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Date:   Mon, 18 Feb 2019 14:43:35 +0100
From:   Greg Kroah-Hartman <>
Cc:     Greg Kroah-Hartman <>,, Dave Chinner <>,
        Wolfgang Walter <>, Roman Gushchin <>,
        Spock <>, Rik van Riel <>,
        Michal Hocko <>,
        Andrew Morton <>,
        Linus Torvalds <>
Subject: [PATCH 4.19 69/85] Revert "mm: slowly shrink slabs with a relatively small number of objects"

4.19-stable review patch.  If anyone has any objections, please let me know.


From: Dave Chinner <>

commit a9a238e83fbb0df31c3b9b67003f8f9d1d1b6c96 upstream.

This reverts commit 172b06c32b9497 ("mm: slowly shrink slabs with a
relatively small number of objects").

This change changes the agressiveness of shrinker reclaim, causing small
cache and low priority reclaim to greatly increase scanning pressure on
small caches.  As a result, light memory pressure has a disproportionate
affect on small caches, and causes large caches to be reclaimed much
faster than previously.

As a result, it greatly perturbs the delicate balance of the VFS caches
(dentry/inode vs file page cache) such that the inode/dentry caches are
reclaimed much, much faster than the page cache and this drives us into
several other caching imbalance related problems.

As such, this is a bad change and needs to be reverted.

[ Needs some massaging to retain the later seekless shrinker

Fixes: 172b06c32b9497 ("mm: slowly shrink slabs with a relatively small number of objects")
Signed-off-by: Dave Chinner <>
Cc: Wolfgang Walter <>
Cc: Roman Gushchin <>
Cc: Spock <>
Cc: Rik van Riel <>
Cc: Michal Hocko <>
Cc: <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Greg Kroah-Hartman <>

 mm/vmscan.c |   10 ----------
 1 file changed, 10 deletions(-)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -477,16 +477,6 @@ static unsigned long do_shrink_slab(stru
 	delta *= 4;
 	do_div(delta, shrinker->seeks);
-	/*
-	 * Make sure we apply some minimal pressure on default priority
-	 * even on small cgroups. Stale objects are not only consuming memory
-	 * by themselves, but can also hold a reference to a dying cgroup,
-	 * preventing it from being reclaimed. A dying cgroup with all
-	 * corresponding structures like per-cpu stats and kmem caches
-	 * can be really big, so it may lead to a significant waste of memory.
-	 */
-	delta = max_t(unsigned long long, delta, min(freeable, batch_size));
 	total_scan += delta;
 	if (total_scan < 0) {
 		pr_err("shrink_slab: %pF negative objects to delete nr=%ld\n",

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