| Message ID | 20230912083800.57435-1-cerasuolodomenico@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | selftests: cgroup: fix test_zswap error path and meaningless check | expand |
On Tue, 12 Sep 2023 10:38:00 +0200 Domenico Cerasuolo <cerasuolodomenico@gmail.com> wrote: > Replace destruction paths with simple returns before the test cgroup is > created, there is nothing to free or destroy at that point. > > Remove pointless check, stored_pages is a size_t and cannot be < 0. > > ... > > @@ -208,8 +208,6 @@ static int test_no_kmem_bypass(const char *root) > free(trigger_allocation); > if (get_zswap_stored_pages(&stored_pages)) > break; > - if (stored_pages < 0) > - break; > /* If memory was pushed to zswap, verify it belongs to memcg */ > if (stored_pages > stored_pages_threshold) { > int zswapped = cg_read_key_long(test_group, "memory.stat", "zswapped "); stored_pages will be set to -1 on error. It would be better to cast stored_pages to ssize_t in the check, rather than simply ignoring errors?
On Tue, Sep 12, 2023 at 7:18 PM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Tue, 12 Sep 2023 10:38:00 +0200 Domenico Cerasuolo <cerasuolodomenico@gmail.com> wrote: > > > Replace destruction paths with simple returns before the test cgroup is > > created, there is nothing to free or destroy at that point. > > > > Remove pointless check, stored_pages is a size_t and cannot be < 0. > > > > ... > > > > @@ -208,8 +208,6 @@ static int test_no_kmem_bypass(const char *root) > > free(trigger_allocation); > > if (get_zswap_stored_pages(&stored_pages)) > > break; > > - if (stored_pages < 0) > > - break; > > /* If memory was pushed to zswap, verify it belongs to memcg */ > > if (stored_pages > stored_pages_threshold) { > > int zswapped = cg_read_key_long(test_group, "memory.stat", "zswapped "); > > stored_pages will be set to -1 on error. It would be better to cast > stored_pages to ssize_t in the check, rather than simply ignoring > errors? I'm not sure I understood, isn't it safe to just rely on the return value of get_zswap_stored_pages a few lines above? In that case we break the loop and the value of stored_pages is not used.
diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index 49def87a909b..5257106776d5 100644 --- a/tools/testing/selftests/cgroup/test_zswap.c +++ b/tools/testing/selftests/cgroup/test_zswap.c @@ -178,10 +178,10 @@ static int test_no_kmem_bypass(const char *root) /* Set up test memcg */ if (cg_write(root, "cgroup.subtree_control", "+memory")) - goto out; + return KSFT_FAIL; test_group = cg_name(root, "kmem_bypass_test"); if (!test_group) - goto out; + return KSFT_FAIL; /* Spawn memcg child and wait for it to allocate */ set_min_free_kb(min_free_kb_low); @@ -208,8 +208,6 @@ static int test_no_kmem_bypass(const char *root) free(trigger_allocation); if (get_zswap_stored_pages(&stored_pages)) break; - if (stored_pages < 0) - break; /* If memory was pushed to zswap, verify it belongs to memcg */ if (stored_pages > stored_pages_threshold) { int zswapped = cg_read_key_long(test_group, "memory.stat", "zswapped ");
Replace destruction paths with simple returns before the test cgroup is created, there is nothing to free or destroy at that point. Remove pointless check, stored_pages is a size_t and cannot be < 0. Fixes: a549f9f31561 ("selftests: cgroup: add test_zswap with no kmem bypass test") Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> --- tools/testing/selftests/cgroup/test_zswap.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)