This series fixes two test failures in test_zswap observed when running on a single-core VM (-smp 1) with 4GB of RAM.
Patch 1 addresses a race condition in test_zswap_writeback() where waitpid() returns before the exiting child process is switched away by the kernel, causing an immediate write of "+memory" to cgroup.subtree_control to fail with -EBUSY. We fix this by waiting for cgroup.events to report "populated 0". Patch 2 standardizes cgroup key-value stat and event parsers on 64-bit types by replacing cg_read_key_long() with cg_read_key_s64() across the entire cgroup selftest suite, avoiding 32-bit integer overflows on systems with large memory or high counter values. Patch 3 fixes an implicit unsigned conversion bug in test_no_kmem_bypass() where small negative timing differences between debugfs stored_pages and cgroup zswapped bytes caused the comparison to falsely fail due to unsigned promotion. v5 -> v6: - Now it is a 3-patch series. - Patch 1: wait for cgroup to unpopulate in test_zswap_writeback (unchanged, retains Michal's Acked-by). - Patch 2: convert cg_read_key_*() helpers to s64, define s64 as signed long long in cgroup_util.h, update poll/reporting helpers (values_close, values_close_report with llabs), helper functions, and all callers across cgroup selftests to avoid 32-bit overflow/truncation (suggested by Michal Koutný). - signed long long for s64 was based on powerpc/include/utils.h - Patch 3: test_zswap: fix implicit unsigned promotion bug in test_no_kmem_bypass, updated to use s64 for delta and max_delta. - Verify warning-free builds on both 64-bit and 32-bit (gcc -m32). v4 -> v5: - Patch 2: Introduce cg_read_key_long_long() to return a long long value, and have cg_read_key_long use it and convert to long. - Patch 2: Make zswapped a long long. This prevents an overflow on 32-bit platforms (Andrew Morton, Sashiko). v3 -> v4: - Patch 2: Use long long for delta and max_delta and explicitly cast stored_pages to avoid integer overflow and implicit unsigned promotion warnings on 32-bit platforms (Andrew Morton, Sashiko). v2 -> v3: - Patch 1: Collect Acked-by from Michal Koutný. - Patch 2: Explicitly cast stored_pages to (long) in delta calculation and inline the return comparison (Michal Koutný). v1 -> v2: - Patch 1: Replace EBUSY retry loop with cg_read_strcmp_wait() waiting for cgroup.events "populated 0" (Michal Koutný). - Patch 1: Clarify task lifecycle in commit description (Yosry Ahmed). - Patch 2: Remove abs() and declare delta/zswapped as signed longs with a signed threshold comparison (Michal Koutný). - Patch 2: Add Fixes tag (Michal Koutný). v5: https://lore.kernel.org/all/[email protected]/ v4: https://lore.kernel.org/all/[email protected]/ v3: https://lore.kernel.org/all/[email protected]/ v2: https://lore.kernel.org/all/[email protected]/ v1: https://lore.kernel.org/all/[email protected]/ Wilson Felipe Pereira (3): selftests/cgroup: test_zswap: wait for cgroup to unpopulate in test_zswap_writeback selftests/cgroup: convert cg_read_key_*() helpers to s64 selftests/cgroup: test_zswap: fix implicit unsigned promotion bug in test_no_kmem_bypass .../selftests/cgroup/lib/cgroup_util.c | 14 ++-- .../cgroup/lib/include/cgroup_util.h | 22 +++--- tools/testing/selftests/cgroup/test_cpu.c | 47 ++++++------- tools/testing/selftests/cgroup/test_freezer.c | 16 ++--- tools/testing/selftests/cgroup/test_kmem.c | 56 ++++++++------- .../selftests/cgroup/test_memcontrol.c | 69 ++++++++++--------- tools/testing/selftests/cgroup/test_pids.c | 5 +- tools/testing/selftests/cgroup/test_zswap.c | 63 +++++++++-------- 8 files changed, 154 insertions(+), 138 deletions(-) -- 2.55.0.979.g7e5102b832-goog
