From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 EAC8438C411 for ; Thu, 12 Mar 2026 04:07:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773288439; cv=none; b=jiJq0r5eKxj/hVo9rdvrZI9c4feyAxD58HMnAw+5IiQABfwA7BPpUSzB2K04zDYZ3YrFMGXrXO8iq11iroxNk8D/MbtDjLXN+EPo2M2DIracXEQhXfIDm38+KKpzGGojL6cBgQfCE6UupWtQuZBvGOsTA5k86H9HZ7WXW13YejE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773288439; c=relaxed/simple; bh=RWQN9osrrSrfXBsLl2N0XmsfkGHU0HkShvlQVPmW4+U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MxYpesM0iXJHevwpD4cTkOXym7Vbt050aDRBPX592vfVkQ4BQTlruanVozYV4e34d1pCJdUmtZFV/IK7aj+1sEU1xDzbPhKrzVxO8U46paEK6Nub3q1Hr6q4cezEmoQd+FQRDYOIMtxZo2oCqyXT22b6pNdO0tiVE9qoaucpxBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=YDTw9NSp; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YDTw9NSp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773288437; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/+1K6U2HNH5Jf/hAFVeExQ4SDvY1teH+hVqb1jlKGzs=; b=YDTw9NSpyljwTnC98JIHVvhy7HpweFP+fOPpam1Zm1GjF8sRS/MHjLuRqRhr722gXjU5w1 nEUOuIXx0czS15Bry0Tg25PQdo7nNB4xvHICcwD1Lk29VmrmwrRXwvEkeKELdBFY7wEGlN AnehvdAI2HSZhBW6JJ2ZcOgydNDvlAQ= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-668-u6ygS8FqOzGplCIXW1Kc_Q-1; Thu, 12 Mar 2026 00:07:11 -0400 X-MC-Unique: u6ygS8FqOzGplCIXW1Kc_Q-1 X-Mimecast-MFC-AGG-ID: u6ygS8FqOzGplCIXW1Kc_Q_1773288429 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5C883195608A; Thu, 12 Mar 2026 04:07:09 +0000 (UTC) Received: from fedora-laptop-x1.redhat.com (unknown [10.72.112.57]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E2EA219560A6; Thu, 12 Mar 2026 04:07:03 +0000 (UTC) From: Li Wang To: mkoutny@suse.com, yosryahmed@google.com Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Michal Hocko , Muchun Song , Nhat Pham , Tejun Heo , Roman Gushchin , Shakeel Butt Subject: [PATCH v2 6/7] selftests/cgroup: replace hardcoded page size values in test_zswap Date: Thu, 12 Mar 2026 12:06:26 +0800 Message-ID: <20260312040627.55257-6-liwang@redhat.com> In-Reply-To: <20260312040627.55257-1-liwang@redhat.com> References: <20260312040627.55257-1-liwang@redhat.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 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. Signed-off-by: Li Wang Cc: Johannes Weiner Cc: Michal Hocko Cc: Michal Koutný Cc: Muchun Song Cc: Nhat Pham Cc: Tejun Heo Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yosry Ahmed --- tools/testing/selftests/cgroup/test_zswap.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index 654874fb371b..4eb88930b45f 100644 --- a/tools/testing/selftests/cgroup/test_zswap.c +++ b/tools/testing/selftests/cgroup/test_zswap.c @@ -13,6 +13,8 @@ #include "kselftest.h" #include "cgroup_util.h" +static size_t pagesize; + static int read_int(const char *path, size_t *value) { FILE *file; @@ -68,11 +70,11 @@ static int allocate_and_read_bytes(const char *cgroup, void *arg) if (!mem) return -1; - for (int i = 0; i < size; i += 4095) + for (int i = 0; i < size; i += pagesize) 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 += pagesize) { if (mem[i] != 'a') ret = -1; } @@ -83,7 +85,6 @@ static int allocate_and_read_bytes(const char *cgroup, void *arg) static int allocate_bytes(const char *cgroup, void *arg) { - long pagesize = sysconf(_SC_PAGESIZE); size_t size = (size_t)arg; char *mem = (char *)malloc(size); @@ -263,7 +264,6 @@ static int test_zswapin(const char *root) */ static int attempt_writeback(const char *cgroup, void *arg) { - long pagesize = sysconf(_SC_PAGESIZE); size_t memsize = MB(4); char buf[pagesize]; long zswap_usage; @@ -416,7 +416,6 @@ static int test_zswap_writeback_disabled(const char *root) static int test_no_invasive_cgroup_shrink(const char *root) { int ret = KSFT_FAIL; - long pagesize = sysconf(_SC_PAGESIZE); size_t control_allocation_size = MB(64); char *control_allocation = NULL, *wb_group = NULL, *control_group = NULL; @@ -479,7 +478,7 @@ static int no_kmem_bypass_child(const char *cgroup, void *arg) 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 += pagesize) ((char *)allocation)[i] = 'a'; values->child_allocated = true; pause(); @@ -527,7 +526,7 @@ static int test_no_kmem_bypass(const char *root) 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 / pagesize; trigger_allocation_size = sys_info.totalram / 20; /* Set up test memcg */ @@ -554,7 +553,7 @@ static int test_no_kmem_bypass(const char *root) if (!trigger_allocation) break; - for (int i = 0; i < trigger_allocation_size; i += 4095) + for (int i = 0; i < trigger_allocation_size; i += pagesize) trigger_allocation[i] = 'b'; usleep(100000); free(trigger_allocation); @@ -565,8 +564,8 @@ static int test_no_kmem_bypass(const char *root) /* 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 * pagesize - zswapped; + int result_ok = delta < stored_pages * pagesize / 4; ret = result_ok ? KSFT_PASS : KSFT_FAIL; break; @@ -622,6 +621,7 @@ int main(int argc, char **argv) char root[PATH_MAX]; int i, state; + pagesize = sysconf(_SC_PAGESIZE); ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); if (cg_find_unified_root(root, sizeof(root), NULL)) -- 2.53.0