The patch titled
Subject: cgroup: account for memory_recursiveprot in test_memcg_low()
has been added to the -mm tree. Its filename is
cgroup-account-for-memory_recursiveprot-in-test_memcg_low.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/cgroup-account-for-memory_recursiveprot-in-test_memcg_low.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/cgroup-account-for-memory_recursiveprot-in-test_memcg_low.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: David Vernet <void@xxxxxxxxxxxxx>
Subject: cgroup: account for memory_recursiveprot in test_memcg_low()
The test_memcg_low() testcase in test_memcontrol.c verifies the expected
behavior of groups using the memory.low knob. Part of the testcase
verifies that a group with memory.low that experiences reclaim due to
memory pressure elsewhere in the system, observes memory.events.low events
as a result of that reclaim.
In commit 8a931f801340 ("mm: memcontrol: recursive memory.low
protection"), the memory controller was updated to propagate memory.low
and memory.min protection from a parent group to its children via a
configurable memory_recursiveprot mount option. This unfortunately broke
the memcg tests, which asserts that a sibling that experienced reclaim but
had a memory.low value of 0, would not observe any memory.low events.
This patch updates test_memcg_low() to account for the new behavior
introduced by memory_recursiveprot.
So as to make the test resilient to multiple configurations, the patch
also adds a new proc_mount_contains() helper that checks for a string in
/proc/mounts, and is used to toggle behavior based on whether the default
memory_recursiveprot was present.
Link: https://lkml.kernel.org/r/20220423155619.3669555-3-void@xxxxxxxxxxxxx
Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/cgroup/cgroup_util.c | 12 +++++++++
tools/testing/selftests/cgroup/cgroup_util.h | 1
tools/testing/selftests/cgroup/test_memcontrol.c | 16 ++++++++++---
3 files changed, 26 insertions(+), 3 deletions(-)
--- a/tools/testing/selftests/cgroup/cgroup_util.c~cgroup-account-for-memory_recursiveprot-in-test_memcg_low
+++ a/tools/testing/selftests/cgroup/cgroup_util.c
@@ -528,6 +528,18 @@ int set_oom_adj_score(int pid, int score
return 0;
}
+int proc_mount_contains(const char *option)
+{
+ char buf[4 * PAGE_SIZE];
+ ssize_t read;
+
+ read = read_text("/proc/mounts", buf, sizeof(buf));
+ if (read < 0)
+ return read;
+
+ return strstr(buf, option) != NULL;
+}
+
ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
{
char path[PATH_MAX];
--- a/tools/testing/selftests/cgroup/cgroup_util.h~cgroup-account-for-memory_recursiveprot-in-test_memcg_low
+++ a/tools/testing/selftests/cgroup/cgroup_util.h
@@ -48,6 +48,7 @@ extern int is_swap_enabled(void);
extern int set_oom_adj_score(int pid, int score);
extern int cg_wait_for_proc_count(const char *cgroup, int count);
extern int cg_killall(const char *cgroup);
+int proc_mount_contains(const char *option);
extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size);
extern int proc_read_strstr(int pid, bool thread, const char *item, const char *needle);
extern pid_t clone_into_cgroup(int cgroup_fd);
--- a/tools/testing/selftests/cgroup/test_memcontrol.c~cgroup-account-for-memory_recursiveprot-in-test_memcg_low
+++ a/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -21,6 +21,8 @@
#include "../kselftest.h"
#include "cgroup_util.h"
+static bool has_recursiveprot;
+
/*
* This test creates two nested cgroups with and without enabling
* the memory controller.
@@ -525,15 +527,18 @@ static int test_memcg_low(const char *ro
}
for (i = 0; i < ARRAY_SIZE(children); i++) {
+ int no_low_events_index = has_recursiveprot ? 2 : 1;
+
oom = cg_read_key_long(children[i], "memory.events", "oom ");
low = cg_read_key_long(children[i], "memory.events", "low ");
if (oom)
goto cleanup;
- if (i < 2 && low <= 0)
+ if (i <= no_low_events_index && low <= 0)
goto cleanup;
- if (i >= 2 && low)
+ if (i > no_low_events_index && low)
goto cleanup;
+
}
ret = KSFT_PASS;
@@ -1362,7 +1367,7 @@ struct memcg_test {
int main(int argc, char **argv)
{
char root[PATH_MAX];
- int i, ret = EXIT_SUCCESS;
+ int i, proc_status, ret = EXIT_SUCCESS;
if (cg_find_unified_root(root, sizeof(root)))
ksft_exit_skip("cgroup v2 isn't mounted\n");
@@ -1378,6 +1383,11 @@ int main(int argc, char **argv)
if (cg_write(root, "cgroup.subtree_control", "+memory"))
ksft_exit_skip("Failed to set memory controller\n");
+ proc_status = proc_mount_contains("memory_recursiveprot");
+ if (proc_status < 0)
+ ksft_exit_skip("Failed to query cgroup mount option\n");
+ has_recursiveprot = proc_status;
+
for (i = 0; i < ARRAY_SIZE(tests); i++) {
switch (tests[i].fn(root)) {
case KSFT_PASS:
_
Patches currently in -mm which might be from void@xxxxxxxxxxxxx are
cgroups-refactor-children-cgroups-in-memcg-tests.patch
cgroup-account-for-memory_recursiveprot-in-test_memcg_low.patch
cgroup-account-for-memory_localevents-in-test_memcg_oom_group_leaf_events.patch
cgroup-removing-racy-check-in-test_memcg_sock.patch
cgroup-fix-racy-check-in-alloc_pagecache_max_30m-helper-function.patch
