All of lore.kernel.org
 help / color / mirror / Atom feed
From: Vlastimil Babka <vbabka@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>,
	Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@quantum.com>,
	Olaf Hering <olaf@aepfle.de>, Michal Hocko <mhocko@kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Rik van Riel <riel@redhat.com>,
	Hillf Danton <hillf.zj@alibaba-inc.com>,
	Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable()
Date: Thu, 29 Sep 2016 11:57:01 +0200	[thread overview]
Message-ID: <cadadd38-6456-f58e-504f-cc18ddc47b3f@suse.cz> (raw)
In-Reply-To: <20160926162025.21555-4-vbabka@suse.cz>

On 09/26/2016 06:20 PM, Vlastimil Babka wrote:
> The compaction_zonelist_suitable() function tries to determine if compaction
> will be able to proceed after sufficient reclaim, i.e. whether there are
> enough reclaimable pages to provide enough order-0 freepages for compaction.
> 
> This addition of reclaimable pages to the free pages works well for the order-0
> watermark check, but in the fragmentation index check we only consider truly
> free pages. Thus we can get fragindex value close to 0 which indicates failure
> do to lack of memory, and wrongly decide that compaction won't be suitable even
> after reclaim.
> 
> Instead of trying to somehow adjust fragindex for reclaimable pages, let's just
> skip it from compaction_zonelist_suitable().
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Rik van Riel <riel@redhat.com>

Bah, a fix below, sorry.
----8<----
>From 1cd4855305a9c7eef0cf0c1af9f310cecdcc9406 Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@suse.cz>
Date: Thu, 29 Sep 2016 11:54:07 +0200
Subject: [PATCH] mm, compaction: ignore fragindex from
 compaction_zonelist_suitable()-fix

COMPACT_NOT_SUITABLE_ZONE should not leak outside compaction_suitable() and
we should not skip tracepoint.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/compaction.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index badb92bf14b4..0409a4ad6ea1 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1445,7 +1445,7 @@ enum compact_result compaction_suitable(struct zone *zone, int order,
 	if (ret == COMPACT_CONTINUE && (order > PAGE_ALLOC_COSTLY_ORDER)) {
 		fragindex = fragmentation_index(zone, order);
 		if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
-			return COMPACT_NOT_SUITABLE_ZONE;
+			ret = COMPACT_NOT_SUITABLE_ZONE;
 	}
 
 	trace_mm_compaction_suitable(zone, order, ret);
-- 
2.10.0

WARNING: multiple messages have this Message-ID
From: Vlastimil Babka <vbabka@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>,
	Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@quantum.com>,
	Olaf Hering <olaf@aepfle.de>, Michal Hocko <mhocko@kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Rik van Riel <riel@redhat.com>,
	Hillf Danton <hillf.zj@alibaba-inc.com>,
	Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable()
Date: Thu, 29 Sep 2016 11:57:01 +0200	[thread overview]
Message-ID: <cadadd38-6456-f58e-504f-cc18ddc47b3f@suse.cz> (raw)
In-Reply-To: <20160926162025.21555-4-vbabka@suse.cz>

On 09/26/2016 06:20 PM, Vlastimil Babka wrote:
> The compaction_zonelist_suitable() function tries to determine if compaction
> will be able to proceed after sufficient reclaim, i.e. whether there are
> enough reclaimable pages to provide enough order-0 freepages for compaction.
> 
> This addition of reclaimable pages to the free pages works well for the order-0
> watermark check, but in the fragmentation index check we only consider truly
> free pages. Thus we can get fragindex value close to 0 which indicates failure
> do to lack of memory, and wrongly decide that compaction won't be suitable even
> after reclaim.
> 
> Instead of trying to somehow adjust fragindex for reclaimable pages, let's just
> skip it from compaction_zonelist_suitable().
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Rik van Riel <riel@redhat.com>

Bah, a fix below, sorry.
----8<----

  parent reply	other threads:[~2016-09-29  9:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-26 16:20 [PATCH 0/4] followups to reintroduce compaction feedback for OOM decisions Vlastimil Babka
2016-09-26 16:20 ` Vlastimil Babka
2016-09-26 16:20 ` [PATCH 1/4] mm, compaction: more reliably increase direct compaction priority-fix Vlastimil Babka
2016-09-26 16:20   ` Vlastimil Babka
2016-09-27  3:25   ` Hillf Danton
2016-09-27  3:25     ` Hillf Danton
2016-09-26 16:20 ` [PATCH 2/4] mm, page_alloc: pull no_progress_loops update to should_reclaim_retry() Vlastimil Babka
2016-09-26 16:20   ` Vlastimil Babka
2016-09-26 16:20 ` [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable() Vlastimil Babka
2016-09-26 16:20   ` Vlastimil Babka
2016-09-26 20:15   ` Michal Hocko
2016-09-26 20:15     ` Michal Hocko
2016-09-29  9:57   ` Vlastimil Babka [this message]
2016-09-29  9:57     ` Vlastimil Babka
2016-09-26 16:20 ` [PATCH 4/4] mm, compaction: restrict fragindex to costly orders Vlastimil Babka
2016-09-26 16:20   ` Vlastimil Babka
2016-09-26 20:29   ` Michal Hocko
2016-09-26 20:29     ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=cadadd38-6456-f58e-504f-cc18ddc47b3f@suse.cz \
    --to=vbabka@suse.cz \
    --cc=Ralf-Peter.Rohbeck@quantum.com \
    --cc=a.miskiewicz@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=hillf.zj@alibaba-inc.com \
    --cc=iamjoonsoo.kim@lge.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@techsingularity.net \
    --cc=mhocko@kernel.org \
    --cc=mhocko@suse.com \
    --cc=olaf@aepfle.de \
    --cc=riel@redhat.com \
    --cc=rientjes@google.com \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [PATCH 3/4] mm, compaction: ignore fragindex from compaction_zonelist_suitable()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.