the > zones out-of-band to free up the return value of shrink_zones() for > actual zone reclaimability. > > Signed-off-by: Johannes Weiner > Acked-by: Vlastimil Babka Very nice. It will help me to get rid off additional hacks for the min_limit for memcg. Thanks! One question below [...] > @@ -2500,12 +2492,15 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup, > sc->priority); > sc->nr_scanned = 0; > - aborted_reclaim = shrink_zones(zonelist, sc); > + shrink_zones(zonelist, sc); > > total_scanned += sc->nr_scanned; > if (sc->nr_reclaimed >= sc->nr_to_reclaim) > goto out; > > + if (sc->compaction_ready) > + goto out; > + > /* > * If we're getting trouble reclaiming, start doing > * writepage even in laptop mode. > @@ -2526,7 +2521,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > WB_REASON_TRY_TO_FREE_PAGES); > sc->may_writepage = 1; > } > - } while (--sc->priority >= 0 && !aborted_reclaim); > + } while (--sc->priority >= 0); > > out: > delayacct_freepages_end(); It is not entirely clear to me why we do not need to check and wake up flusher threads anymore? -- Michal Hocko SUSE Labs -- 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/