Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932163AbbG1M0F (ORCPT ); Tue, 28 Jul 2015 08:26:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:43898 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754386AbbG1M0D (ORCPT ); Tue, 28 Jul 2015 08:26:03 -0400 Subject: Re: [PATCH 03/10] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing To: Mel Gorman , Linux-MM References: <1437379219-9160-1-git-send-email-mgorman@suse.com> <1437379219-9160-4-git-send-email-mgorman@suse.com> Cc: Johannes Weiner , Rik van Riel , Pintu Kumar , Xishi Qiu , Gioh Kim , LKML , Mel Gorman From: Vlastimil Babka Message-ID: <55B774D5.8030600@suse.cz> Date: Tue, 28 Jul 2015 14:25:57 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <1437379219-9160-4-git-send-email-mgorman@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3055 Lines: 93 On 07/20/2015 10:00 AM, Mel Gorman wrote: > From: Mel Gorman > > File-backed pages that will be immediately dirtied are balanced between > zones but it's unnecessarily expensive. Move consider_zone_balanced into > the alloc_context instead of checking bitmaps multiple times. > > Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Agreed with new ac->spread_dirty_page name (or rather plural, spread_dirty_pages?) , and a nitpick below. > --- > mm/internal.h | 1 + > mm/page_alloc.c | 9 ++++++--- > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 36b23f1e2ca6..8977348fbeec 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -129,6 +129,7 @@ struct alloc_context { > int classzone_idx; > int migratetype; > enum zone_type high_zoneidx; > + bool consider_zone_dirty; > }; > > /* > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 4b35b196aeda..7c2dc022f4ba 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2295,8 +2295,6 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > struct zoneref *z; > struct page *page = NULL; > struct zone *zone; > - bool consider_zone_dirty = (alloc_flags & ALLOC_WMARK_LOW) && > - (gfp_mask & __GFP_WRITE); > int nr_fair_skipped = 0; > bool zonelist_rescan; > > @@ -2355,7 +2353,7 @@ zonelist_scan: I've been recently suggested by mhocko to add to ~/.gitconfig [diff "default"] xfuncname = "^[[:alpha:]$_].*[^:]$" So that git produces function names in hunk context instead of labels. I gladly spread this arcane knowledge :) > * will require awareness of zones in the > * dirty-throttling and the flusher threads. > */ This comment (in the part not shown) mentions ALLOC_WMARK_LOW as the mechanism to distinguish fastpath from slowpath. This is no longer true, so update it too? > - if (consider_zone_dirty && !zone_dirty_ok(zone)) > + if (ac->consider_zone_dirty && !zone_dirty_ok(zone)) > continue; > > mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK]; > @@ -2995,6 +2993,10 @@ retry_cpuset: > > /* We set it here, as __alloc_pages_slowpath might have changed it */ > ac.zonelist = zonelist; > + > + /* Dirty zone balancing only done in the fast path */ > + ac.consider_zone_dirty = (gfp_mask & __GFP_WRITE); > + > /* The preferred zone is used for statistics later */ > preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx, > ac.nodemask, &ac.preferred_zone); > @@ -3012,6 +3014,7 @@ retry_cpuset: > * complete. > */ > alloc_mask = memalloc_noio_flags(gfp_mask); > + ac.consider_zone_dirty = false; > > page = __alloc_pages_slowpath(alloc_mask, order, &ac); > } > -- 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/