From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 13C492848A0 for ; Fri, 13 Mar 2026 04:36:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773376578; cv=none; b=asuvYxm/w4L9PWEELwAgNnM5jwB8O3HBXahnpSxc9rMNeiNtWTQ4r9Xk+3kKDplZ8WwcFPncor/wPzUcCaYfURG45LzPPwS1SLsH7mi0SPVXUeFqwXcQfQaFPL/qWOOBSQVmCFL341m0Pg1WxXtl66XuV7An0ufiwvUm9TTcuJ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773376578; c=relaxed/simple; bh=rVznYwTqH+UUEpFF7Mvt5jgLzDASwy3PyLejef9/CvQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=PKcE4uHwjDd+lN9XLpjbddAK+nO4FJH1GJ+aTjbn+ibxrP3quiVd4tRUqEKBgk/OvPJMVFW+93KUp0WWBPTr0wGluC5AcEtZauHez/V8nSpzDV5+Vo0/x9GysD/p7ISZheELq4cA76e+zUAKREHqSqaSHrUSOxbcFszn8rQlkEM= 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=EyzjHjt6; arc=none smtp.client-ip=170.10.129.124 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="EyzjHjt6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773376576; 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=AgscDGb8pb9Gegot485nSUiYl/sLdOaPVgxH0ipJXH4=; b=EyzjHjt6j3CVx/p45wgq3pu3OqGcTFFnRRO61Nr1s59XgSzF4kvbfVr+KSOkIOIXqZTf8D fregzlNKT3OyThZFElbVpd84sImi5+80lRB8LNWwLox/weHw6AkXCfP45ifMy4Zi4ktTk0 pcYBJdvp79rALasuPfiRyXSemFB4YHI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-671-GHm8LYEsONOwyAalF4RPoQ-1; Fri, 13 Mar 2026 00:36:11 -0400 X-MC-Unique: GHm8LYEsONOwyAalF4RPoQ-1 X-Mimecast-MFC-AGG-ID: GHm8LYEsONOwyAalF4RPoQ_1773376569 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1C19F18005BD; Fri, 13 Mar 2026 04:36:09 +0000 (UTC) Received: from fedora-laptop-x1.redhat.com (unknown [10.72.112.18]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ADF2319540C2; Fri, 13 Mar 2026 04:36:03 +0000 (UTC) From: Li Wang To: yosryahmed@google.com, nphamcs@gmail.com Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Michal Hocko , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Muchun Song , Tejun Heo , Roman Gushchin , Shakeel Butt Subject: [PATCH v3 5/7] selftests/cgroup: replace hardcoded page size values in test_zswap Date: Fri, 13 Mar 2026 12:35:30 +0800 Message-ID: <20260313043532.103987-5-liwang@redhat.com> In-Reply-To: <20260313043532.103987-1-liwang@redhat.com> References: <20260313043532.103987-1-liwang@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@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 10.30.177.17 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 | 22 +++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index 74b57331cbf1..cf5b1531c827 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; } @@ -88,7 +90,7 @@ static int allocate_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'; free(mem); return 0; @@ -267,7 +269,6 @@ 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; @@ -436,7 +437,7 @@ static int test_no_invasive_cgroup_shrink(const char *root) 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 += pagesize) control_allocation[i] = 'a'; if (cg_read_key_long(control_group, "memory.stat", "zswapped") < 1) goto out; @@ -476,7 +477,7 @@ 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(); @@ -524,7 +525,7 @@ 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 */ @@ -551,7 +552,7 @@ 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); @@ -562,8 +563,8 @@ 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; @@ -616,6 +617,7 @@ int main(int argc, char **argv) char root[PATH_MAX]; int i; + 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