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 B9AC4362133 for ; Fri, 24 Apr 2026 10:06:29 +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=1777025189; cv=none; b=B5EBAdQ7IiPP7EYuQSv0tXSDnn88RYDyHygvFN7nRmgg6lRFbGy1kiACJeuGzM0r7BYzTLBj9UCzGYZ7mPDfmo3SNJ0jUtVDTyiuXhv9dPaolzH2XCMkNo84RMZH5hXRmdzyYmaZ5e2UIUDzTSik09u2/vpWTAOcDdjsvdjwX8o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777025189; c=relaxed/simple; bh=r0o6LUz0xG0ZnrNVXGukgy1hCB9fHgtfWhCWve45sVA=; h=Date:To:From:Subject:Message-Id; b=ob0q9Rdt+ehFMek62eA577ZPE0IP4xXE2uPsMx21lXjH175OflnlljesWw/5v96nIH7ExVFr9tZOHV23vlDbCHl9XT9C8jYucj6Ad5mT2e3bvkFW5vQdpuiNfs7p7nuDCr6CSKF2IqJ3pRTt6cbcPHvdA85zsJv3tM3RWYSQL2I= 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=cUJ2k4Co; 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="cUJ2k4Co" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58FEFC19425; Fri, 24 Apr 2026 10:06:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777025189; bh=r0o6LUz0xG0ZnrNVXGukgy1hCB9fHgtfWhCWve45sVA=; h=Date:To:From:Subject:From; b=cUJ2k4CoTIPDkIJw2/02F/dgalBhFAoWetbfO5WocmC5hEMPRr/Uz3gvAkRMo5fXq UXAAxDsTqQvhhM2JnnfL+8mGgXEBqUIUT4qvZhJ7nyraj/I1yfJE6amVPfnzpnQpYy eWhI12wmFeFG8RjloB0/PRw7VWYFM3eufWETMY0Q= Date: Fri, 24 Apr 2026 03:06:28 -0700 To: mm-commits@vger.kernel.org,li.wang@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-cgroup-replace-hardcoded-page-size-values-in-test_zswap.patch added to mm-new branch Message-Id: <20260424100629.58FEFC19425@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: replace hardcoded page size values in test_zswap has been added to the -mm mm-new branch. Its filename is selftests-cgroup-replace-hardcoded-page-size-values-in-test_zswap.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-cgroup-replace-hardcoded-page-size-values-in-test_zswap.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: replace hardcoded page size values in test_zswap Date: Fri, 24 Apr 2026 12:00:56 +0800 test_zswap uses hardcoded values of 4095 and 4096 throughout as page stride and page size, which are only correct on systems with a 4K page size. On architectures with larger pages (e.g., 64K on arm64 or ppc64), these constants cause memory to be touched at sub-page granularity, leading to inefficient access patterns and incorrect page count calculations, which can cause test failures. Replace all hardcoded 4095 and 4096 values with a global pagesize variable initialized from sysconf(_SC_PAGESIZE) at startup, and remove the redundant local sysconf() calls scattered across individual functions. No functional change on 4K page size systems. Link: https://lore.kernel.org/20260424040059.12940-6-li.wang@linux.dev Signed-off-by: Li Wang Acked-by: Yosry Ahmed Reviewed-by: Jiayuan Chen Cc: Johannes Weiner Cc: Michal Hocko Cc: Michal Koutný Cc: Muchun Song Cc: Tejun Heo Cc: Roman Gushchin Cc: Shakeel Butt Cc: Chengming Zhou Cc: Nhat Pham Cc: Waiman Long Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- tools/testing/selftests/cgroup/test_zswap.c | 45 ++++++++++-------- 1 file changed, 25 insertions(+), 20 deletions(-) --- a/tools/testing/selftests/cgroup/test_zswap.c~selftests-cgroup-replace-hardcoded-page-size-values-in-test_zswap +++ a/tools/testing/selftests/cgroup/test_zswap.c @@ -15,6 +15,8 @@ #include "kselftest.h" #include "cgroup_util.h" +static int page_size; + #define PATH_ZSWAP "/sys/module/zswap" #define PATH_ZSWAP_ENABLED "/sys/module/zswap/parameters/enabled" @@ -73,11 +75,11 @@ static int allocate_and_read_bytes(const if (!mem) return -1; - for (int i = 0; i < size; i += 4095) + for (int i = 0; i < size; i += page_size) mem[i] = 'a'; /* Go through the allocated memory to (z)swap in and out pages */ - for (int i = 0; i < size; i += 4095) { + for (int i = 0; i < size; i += page_size) { if (mem[i] != 'a') ret = -1; } @@ -93,7 +95,7 @@ static int allocate_bytes(const char *cg if (!mem) return -1; - for (int i = 0; i < size; i += 4095) + for (int i = 0; i < size; i += page_size) mem[i] = 'a'; free(mem); return 0; @@ -167,7 +169,7 @@ static int test_swapin_nozswap(const cha int ret = KSFT_FAIL; char *test_group, mem_max_buf[32]; long swap_peak, zswpout, min_swap; - size_t allocation_size = sysconf(_SC_PAGESIZE) * 512; + size_t allocation_size = page_size * 512; min_swap = allocation_size / 4; snprintf(mem_max_buf, sizeof(mem_max_buf), "%zu", allocation_size * 3/4); @@ -245,7 +247,7 @@ static int test_zswapin(const char *root goto out; } - if (zswpin < MB(24) / sysconf(_SC_PAGESIZE)) { + if (zswpin < MB(24) / page_size) { ksft_print_msg("at least 24MB should be brought back from zswap\n"); goto out; } @@ -272,9 +274,8 @@ out: */ static int attempt_writeback(const char *cgroup, void *arg) { - long pagesize = sysconf(_SC_PAGESIZE); size_t memsize = MB(4); - char buf[pagesize]; + char buf[page_size]; long zswap_usage; bool wb_enabled = *(bool *) arg; int ret = -1; @@ -289,11 +290,11 @@ static int attempt_writeback(const char * half empty, this will result in data that is still compressible * and ends up in zswap, with material zswap usage. */ - for (int i = 0; i < pagesize; i++) - buf[i] = i < pagesize/2 ? (char) i : 0; + for (int i = 0; i < page_size; i++) + buf[i] = i < page_size/2 ? (char) i : 0; - for (int i = 0; i < memsize; i += pagesize) - memcpy(&mem[i], buf, pagesize); + for (int i = 0; i < memsize; i += page_size) + memcpy(&mem[i], buf, page_size); /* Try and reclaim allocated memory */ if (cg_write_numeric(cgroup, "memory.reclaim", memsize)) { @@ -304,8 +305,8 @@ static int attempt_writeback(const char zswap_usage = cg_read_long(cgroup, "memory.zswap.current"); /* zswpin */ - for (int i = 0; i < memsize; i += pagesize) { - if (memcmp(&mem[i], buf, pagesize)) { + for (int i = 0; i < memsize; i += page_size) { + if (memcmp(&mem[i], buf, page_size)) { ksft_print_msg("invalid memory\n"); goto out; } @@ -441,7 +442,7 @@ static int test_no_invasive_cgroup_shrin if (cg_enter_current(control_group)) goto out; control_allocation = malloc(control_allocation_size); - for (int i = 0; i < control_allocation_size; i += 4095) + for (int i = 0; i < control_allocation_size; i += page_size) control_allocation[i] = 'a'; if (cg_read_key_long(control_group, "memory.stat", "zswapped") < 1) goto out; @@ -481,7 +482,7 @@ static int no_kmem_bypass_child(const ch values->child_allocated = true; return -1; } - for (long i = 0; i < values->target_alloc_bytes; i += 4095) + for (long i = 0; i < values->target_alloc_bytes; i += page_size) ((char *)allocation)[i] = 'a'; values->child_allocated = true; pause(); @@ -529,7 +530,7 @@ static int test_no_kmem_bypass(const cha min_free_kb_low = sys_info.totalram / 500000; values->target_alloc_bytes = (sys_info.totalram - min_free_kb_high * 1000) + sys_info.totalram * 5 / 100; - stored_pages_threshold = sys_info.totalram / 5 / 4096; + stored_pages_threshold = sys_info.totalram / 5 / page_size; trigger_allocation_size = sys_info.totalram / 20; /* Set up test memcg */ @@ -556,7 +557,7 @@ static int test_no_kmem_bypass(const cha if (!trigger_allocation) break; - for (int i = 0; i < trigger_allocation_size; i += 4095) + for (int i = 0; i < trigger_allocation_size; i += page_size) trigger_allocation[i] = 'b'; usleep(100000); free(trigger_allocation); @@ -567,8 +568,8 @@ static int test_no_kmem_bypass(const cha /* 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 "); - int delta = stored_pages * 4096 - zswapped; - int result_ok = delta < stored_pages * 4096 / 4; + int delta = stored_pages * page_size - zswapped; + int result_ok = delta < stored_pages * page_size / 4; ret = result_ok ? KSFT_PASS : KSFT_FAIL; break; @@ -622,7 +623,7 @@ static int allocate_random_and_wait(cons close(fd); /* Touch all pages to ensure they're faulted in */ - for (size_t i = 0; i < size; i += PAGE_SIZE) + for (size_t i = 0; i < size; i += page_size) mem[i] = mem[i]; /* Use MADV_PAGEOUT to push pages into zswap */ @@ -752,6 +753,10 @@ int main(int argc, char **argv) char root[PATH_MAX]; int i; + page_size = sysconf(_SC_PAGE_SIZE); + if (page_size <= 0) + page_size = BUF_SIZE; + ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); if (cg_find_unified_root(root, sizeof(root), NULL)) _ 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