All of lore.kernel.org
 help / color / mirror / Atom feed
From: Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>,
	Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@quantum.com>,
	Olaf Hering <olaf@aepfle.de>
Cc: linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@techsingularity.net>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>
Subject: [PATCH 2/4] mm, compaction: more reliably increase direct compaction priority
Date: Tue,  6 Sep 2016 15:52:56 +0200	[thread overview]
Message-ID: <20160906135258.18335-3-vbabka@suse.cz> (raw)
In-Reply-To: <20160906135258.18335-1-vbabka@suse.cz>

During reclaim/compaction loop, compaction priority can be increased by the
should_compact_retry() function, but the current code is not optimal. Priority
is only increased when compaction_failed() is true, which means that compaction
has scanned the whole zone. This may not happen even after multiple attempts
with a lower priority due to parallel activity, so we might needlessly
struggle on the lower priorities and possibly run out of compaction retry
attempts in the process.

After this patch we are guaranteed at least one attempt at the highest
compaction priority even if we exhaust all retries at the lower priorities.

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>
---
 mm/page_alloc.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1df7694f4ec7..f8bed910e3cf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3174,13 +3174,8 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
 	 * so it doesn't really make much sense to retry except when the
 	 * failure could be caused by insufficient priority
 	 */
-	if (compaction_failed(compact_result)) {
-		if (*compact_priority > MIN_COMPACT_PRIORITY) {
-			(*compact_priority)--;
-			return true;
-		}
-		return false;
-	}
+	if (compaction_failed(compact_result))
+		goto check_priority;
 
 	/*
 	 * make sure the compaction wasn't deferred or didn't bail out early
@@ -3204,6 +3199,15 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
 	if (compaction_retries <= max_retries)
 		return true;
 
+	/*
+	 * Make sure there is at least one attempt at the highest priority
+	 * if we exhausted all retries at the lower priorities
+	 */
+check_priority:
+	if (*compact_priority > MIN_COMPACT_PRIORITY) {
+		(*compact_priority)--;
+		return true;
+	}
 	return false;
 }
 #else
-- 
2.9.3

WARNING: multiple messages have this Message-ID
From: Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>,
	Ralf-Peter Rohbeck <Ralf-Peter.Rohbeck@quantum.com>,
	Olaf Hering <olaf@aepfle.de>
Cc: linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@techsingularity.net>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>
Subject: [PATCH 2/4] mm, compaction: more reliably increase direct compaction priority
Date: Tue,  6 Sep 2016 15:52:56 +0200	[thread overview]
Message-ID: <20160906135258.18335-3-vbabka@suse.cz> (raw)
In-Reply-To: <20160906135258.18335-1-vbabka@suse.cz>

During reclaim/compaction loop, compaction priority can be increased by the
should_compact_retry() function, but the current code is not optimal. Priority
is only increased when compaction_failed() is true, which means that compaction
has scanned the whole zone. This may not happen even after multiple attempts
with a lower priority due to parallel activity, so we might needlessly
struggle on the lower priorities and possibly run out of compaction retry
attempts in the process.

After this patch we are guaranteed at least one attempt at the highest
compaction priority even if we exhaust all retries at the lower priorities.

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>
---
 mm/page_alloc.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1df7694f4ec7..f8bed910e3cf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3174,13 +3174,8 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
 	 * so it doesn't really make much sense to retry except when the
 	 * failure could be caused by insufficient priority
 	 */
-	if (compaction_failed(compact_result)) {
-		if (*compact_priority > MIN_COMPACT_PRIORITY) {
-			(*compact_priority)--;
-			return true;
-		}
-		return false;
-	}
+	if (compaction_failed(compact_result))
+		goto check_priority;
 
 	/*
 	 * make sure the compaction wasn't deferred or didn't bail out early
@@ -3204,6 +3199,15 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
 	if (compaction_retries <= max_retries)
 		return true;
 
+	/*
+	 * Make sure there is at least one attempt at the highest priority
+	 * if we exhausted all retries at the lower priorities
+	 */
+check_priority:
+	if (*compact_priority > MIN_COMPACT_PRIORITY) {
+		(*compact_priority)--;
+		return true;
+	}
 	return false;
 }
 #else
-- 
2.9.3

--
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply	other threads:[~2016-09-06 13:53 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-06 13:52 [PATCH 0/4] reintroduce compaction feedback for OOM decisions Vlastimil Babka
2016-09-06 13:52 ` Vlastimil Babka
2016-09-06 13:52 ` [PATCH 1/4] Revert "mm, oom: prevent premature OOM killer invocation for high order request" Vlastimil Babka
2016-09-06 13:52   ` Vlastimil Babka
2016-09-21 17:04   ` Michal Hocko
2016-09-21 17:04     ` Michal Hocko
2016-09-06 13:52 ` Vlastimil Babka [this message]
2016-09-06 13:52   ` [PATCH 2/4] mm, compaction: more reliably increase direct compaction priority Vlastimil Babka
2016-09-21 17:13   ` Michal Hocko
2016-09-21 17:13     ` Michal Hocko
2016-09-22 12:51     ` Vlastimil Babka
2016-09-22 12:51       ` Vlastimil Babka
2016-09-22 14:08       ` Michal Hocko
2016-09-22 14:08         ` Michal Hocko
2016-09-22 14:52         ` Michal Hocko
2016-09-22 14:52           ` Michal Hocko
2016-09-22 14:59           ` Vlastimil Babka
2016-09-22 14:59             ` Vlastimil Babka
2016-09-22 15:06           ` Vlastimil Babka
2016-09-22 15:06             ` Vlastimil Babka
2016-09-23  4:04             ` Hillf Danton
2016-09-23  4:04               ` Hillf Danton
2016-09-23  6:55               ` Vlastimil Babka
2016-09-23  6:55                 ` Vlastimil Babka
2016-09-23  8:23                 ` Michal Hocko
2016-09-23  8:23                   ` Michal Hocko
2016-09-23 10:47                   ` Vlastimil Babka
2016-09-23 10:47                     ` Vlastimil Babka
2016-09-23 12:06                     ` Michal Hocko
2016-09-23 12:06                       ` Michal Hocko
2016-09-06 13:52 ` [PATCH 3/4] mm, compaction: restrict full priority to non-costly orders Vlastimil Babka
2016-09-06 13:52   ` Vlastimil Babka
2016-09-21 17:15   ` Michal Hocko
2016-09-21 17:15     ` Michal Hocko
2016-09-06 13:52 ` [PATCH 4/4] mm, compaction: make full priority ignore pageblock suitability Vlastimil Babka
2016-09-06 13:52   ` Vlastimil Babka
2016-09-15 18:51 ` [PATCH 0/4] reintroduce compaction feedback for OOM decisions Arkadiusz Miskiewicz
2016-09-15 18:51   ` Arkadiusz Miskiewicz
2016-09-21 17:18 ` Michal Hocko
2016-09-21 17:18   ` Michal Hocko
2016-09-22 15:18   ` Vlastimil Babka
2016-09-22 15:18     ` Vlastimil Babka
2016-09-23  8:26     ` Michal Hocko
2016-09-23  8:26       ` Michal Hocko
2016-09-23 10:55       ` Vlastimil Babka
2016-09-23 10:55         ` Vlastimil Babka
2016-09-23 12:09         ` Michal Hocko
2016-09-23 12:09           ` 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=20160906135258.18335-3-vbabka@suse.cz \
    --to=vbabka@suse.cz \
    --cc=Ralf-Peter.Rohbeck@quantum.com \
    --cc=a.miskiewicz@gmail.com \
    --cc=akpm@linux-foundation.org \
    --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 2/4] mm, compaction: more reliably increase direct compaction priority' \
    /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.