selftests-cgroup-include-slab-in-test_percpu_basic-memory-check.patch removed from -mm tree

The quilt patch titled
Subject: selftests/cgroup: include slab in test_percpu_basic memory check
has been removed from the -mm tree. Its filename was
selftests-cgroup-include-slab-in-test_percpu_basic-memory-check.patch

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

------------------------------------------------------
From: Li Wang <[email protected]>
Subject: selftests/cgroup: include slab in test_percpu_basic memory check
Date: Fri, 1 May 2026 10:20:58 +0800

test_percpu_basic() currently compares memory.current against only memory.stat:percpu after creating 1000 child cgroups.

Observed failure:
#./test_kmem
ok 1 test_kmem_basic
ok 2 test_kmem_memcg_deletion
ok 3 test_kmem_proc_kpagecgroup
ok 4 test_kmem_kernel_stacks
ok 5 test_kmem_dead_cgroups
memory.current 11530240
percpu 8440000
not ok 6 test_percpu_basic

That assumption is too strict: child cgroup creation also allocates slab-backed metadata, so memory.current is expected to be larger than percpu alone. One visible path is:

cgroup_mkdir()

    cgroup_create()
      cgroup_addrm_file()
        cgroup_add_file()
          __kernfs_create_file()
            __kernfs_new_node()
              kmem_cache_zalloc()

These kernfs allocations are charged as slab and show up in memory.stat:slab.

Update the check to compare memory.current against (percpu + slab) within MAX_VMSTAT_ERROR, and print slab/delta in the failure message to improve diagnostics.

---

 tools/testing/selftests/cgroup/test_kmem.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

@@ -353,7 +353,7 @@ static int test_percpu_basic(const char
 {
 	int ret = KSFT_FAIL;
 	char *parent, *child;
-	long current, percpu;
+	long current, percpu, slab;
 	int i;
 
 	parent = cg_name(root, "percpu_basic_test");

@@ -383,13 +383,14 @@ static int test_percpu_basic(const char
 
 	current = cg_read_long(parent, "memory.current");
 	percpu = cg_read_key_long(parent, "memory.stat", "percpu ");
+	slab = cg_read_key_long(parent, "memory.stat", "slab ");
 
-	if (current > 0 && percpu > 0 && labs(current - percpu) <
-	    MAX_VMSTAT_ERROR)
+	if (current > 0 && percpu > 0 && slab >= 0 &&
+			labs(current - (percpu + slab)) < MAX_VMSTAT_ERROR)
 		ret = KSFT_PASS;
 	else
-		printf("memory.current %ld\npercpu %ld\n",
-		       current, percpu);
+		printf("memory.current %ld\npercpu %ld\nslab %ld\ndelta %ld\n",
+			current, percpu, slab, current - (percpu + slab));
 
 cleanup_children:
 	for (i = 0; i < 1000; i++) {

_

Patches currently in -mm which might be from [email protected] are