From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by kanga.kvack.org (Postfix) with ESMTP id 445406B0253 for ; Tue, 28 Jul 2015 08:26:05 -0400 (EDT) Received: by wibud3 with SMTP id ud3so178428175wib.1 for ; Tue, 28 Jul 2015 05:26:04 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id k8si20077848wia.75.2015.07.28.05.26.03 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 28 Jul 2015 05:26:03 -0700 (PDT) Subject: Re: [PATCH 03/10] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing References: <1437379219-9160-1-git-send-email-mgorman@suse.com> <1437379219-9160-4-git-send-email-mgorman@suse.com> From: Vlastimil Babka Message-ID: <55B774D5.8030600@suse.cz> Date: Tue, 28 Jul 2015 14:25:57 +0200 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: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Linux-MM Cc: Johannes Weiner , Rik van Riel , Pintu Kumar , Xishi Qiu , Gioh Kim , LKML , Mel Gorman 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, 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