test_swapin_nozswap can hit OOM before reaching its assertions on some
setups. The test currently sets memory.max=8M and then allocates/reads
32M with memory.zswap.max=0, which may over-constrain reclaim and kill
the workload process.
Raise memory.max to 24M so the workload can make forward progress, and
lower the swap_peak expectation from 24M to 8M to keep the check robust
across environments.
The test intent is unchanged: verify that swapping happens while zswap
remains unused when memory.zswap.max=0.
=== Error Logs ===
# ./test_zswap
TAP version 13
1..7
ok 1 test_zswap_usage
not ok 2 test_swapin_nozswap
...
# dmesg
[271641.879153] test_zswap invoked oom-killer: gfp_mask=0xcc0(GFP_KERNEL),
order=0, oom_score_adj=0
[271641.879168] CPU: 1 UID: 0 PID: 177372 Comm: test_zswap Kdump: loaded Not
tainted 6.12.0-211.el10.ppc64le #1 VOLUNTARY
[271641.879171] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202
0xf000005 of:IBM,FW940.02 (UL940_041) hv:phyp pSeries
[271641.879173] Call Trace:
[271641.879174] [c00000037540f730] [c00000000127ec44]
dump_stack_lvl+0x88/0xc4 (unreliable)
[271641.879184] [c00000037540f760] [c0000000005cc594] dump_header+0x5c/0x1e4
[271641.879188] [c00000037540f7e0] [c0000000005cb464]
oom_kill_process+0x324/0x3b0
[271641.879192] [c00000037540f860] [c0000000005cbe48]
out_of_memory+0x118/0x420
[271641.879196] [c00000037540f8f0] [c00000000070d8ec]
mem_cgroup_out_of_memory+0x18c/0x1b0
[271641.879200] [c00000037540f990] [c000000000713888]
try_charge_memcg+0x598/0x890
[271641.879204] [c00000037540fa70] [c000000000713dbc] charge_memcg+0x5c/0x110
[271641.879207] [c00000037540faa0] [c0000000007159f8]
__mem_cgroup_charge+0x48/0x120
[271641.879211] [c00000037540fae0] [c000000000641914]
alloc_anon_folio+0x2b4/0x5a0
[271641.879215] [c00000037540fb60] [c000000000641d58]
do_anonymous_page+0x158/0x6b0
[271641.879218] [c00000037540fbd0] [c000000000642f8c]
__handle_mm_fault+0x4bc/0x910
[271641.879221] [c00000037540fcf0] [c000000000643500]
handle_mm_fault+0x120/0x3c0
[271641.879224] [c00000037540fd40] [c00000000014bba0]
___do_page_fault+0x1c0/0x980
[271641.879228] [c00000037540fdf0] [c00000000014c44c]
hash__do_page_fault+0x2c/0xc0
[271641.879232] [c00000037540fe20] [c0000000001565d8]
do_hash_fault+0x128/0x1d0
[271641.879236] [c00000037540fe50] [c000000000008be0]
data_access_common_virt+0x210/0x220
[271641.879548] Tasks state (memory values in pages):
...
[271641.879550] [ pid ] uid tgid total_vm rss rss_anon rss_file
rss_shmem pgtables_bytes swapents oom_score_adj name
[271641.879555] [ 177372] 0 177372 571 0 0 0
0 51200 96 0 test_zswap
[271641.879562]
oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/no_zswap_test,task_memcg=/no_zswap_test,task=test_zswap,pid=177372,uid=0
[271641.879578] Memory cgroup out of memory: Killed process 177372
(test_zswap) total-vm:36544kB, anon-rss:0kB, file-rss:0kB, shmem-rss:0kB, UID:0
pgtables:50kB oom_score_adj:0
Signed-off-by: Li Wang <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Michal Koutný <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Yosry Ahmed <[email protected]>
---
tools/testing/selftests/cgroup/test_zswap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/cgroup/test_zswap.c
b/tools/testing/selftests/cgroup/test_zswap.c
index ec64daaa2f5a..8bf5fc34bb23 100644
--- a/tools/testing/selftests/cgroup/test_zswap.c
+++ b/tools/testing/selftests/cgroup/test_zswap.c
@@ -168,7 +168,7 @@ static int test_swapin_nozswap(const char *root)
goto out;
if (cg_create(test_group))
goto out;
- if (cg_write(test_group, "memory.max", "8M"))
+ if (cg_write(test_group, "memory.max", "24M"))
goto out;
if (cg_write(test_group, "memory.zswap.max", "0"))
goto out;
@@ -184,8 +184,8 @@ static int test_swapin_nozswap(const char *root)
goto out;
}
- if (swap_peak < MB(24)) {
- ksft_print_msg("at least 24MB of memory should be swapped
out\n");
+ if (swap_peak < MB(8)) {
+ ksft_print_msg("at least 8MB of memory should be swapped
out\n");
goto out;
}
--
2.53.0
