Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756548AbbLDRPK (ORCPT ); Fri, 4 Dec 2015 12:15:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:38183 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756506AbbLDRPF (ORCPT ); Fri, 4 Dec 2015 12:15:05 -0500 Subject: Re: [PATCH v3 5/7] mm/compaction: respect compaction order when updating defer counter To: Joonsoo Kim , Andrew Morton References: <1449126681-19647-1-git-send-email-iamjoonsoo.kim@lge.com> <1449126681-19647-6-git-send-email-iamjoonsoo.kim@lge.com> Cc: Mel Gorman , Rik van Riel , David Rientjes , Minchan Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim From: Vlastimil Babka Message-ID: <5661CA16.9010304@suse.cz> Date: Fri, 4 Dec 2015 18:15:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1449126681-19647-6-git-send-email-iamjoonsoo.kim@lge.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: 2644 Lines: 74 On 12/03/2015 08:11 AM, Joonsoo Kim wrote: > It doesn't make sense that we reset defer counter > in compaction_defer_reset() when compaction request under the order of > compact_order_failed succeed. Fix it. Right. > And, it does make sense that giving enough chance for updated failed > order compaction before deferring. Change it. Sorry, can't understand the meaning here. From the code it seems that you want to reset defer_shift to 0 instead of increasing it, when the current order is lower than the failed one? That makes sense, yeah. How about this? "On the other hand, when deferring compaction for an order lower than the current compact_order_failed, we can assume the lower order will recover more quickly, so we should reset the progress made previously on compact_defer_shift with the higher order." > Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka > --- > mm/compaction.c | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index 67b8d90..1a75a6e 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -126,11 +126,14 @@ static struct page *pageblock_pfn_to_page(unsigned long start_pfn, > */ > static void defer_compaction(struct zone *zone, int order) > { > - zone->compact_considered = 0; > - zone->compact_defer_shift++; > - > - if (order < zone->compact_order_failed) > + if (order < zone->compact_order_failed) { > + zone->compact_considered = 0; > + zone->compact_defer_shift = 0; > zone->compact_order_failed = order; > + } else { > + zone->compact_considered = 0; > + zone->compact_defer_shift++; > + } > > if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) > zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; > @@ -161,11 +164,11 @@ bool compaction_deferred(struct zone *zone, int order) > /* Update defer tracking counters after successful compaction of given order */ > static void compaction_defer_reset(struct zone *zone, int order) > { > - zone->compact_considered = 0; > - zone->compact_defer_shift = 0; > - > - if (order >= zone->compact_order_failed) > + if (order >= zone->compact_order_failed) { > + zone->compact_considered = 0; > + zone->compact_defer_shift = 0; > zone->compact_order_failed = order + 1; > + } > > trace_mm_compaction_defer_reset(zone, order); > } > -- 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/