From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 647B33624CE for ; Fri, 24 Apr 2026 10:06:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777025196; cv=none; b=o31+2HWzpU8ME2TMGqYB3p5HB+/0wZ64rY8yDHuDiqk2D+7dbjmVj9plibM2ndvfUKyV0VvahYHvzrstmBRcG6m1bNXbI1hXCqMAC9wBd7AQXcIz9qfPQOXVI3KsyiIP6jvNNW/zp2e8X5PM63PumQEja0hlSc7qSip6HB4deLA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777025196; c=relaxed/simple; bh=go1/Aoba+PUcmij9feCw5CXACVsWzoc/Mh/LzzISIKk=; h=Date:To:From:Subject:Message-Id; b=PRfcKdBkOXF5PRRANDx38NbdWO2F6ruRO+hWPSPb5ThNoiFwglRh17LlwhD5xgS0x5cTUUmkGBbdZnbK1m94+RZnkufnr6W9blb4vKwmakH+Uv23UAsjJ6lXXFtRTk7z+RVF7QTWC4A37nMG8LlbMLs86nFvVNMl+jkfo+S0Znk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=SIVTxfX6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SIVTxfX6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBBFFC19425; Fri, 24 Apr 2026 10:06:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777025196; bh=go1/Aoba+PUcmij9feCw5CXACVsWzoc/Mh/LzzISIKk=; h=Date:To:From:Subject:From; b=SIVTxfX694eNtLXD40lRXyJhy0T7QHxRBgBFCxKThO9IqQHjZEScQKCVSWMbzpgIQ Iahm9hfoa2UCVWoKXtNot2+DRQpCd4IGWbvNJ+f7GEPJkqiyCEA3vNq/XvuDzImo6O q1MgeMeyae8M9xPYOGaksGc+THolqPDIN0Vxc4a4= Date: Fri, 24 Apr 2026 03:06:35 -0700 To: mm-commits@vger.kernel.org,li.wang@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-cgroup-test_zswap-wait-for-asynchronous-writeback.patch added to mm-new branch Message-Id: <20260424100635.EBBFFC19425@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/cgroup: test_zswap: wait for asynchronous writeback has been added to the -mm mm-new branch. Its filename is selftests-cgroup-test_zswap-wait-for-asynchronous-writeback.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-cgroup-test_zswap-wait-for-asynchronous-writeback.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Li Wang Subject: selftests/cgroup: test_zswap: wait for asynchronous writeback Date: Fri, 24 Apr 2026 12:00:59 +0800 zswap writeback is asynchronous, but test_zswap.c checks writeback counters immediately after reclaim/trigger paths. On some platforms (e.g. ppc64le), this can race with background writeback and cause spurious failures even when behavior is correct. Add wait_for_writeback() to poll get_cg_wb_count() with a bounded timeout, and use it in: test_zswap_writeback_one() when writeback is expected test_no_invasive_cgroup_shrink() for the wb_group check This keeps the original before/after assertion style while making the tests robust against writeback completion latency. No test behavior change, selftest stability improvement only. Link: https://lore.kernel.org/20260424040059.12940-9-li.wang@linux.dev Signed-off-by: Li Wang Acked-by: Nhat Pham Cc: Johannes Weiner Cc: Michal Hocko Cc: Michal Koutný Cc: Muchun Song Cc: Tejun Heo Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yosry Ahmed Cc: Chengming Zhou Cc: Jiayuan Chen Cc: Waiman Long Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- tools/testing/selftests/cgroup/test_zswap.c | 28 ++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/cgroup/test_zswap.c~selftests-cgroup-test_zswap-wait-for-asynchronous-writeback +++ a/tools/testing/selftests/cgroup/test_zswap.c @@ -121,6 +121,27 @@ fail: } /* + * Writeback is asynchronous; poll until at least one writeback has + * been recorded for @cg, or until @timeout_ms has elapsed. + */ +static long wait_for_writeback(const char *cg, int timeout_ms) +{ + long elapsed, count; + for (elapsed = 0; elapsed < timeout_ms; elapsed += 100) { + count = get_cg_wb_count(cg); + + if (count < 0) + return -1; + if (count > 0) + return count; + + usleep(100000); + } + + return 0; +} + +/* * Sanity test to check that pages are written into zswap. */ static int test_zswap_usage(const char *root) @@ -345,7 +366,10 @@ static int test_zswap_writeback_one(cons return -1; /* Verify that zswap writeback occurred only if writeback was enabled */ - zswpwb_after = get_cg_wb_count(cgroup); + if (wb) + zswpwb_after = wait_for_writeback(cgroup, 5000); + else + zswpwb_after = get_cg_wb_count(cgroup); if (zswpwb_after < 0) return -1; @@ -476,7 +500,7 @@ static int test_no_invasive_cgroup_shrin } /* Verify that only zswapped memory from gwb_group has been written back */ - if (get_cg_wb_count(wb_group) > 0 && get_cg_wb_count(zw_group) == 0) + if (wait_for_writeback(wb_group, 5000) > 0 && get_cg_wb_count(zw_group) == 0) ret = KSFT_PASS; out: cg_enter_current(root); _ Patches currently in -mm which might be from li.wang@linux.dev are maintainers-update-li-wangs-email-address.patch selftests-cgroup-skip-test_zswap-if-zswap-is-globally-disabled.patch selftests-cgroup-avoid-oom-in-test_swapin_nozswap.patch selftests-cgroup-use-runtime-page-size-for-zswpin-check.patch selftests-cgroup-rename-page_size-to-buf_size-in-cgroup_util.patch selftests-cgroup-replace-hardcoded-page-size-values-in-test_zswap.patch selftest-cgroup-fix-zswap-test_no_invasive_cgroup_shrink-on-large-pagesize-system.patch selftest-cgroup-fix-zswap-attempt_writeback-on-64k-pagesize-system.patch selftests-cgroup-test_zswap-wait-for-asynchronous-writeback.patch