The patch titled
Subject: selftests: cgroup: update per-memcg zswap writeback selftest
has been added to the -mm mm-unstable branch. Its filename is
selftests-cgroup-update-per-memcg-zswap-writeback-selftest.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-cgroup-update-per-memcg-zswap-writeback-selftest.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Subject: selftests: cgroup: update per-memcg zswap writeback selftest
Date: Mon, 27 Nov 2023 15:45:59 -0800
The memcg-zswap self test is updated to adjust to the behavior change
implemented by commit 87730b165089 ("zswap: make shrinking memcg-aware"),
where zswap performs writeback for specific memcg.
Link: https://lkml.kernel.org/r/20231127234600.2971029-6-nphamcs@xxxxxxxxx
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/cgroup/test_zswap.c | 74 ++++++++++++------
1 file changed, 50 insertions(+), 24 deletions(-)
--- a/tools/testing/selftests/cgroup/test_zswap.c~selftests-cgroup-update-per-memcg-zswap-writeback-selftest
+++ a/tools/testing/selftests/cgroup/test_zswap.c
@@ -50,9 +50,9 @@ static int get_zswap_stored_pages(size_t
return read_int("/sys/kernel/debug/zswap/stored_pages", value);
}
-static int get_zswap_written_back_pages(size_t *value)
+static int get_cg_wb_count(const char *cg)
{
- return read_int("/sys/kernel/debug/zswap/written_back_pages", value);
+ return cg_read_key_long(cg, "memory.stat", "zswp_wb");
}
static long get_zswpout(const char *cgroup)
@@ -73,6 +73,24 @@ static int allocate_bytes(const char *cg
return 0;
}
+static char *setup_test_group_1M(const char *root, const char *name)
+{
+ char *group_name = cg_name(root, name);
+
+ if (!group_name)
+ return NULL;
+ if (cg_create(group_name))
+ goto fail;
+ if (cg_write(group_name, "memory.max", "1M")) {
+ cg_destroy(group_name);
+ goto fail;
+ }
+ return group_name;
+fail:
+ free(group_name);
+ return NULL;
+}
+
/*
* Sanity test to check that pages are written into zswap.
*/
@@ -117,43 +135,51 @@ out:
/*
* When trying to store a memcg page in zswap, if the memcg hits its memory
- * limit in zswap, writeback should not be triggered.
- *
- * This was fixed with commit 0bdf0efa180a("zswap: do not shrink if cgroup may
- * not zswap"). Needs to be revised when a per memcg writeback mechanism is
- * implemented.
+ * limit in zswap, writeback should affect only the zswapped pages of that
+ * memcg.
*/
static int test_no_invasive_cgroup_shrink(const char *root)
{
- size_t written_back_before, written_back_after;
int ret = KSFT_FAIL;
- char *test_group;
+ size_t control_allocation_size = MB(10);
+ char *control_allocation, *wb_group = NULL, *control_group = NULL;
/* Set up */
- test_group = cg_name(root, "no_shrink_test");
- if (!test_group)
+ wb_group = setup_test_group_1M(root, "per_memcg_wb_test1");
+ if (!wb_group)
+ return KSFT_FAIL;
+ if (cg_write(wb_group, "memory.zswap.max", "10K"))
goto out;
- if (cg_create(test_group))
- goto out;
- if (cg_write(test_group, "memory.max", "1M"))
+ control_group = setup_test_group_1M(root, "per_memcg_wb_test2");
+ if (!control_group)
goto out;
- if (cg_write(test_group, "memory.zswap.max", "10K"))
+
+ /* Push some test_group2 memory into zswap */
+ if (cg_enter_current(control_group))
goto out;
- if (get_zswap_written_back_pages(&written_back_before))
+ control_allocation = malloc(control_allocation_size);
+ for (int i = 0; i < control_allocation_size; i += 4095)
+ control_allocation[i] = 'a';
+ if (cg_read_key_long(control_group, "memory.stat", "zswapped") < 1)
goto out;
- /* Allocate 10x memory.max to push memory into zswap */
- if (cg_run(test_group, allocate_bytes, (void *)MB(10)))
+ /* Allocate 10x memory.max to push wb_group memory into zswap and trigger wb */
+ if (cg_run(wb_group, allocate_bytes, (void *)MB(10)))
goto out;
- /* Verify that no writeback happened because of the memcg allocation */
- if (get_zswap_written_back_pages(&written_back_after))
- goto out;
- if (written_back_after == written_back_before)
+ /* Verify that only zswapped memory from gwb_group has been written back */
+ if (get_cg_wb_count(wb_group) > 0 && get_cg_wb_count(control_group) == 0)
ret = KSFT_PASS;
out:
- cg_destroy(test_group);
- free(test_group);
+ cg_enter_current(root);
+ if (control_group) {
+ cg_destroy(control_group);
+ free(control_group);
+ }
+ cg_destroy(wb_group);
+ free(wb_group);
+ if (control_allocation)
+ free(control_allocation);
return ret;
}
_
Patches currently in -mm which might be from cerasuolodomenico@xxxxxxxxx are
zswap-make-shrinking-memcg-aware.patch
mm-memcg-add-per-memcg-zswap-writeback-stat.patch
selftests-cgroup-update-per-memcg-zswap-writeback-selftest.patch
