[merged mm-hotfixes-stable] selftests-cgroup-fix-test_kmem_basic-false-positives.patch removed from -mm tree

[merged mm-hotfixes-stable] selftests-cgroup-fix-test_kmem_basic-false-positives.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: selftests: cgroup: fix test_kmem_basic false positives
has been removed from the -mm tree.  Its filename was
     selftests-cgroup-fix-test_kmem_basic-false-positives.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: selftests: cgroup: fix test_kmem_basic false positives
Date: Tue, 1 Aug 2023 09:56:32 -0400

This test fails routinely in our prod testing environment, and I can
reproduce it locally as well.

The test allocates dcache inside a cgroup, then drops the memory limit
and checks that usage drops correspondingly. The reason it fails is
because dentries are freed with an RCU delay - a debugging sleep shows
that usage drops as expected shortly after.

Insert a 1s sleep after dropping the limit. This should be good
enough, assuming that machines running those tests are otherwise not
very busy.

Link: https://lkml.kernel.org/r/20230801135632.1768830-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/cgroup/test_kmem.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/tools/testing/selftests/cgroup/test_kmem.c~selftests-cgroup-fix-test_kmem_basic-false-positives
+++ a/tools/testing/selftests/cgroup/test_kmem.c
@@ -70,6 +70,10 @@ static int test_kmem_basic(const char *r
 		goto cleanup;
 
 	cg_write(cg, "memory.high", "1M");
+
+	/* wait for RCU freeing */
+	sleep(1);
+
 	slab1 = cg_read_key_long(cg, "memory.stat", "slab ");
 	if (slab1 <= 0)
 		goto cleanup;
_

Patches currently in -mm which might be from hannes@cmpxchg.org are

mm-kill-frontswap.patch
mm-kill-frontswap-fix.patch
mm-zswap-use-zswap_invalidate_entry-for-duplicates.patch
mm-zswap-tighten-up-entry-invalidation.patch
mm-zswap-kill-zswap_get_swap_cache_page.patch