The patch titled
Subject: selftests: cgroup: add a selftest for memory.reclaim
has been added to the -mm tree. Its filename is
selftests-cgroup-add-a-selftest-for-memoryreclaim.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/selftests-cgroup-add-a-selftest-for-memoryreclaim.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/selftests-cgroup-add-a-selftest-for-memoryreclaim.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: selftests: cgroup: add a selftest for memory.reclaim
Add a new test for memory.reclaim that verifies that the interface
correctly reclaims memory as intended, from both anon and file pages.
Link: https://lkml.kernel.org/r/20220421234426.3494842-5-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Chen Wandun <chenwandun@xxxxxxxxxx>
Cc: Dan Schatzberg <schatzberg.dan@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: "Michal Koutný" <mkoutny@xxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Cc: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/cgroup/test_memcontrol.c | 86 +++++++++++++
1 file changed, 86 insertions(+)
--- a/tools/testing/selftests/cgroup/test_memcontrol.c~selftests-cgroup-add-a-selftest-for-memoryreclaim
+++ a/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -771,6 +771,91 @@ cleanup:
return ret;
}
+/*
+ * This test checks that memory.reclaim reclaims the given
+ * amount of memory (from both anon and file).
+ */
+static int test_memcg_reclaim(const char *root)
+{
+ int ret = KSFT_FAIL, fd, retries;
+ char *memcg;
+ long current, to_reclaim;
+ char buf[64];
+
+ memcg = cg_name(root, "memcg_test");
+ if (!memcg)
+ goto cleanup;
+
+ if (cg_create(memcg))
+ goto cleanup;
+
+ current = cg_read_long(memcg, "memory.current");
+ if (current != 0)
+ goto cleanup;
+
+ cg_run_nowait(memcg, alloc_anon_noexit, (void *) MB(50));
+ sleep(1);
+
+ fd = get_temp_fd();
+ if (fd < 0)
+ goto cleanup;
+
+ cg_run_nowait(memcg, alloc_pagecache_50M_noexit, (void *)(long)fd);
+ sleep(1);
+
+ current = cg_read_long(memcg, "memory.current");
+ if (!values_close(current, MB(100), 10))
+ goto cleanup;
+
+ /*
+ * Reclaim until current reaches 30M, make sure to reclaim over 50M to
+ * hit both anon and file.
+ */
+ retries = 5;
+ while (true) {
+ int err;
+
+ current = cg_read_long(memcg, "memory.current");
+ to_reclaim = current - MB(30);
+
+ /*
+ * We only keep looping if we get EAGAIN, which means we could
+ * not reclaim the full amount.
+ */
+ if (to_reclaim <= 0)
+ goto cleanup;
+
+
+ snprintf(buf, sizeof(buf), "%ld", to_reclaim);
+ err = cg_write(memcg, "memory.reclaim", buf);
+ if (!err) {
+ /*
+ * If writing succeeds, then the written amount should have been
+ * fully reclaimed (and maybe more).
+ */
+ current = cg_read_long(memcg, "memory.current");
+ if (!values_close(current, MB(30), 3) && current > MB(30))
+ goto cleanup;
+ break;
+ }
+
+ /* The kernel could not reclaim the full amount, try again. */
+ if (err == -EAGAIN && retries--)
+ continue;
+
+ /* We got an unexpected error or ran out of retries. */
+ goto cleanup;
+ }
+
+ ret = KSFT_PASS;
+cleanup:
+ cg_destroy(memcg);
+ free(memcg);
+ close(fd);
+
+ return ret;
+}
+
static int alloc_anon_50M_check_swap(const char *cgroup, void *arg)
{
long mem_max = (long)arg;
@@ -1281,6 +1366,7 @@ struct memcg_test {
T(test_memcg_high),
T(test_memcg_high_sync),
T(test_memcg_max),
+ T(test_memcg_reclaim),
T(test_memcg_oom_events),
T(test_memcg_swap_max),
T(test_memcg_sock),
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
selftests-cgroup-return-errno-from-cg_read-cg_write-on-failure.patch
selftests-cgroup-fix-alloc_anon_noexit-instantly-freeing-memory.patch
selftests-cgroup-add-a-selftest-for-memoryreclaim.patch
