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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 8a931f8013
("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@manifault.com
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
parent
f0cdaa5687
commit
cdc69458a5
3 changed files with 26 additions and 3 deletions
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@ -528,6 +528,18 @@ int set_oom_adj_score(int pid, int score)
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return 0;
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}
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int proc_mount_contains(const char *option)
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{
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char buf[4 * PAGE_SIZE];
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ssize_t read;
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read = read_text("/proc/mounts", buf, sizeof(buf));
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if (read < 0)
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return read;
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return strstr(buf, option) != NULL;
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}
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ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
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{
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char path[PATH_MAX];
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@ -48,6 +48,7 @@ extern int is_swap_enabled(void);
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extern int set_oom_adj_score(int pid, int score);
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extern int cg_wait_for_proc_count(const char *cgroup, int count);
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extern int cg_killall(const char *cgroup);
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int proc_mount_contains(const char *option);
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extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size);
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extern int proc_read_strstr(int pid, bool thread, const char *item, const char *needle);
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extern pid_t clone_into_cgroup(int cgroup_fd);
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@ -21,6 +21,8 @@
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#include "../kselftest.h"
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#include "cgroup_util.h"
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static bool has_recursiveprot;
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/*
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* This test creates two nested cgroups with and without enabling
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* the memory controller.
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@ -525,15 +527,18 @@ static int test_memcg_low(const char *root)
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}
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for (i = 0; i < ARRAY_SIZE(children); i++) {
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int no_low_events_index = has_recursiveprot ? 2 : 1;
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oom = cg_read_key_long(children[i], "memory.events", "oom ");
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low = cg_read_key_long(children[i], "memory.events", "low ");
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if (oom)
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goto cleanup;
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if (i < 2 && low <= 0)
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if (i <= no_low_events_index && low <= 0)
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goto cleanup;
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if (i >= 2 && low)
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if (i > no_low_events_index && low)
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goto cleanup;
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}
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ret = KSFT_PASS;
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@ -1382,7 +1387,7 @@ struct memcg_test {
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int main(int argc, char **argv)
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{
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char root[PATH_MAX];
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int i, ret = EXIT_SUCCESS;
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int i, proc_status, ret = EXIT_SUCCESS;
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if (cg_find_unified_root(root, sizeof(root)))
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ksft_exit_skip("cgroup v2 isn't mounted\n");
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@ -1398,6 +1403,11 @@ int main(int argc, char **argv)
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if (cg_write(root, "cgroup.subtree_control", "+memory"))
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ksft_exit_skip("Failed to set memory controller\n");
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proc_status = proc_mount_contains("memory_recursiveprot");
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if (proc_status < 0)
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ksft_exit_skip("Failed to query cgroup mount option\n");
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has_recursiveprot = proc_status;
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for (i = 0; i < ARRAY_SIZE(tests); i++) {
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switch (tests[i].fn(root)) {
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case KSFT_PASS:
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