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Revert "mm: slowly shrink slabs with a relatively small number of objects"

PATCH In review Sasha Levin 1 participant 2 messages Oct 26, 2018 – Oct 31, 2018

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Sasha Levin

author maintainer
#0 lore raw

PATCH 1/1 Revert "mm: slowly shrink slabs with a relatively small number of objects"

This reverts commit 62aad93f09c1952ede86405894df1b22012fd5ab.

Which was upstream commit 172b06c32b94 ("mm: slowly shrink slabs with a relatively small number of objects").

The upstream commit was found to cause regressions. While there is a proposed fix upstream, revent this patch from stable trees for now as testing the fix will take some time.

Signed-off-by Sasha Levin <[email protected]>
---
 mm/vmscan.c | 11 -----------
 1 file changed, 11 deletions(-)
mm/vmscan.c +0 -11
index fc0436407471..03822f86f288 100644
@@ -386,17 +386,6 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
 	delta = freeable >> priority;
 	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",
Signature · 1 line
2.17.1
author maintainer
#1 lore raw
Quoted 26 lines · Sasha Levin

This reverts commit 62aad93f09c1952ede86405894df1b22012fd5ab.

Which was upstream commit 172b06c32b94 ("mm: slowly shrink slabs with a relatively small number of objects").

The upstream commit was found to cause regressions. While there is a proposed fix upstream, revent this patch from stable trees for now as testing the fix will take some time.

Signed-off-by Sasha Levin <[email protected]>

---
mm/vmscan.c | 11 -----------

1 file changed, 11 deletions(-)
mm/vmscan.c +0 -4
index fc0436407471..03822f86f288 100644
@@ -386,17 +386,6 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
 	delta = freeable >> priority;
 	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

mm/vmscan.c static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, · line 391

Quoted 10 lines
mm/vmscan.c +0 -7
-	 * 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",

I've queued it up for 4.18.

--
Thanks,
Sasha