From nobody Mon Apr 6 09:11:36 2026 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 1193E36C0CF for ; Sun, 22 Mar 2026 06:11:33 +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=1774159896; cv=none; b=DU3XNlxKlytPKXAwGO/xgqaU//J/jOxLQVSHZ2SMM8p75yCAzPePD4cB9kuQFUcic9Vh5OX+AsRFYX2snsunsLz0q/9mKsyPtNJkx64iiSak6OpADxctW+srfU9FGnHLlRmKV+sXjaG099IDNzklvpvoHk7pLhlDJYCGEyLkVhg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774159896; c=relaxed/simple; bh=/5SJMslpwqE9AZtD6jAcInepSkwSg68CiVm9j3igxho=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UpTLCmiSAxTKz+5a32ZPx5UEWNidMr7cA3owdQWIV8FcAXb8oxY12lfWxCrpx/V3U5P6wOf5jijmFtGquQYpizeh7nSnP42GEcDOhmZ2g2mjNAFMDpFsxS7UgEEp3uuQrvy5xR+sb9CuS9qNyogw1ARSd+8uE4YMR2O99YC/BM8= 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=Ny3dtbRV; 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="Ny3dtbRV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774159893; 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=7dCjpbk9shfMvsTLeYWdQuK6o2QNz7TDr6M6Z2XEj8E=; b=Ny3dtbRVfSBNN7h4nOF6XgVUxsf8may+vP/MnSxWnAccDhGlFtJjrjgJ4d2jLckp6Xhqlj VwXAsdKIYdWU8RwIsIcIoqUGjXChvyNUtppPNF4HXtsachUoUV8EbQmAEezETMv/K+9LZv Pd5yGi7Sebalu80aRqspGR2/jTdM94Q= Received: from mx-prod-mc-08.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-507-U2Bm-i80O8m2tIqlio_K8Q-1; Sun, 22 Mar 2026 02:11:28 -0400 X-MC-Unique: U2Bm-i80O8m2tIqlio_K8Q-1 X-Mimecast-MFC-AGG-ID: U2Bm-i80O8m2tIqlio_K8Q_1774159886 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7694E1800345; Sun, 22 Mar 2026 06:11:26 +0000 (UTC) Received: from fedora-laptop-x1.redhat.com (unknown [10.72.112.34]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4B19C1955F21; Sun, 22 Mar 2026 06:11:19 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, yosry@kernel.org, yosryahmed@google.com, nphamcs@gmail.com, hannes@cmpxchg.org, mhocko@kernel.org, mkoutny@suse.com, muchun.song@linux.dev, tj@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev Cc: longman@redhat.com, liwang@redhat.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v4 5/7] selftests/cgroup: replace hardcoded page size values in test_zswap Date: Sun, 22 Mar 2026 14:10:36 +0800 Message-ID: <20260322061038.156146-6-liwang@redhat.com> In-Reply-To: <20260322061038.156146-1-liwang@redhat.com> References: <20260322061038.156146-1-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: quoted-printable 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 Koutn=C3=BD Cc: Muchun Song Cc: Nhat Pham Cc: Tejun Heo Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yosry Ahmed Acked-by: 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/se= lftests/cgroup/test_zswap.c index 4982e8c4759c..407cfb6ae34d 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" =20 +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) =20 if (!mem) return -1; - for (int i =3D 0; i < size; i +=3D 4095) + for (int i =3D 0; i < size; i +=3D pagesize) mem[i] =3D 'a'; =20 /* Go through the allocated memory to (z)swap in and out pages */ - for (int i =3D 0; i < size; i +=3D 4095) { + for (int i =3D 0; i < size; i +=3D pagesize) { if (mem[i] !=3D 'a') ret =3D -1; } @@ -88,7 +90,7 @@ static int allocate_bytes(const char *cgroup, void *arg) =20 if (!mem) return -1; - for (int i =3D 0; i < size; i +=3D 4095) + for (int i =3D 0; i < size; i +=3D pagesize) mem[i] =3D '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 =3D sysconf(_SC_PAGESIZE); size_t memsize =3D MB(4); char buf[pagesize]; long zswap_usage; @@ -436,7 +437,7 @@ static int test_no_invasive_cgroup_shrink(const char *r= oot) if (cg_enter_current(control_group)) goto out; control_allocation =3D malloc(control_allocation_size); - for (int i =3D 0; i < control_allocation_size; i +=3D 4095) + for (int i =3D 0; i < control_allocation_size; i +=3D pagesize) control_allocation[i] =3D '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, voi= d *arg) values->child_allocated =3D true; return -1; } - for (long i =3D 0; i < values->target_alloc_bytes; i +=3D 4095) + for (long i =3D 0; i < values->target_alloc_bytes; i +=3D pagesize) ((char *)allocation)[i] =3D 'a'; values->child_allocated =3D true; pause(); @@ -524,7 +525,7 @@ static int test_no_kmem_bypass(const char *root) min_free_kb_low =3D sys_info.totalram / 500000; values->target_alloc_bytes =3D (sys_info.totalram - min_free_kb_high * 10= 00) + sys_info.totalram * 5 / 100; - stored_pages_threshold =3D sys_info.totalram / 5 / 4096; + stored_pages_threshold =3D sys_info.totalram / 5 / pagesize; trigger_allocation_size =3D sys_info.totalram / 20; =20 /* Set up test memcg */ @@ -551,7 +552,7 @@ static int test_no_kmem_bypass(const char *root) =20 if (!trigger_allocation) break; - for (int i =3D 0; i < trigger_allocation_size; i +=3D 4095) + for (int i =3D 0; i < trigger_allocation_size; i +=3D pagesize) trigger_allocation[i] =3D '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 =3D cg_read_key_long(test_group, "memory.stat", "zswapped = "); - int delta =3D stored_pages * 4096 - zswapped; - int result_ok =3D delta < stored_pages * 4096 / 4; + int delta =3D stored_pages * pagesize - zswapped; + int result_ok =3D delta < stored_pages * pagesize / 4; =20 ret =3D result_ok ? KSFT_PASS : KSFT_FAIL; break; @@ -616,6 +617,7 @@ int main(int argc, char **argv) char root[PATH_MAX]; int i; =20 + pagesize =3D sysconf(_SC_PAGESIZE); ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); if (cg_find_unified_root(root, sizeof(root), NULL)) --=20 2.53.0