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

This reverts commit 62aad93f09.

Which was upstream commit 172b06c32b ("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 <sashal@kernel.org>

mm/vmscan.c

@@ -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",