From nobody Fri Apr 3 01:22:48 2026 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 6AE022F5321 for ; Thu, 2 Apr 2026 06:38:23 +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=1775111904; cv=none; b=tp3kGsaKVoiJjioMeAbSBWFhmc8CTkZxvQAtwHc7CpKMG8fAlOyGH+4zti5uPqjc/NAWoyWRgrVDg912bbXRRu3WMCard+J/pSGGp7o/oPOJ/+En6VyVdBrdBjsw/4gw147vFS2a+k1oFou9kBCt6GeNcAQZnVl/DojVzl0OOUI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775111904; c=relaxed/simple; bh=XpHm9KLm5d4is10F2JA3aMc55B5rzmcmdvlRIDJbX1M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Vqbc8yCxDyBvOr3Z2uuAkZiYcFsDm+Rt22ax+xt8as2nOw+jnZLvbWBf9p+vdo6lgBg0XdMVGwBXUYVzLfcaaHc001xDXT1dhHx2V8rEYF8MdfDB1tD49OFPARvqFytbu6+sa6RsPn0wwKpFsw1bFqw13jBXkwYnoZ6Hl4/ZcE0= 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=XIY4KF77; 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="XIY4KF77" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775111902; 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=LSR6JP1MlIyPdrrVRarFMh7ouoNO5yIpt67p9cGm3mU=; b=XIY4KF77kuM+TK4Kpf8Fjse6zqdDV4IaD2f06YXrrmy7ro3kSt+eeHQg6oM68k8kEa1VLM NRUoorty6ioNZS51BPv78mNJXm/ywD5MpEPfqOAComKEr3DsAKWjHI/l318aMX4RNgzfYZ 1UVe2qC0mM+bAC1CT1uWYl6tTxVfl4Q= 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-282-Hl_RMtkzOY2MBUzmdjZPgw-1; Thu, 02 Apr 2026 02:38:18 -0400 X-MC-Unique: Hl_RMtkzOY2MBUzmdjZPgw-1 X-Mimecast-MFC-AGG-ID: Hl_RMtkzOY2MBUzmdjZPgw_1775111895 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 694FC1800365; Thu, 2 Apr 2026 06:38:15 +0000 (UTC) Received: from fedora-laptop-x1.redhat.com (unknown [10.72.112.158]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B2A691800351; Thu, 2 Apr 2026 06:38:06 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, rppt@kernel.org, david@kernel.org, hannes@cmpxchg.org, yosry@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, mhocko@suse.com, shuah@kernel.org, chengming.zhou@linux.dev, longman@redhat.com, nphamcs@gmail.com Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Michal Hocko , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Muchun Song , Tejun Heo , Roman Gushchin , Shakeel Butt Subject: [PATCH v6 5/8] selftests/cgroup: replace hardcoded page size values in test_zswap Date: Thu, 2 Apr 2026 14:37:11 +0800 Message-ID: <20260402063714.55124-6-liwang@redhat.com> In-Reply-To: <20260402063714.55124-1-liwang@redhat.com> References: <20260402063714.55124-1-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 3.4.1 on 10.30.177.111 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 Acked-by: Yosry Ahmed --- Notes: v6: - Use page_size replace the sysconf(_SC_PAGE_SIZE). v5: - Change pagesize by the global page_size. v1-4: - No changes. tools/testing/selftests/cgroup/test_zswap.c | 43 ++++++++++++--------- 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/se= lftests/cgroup/test_zswap.c index 516da5d52bfd..db4889bef6d4 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 int page_size; + #define PATH_ZSWAP "/sys/module/zswap" #define PATH_ZSWAP_ENABLED "/sys/module/zswap/parameters/enabled" =20 @@ -71,11 +73,11 @@ 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 page_size) 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 page_size) { if (mem[i] !=3D 'a') ret =3D -1; } @@ -91,7 +93,7 @@ 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 page_size) mem[i] =3D 'a'; free(mem); return 0; @@ -165,7 +167,7 @@ static int test_swapin_nozswap(const char *root) int ret =3D KSFT_FAIL; char *test_group, mem_max_buf[32]; long swap_peak, zswpout, min_swap; - size_t allocation_size =3D sysconf(_SC_PAGESIZE) * 512; + size_t allocation_size =3D page_size * 512; =20 min_swap =3D allocation_size / 4; snprintf(mem_max_buf, sizeof(mem_max_buf), "%zu", allocation_size * 3/4); @@ -243,7 +245,7 @@ static int test_zswapin(const char *root) goto out; } =20 - 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; } @@ -270,9 +272,8 @@ 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]; + char buf[page_size]; long zswap_usage; bool wb_enabled =3D *(bool *) arg; int ret =3D -1; @@ -287,11 +288,11 @@ static int attempt_writeback(const char *cgroup, void= *arg) * half empty, this will result in data that is still compressible * and ends up in zswap, with material zswap usage. */ - for (int i =3D 0; i < pagesize; i++) - buf[i] =3D i < pagesize/2 ? (char) i : 0; + for (int i =3D 0; i < page_size; i++) + buf[i] =3D i < page_size/2 ? (char) i : 0; =20 - for (int i =3D 0; i < memsize; i +=3D pagesize) - memcpy(&mem[i], buf, pagesize); + for (int i =3D 0; i < memsize; i +=3D page_size) + memcpy(&mem[i], buf, page_size); =20 /* Try and reclaim allocated memory */ if (cg_write_numeric(cgroup, "memory.reclaim", memsize)) { @@ -302,8 +303,8 @@ static int attempt_writeback(const char *cgroup, void *= arg) zswap_usage =3D cg_read_long(cgroup, "memory.zswap.current"); =20 /* zswpin */ - for (int i =3D 0; i < memsize; i +=3D pagesize) { - if (memcmp(&mem[i], buf, pagesize)) { + for (int i =3D 0; i < memsize; i +=3D page_size) { + if (memcmp(&mem[i], buf, page_size)) { ksft_print_msg("invalid memory\n"); goto out; } @@ -439,7 +440,7 @@ 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 page_size) control_allocation[i] =3D 'a'; if (cg_read_key_long(control_group, "memory.stat", "zswapped") < 1) goto out; @@ -479,7 +480,7 @@ 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 page_size) ((char *)allocation)[i] =3D 'a'; values->child_allocated =3D true; pause(); @@ -527,7 +528,7 @@ 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 / page_size; trigger_allocation_size =3D sys_info.totalram / 20; =20 /* Set up test memcg */ @@ -554,7 +555,7 @@ 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 page_size) trigger_allocation[i] =3D 'b'; usleep(100000); free(trigger_allocation); @@ -565,8 +566,8 @@ 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 * page_size - zswapped; + int result_ok =3D delta < stored_pages * page_size / 4; =20 ret =3D result_ok ? KSFT_PASS : KSFT_FAIL; break; @@ -616,6 +617,10 @@ int main(int argc, char **argv) char root[PATH_MAX]; int i; =20 + page_size =3D sysconf(_SC_PAGE_SIZE); + if (page_size <=3D 0) + page_size =3D BUF_SIZE; + ksft_print_header(); ksft_set_plan(ARRAY_SIZE(tests)); if (cg_find_unified_root(root, sizeof(root), NULL)) --=20 2.53.0