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From: Vladimir Davydov <vdavydov@parallels.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	devel@openvz.org, Mel Gorman <mgorman@suse.de>,
	Michal Hocko <mhocko@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Rik van Riel <riel@redhat.com>,
	Dave Chinner <dchinner@redhat.com>,
	Glauber Costa <glommer@gmail.com>
Subject: [PATCH 1/3] mm: vmscan: shrink_slab: rename max_pass -> freeable
Date: Fri, 17 Jan 2014 23:25:29 +0400	[thread overview]
Message-ID: <4e2efebe688e06574f6495c634ac45d799e1518d.1389982079.git.vdavydov@parallels.com> (raw)

The name `max_pass' is misleading, because this variable actually keeps
the estimate number of freeable objects, not the maximal number of
objects we can scan in this pass, which can be twice that. Rename it to
reflect its actual meaning.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Glauber Costa <glommer@gmail.com>
---
 mm/vmscan.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index eea668d..31aa997 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -224,15 +224,15 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	unsigned long freed = 0;
 	unsigned long long delta;
 	long total_scan;
-	long max_pass;
+	long freeable;
 	long nr;
 	long new_nr;
 	int nid = shrinkctl->nid;
 	long batch_size = shrinker->batch ? shrinker->batch
 					  : SHRINK_BATCH;
 
-	max_pass = shrinker->count_objects(shrinker, shrinkctl);
-	if (max_pass == 0)
+	freeable = shrinker->count_objects(shrinker, shrinkctl);
+	if (freeable == 0)
 		return 0;
 
 	/*
@@ -244,14 +244,14 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 
 	total_scan = nr;
 	delta = (4 * nr_pages_scanned) / shrinker->seeks;
-	delta *= max_pass;
+	delta *= freeable;
 	do_div(delta, lru_pages + 1);
 	total_scan += delta;
 	if (total_scan < 0) {
 		printk(KERN_ERR
 		"shrink_slab: %pF negative objects to delete nr=%ld\n",
 		       shrinker->scan_objects, total_scan);
-		total_scan = max_pass;
+		total_scan = freeable;
 	}
 
 	/*
@@ -260,26 +260,26 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	 * shrinkers to return -1 all the time. This results in a large
 	 * nr being built up so when a shrink that can do some work
 	 * comes along it empties the entire cache due to nr >>>
-	 * max_pass.  This is bad for sustaining a working set in
+	 * freeable. This is bad for sustaining a working set in
 	 * memory.
 	 *
 	 * Hence only allow the shrinker to scan the entire cache when
 	 * a large delta change is calculated directly.
 	 */
-	if (delta < max_pass / 4)
-		total_scan = min(total_scan, max_pass / 2);
+	if (delta < freeable / 4)
+		total_scan = min(total_scan, freeable / 2);
 
 	/*
 	 * Avoid risking looping forever due to too large nr value:
 	 * never try to free more than twice the estimate number of
 	 * freeable entries.
 	 */
-	if (total_scan > max_pass * 2)
-		total_scan = max_pass * 2;
+	if (total_scan > freeable * 2)
+		total_scan = freeable * 2;
 
 	trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
 				nr_pages_scanned, lru_pages,
-				max_pass, delta, total_scan);
+				freeable, delta, total_scan);
 
 	while (total_scan >= batch_size) {
 		unsigned long ret;
-- 
1.7.10.4

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             reply	other threads:[~2014-01-17 19:25 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-17 19:25 Vladimir Davydov [this message]
2014-01-17 19:25 ` [PATCH 2/3] mm: vmscan: get rid of DEFAULT_SEEKS and document shrink_slab logic Vladimir Davydov
2014-02-04 21:58   ` Andrew Morton
2014-02-05  7:16     ` Vladimir Davydov
2014-02-05 20:52       ` Andrew Morton
2014-02-06 18:51         ` Vladimir Davydov
2014-01-17 19:25 ` [PATCH 3/3] mm: vmscan: shrink_slab: do not skip caches with < batch_size objects Vladimir Davydov
2014-01-21 22:22 ` [PATCH 1/3] mm: vmscan: shrink_slab: rename max_pass -> freeable David Rientjes
2014-01-22  6:11   ` Vladimir Davydov

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