From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD6A8109E546 for ; Thu, 26 Mar 2026 03:28:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 56CC76B00A2; Wed, 25 Mar 2026 23:28:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 544DD6B00A3; Wed, 25 Mar 2026 23:28:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 481FA6B00A4; Wed, 25 Mar 2026 23:28:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 382076B00A2 for ; Wed, 25 Mar 2026 23:28:14 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id E6B50BCAC5 for ; Thu, 26 Mar 2026 03:28:13 +0000 (UTC) X-FDA: 84586780866.09.1AAB3EC Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf14.hostedemail.com (Postfix) with ESMTP id 0BAEB100011 for ; Thu, 26 Mar 2026 03:28:11 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=SKmSXBNa; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf14.hostedemail.com: domain of liwang@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=liwang@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774495692; h=from:from:sender: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:dkim-signature; bh=z7qTVQy4P3P+tWAwnSkI8eaROMeV/uij3L4ybuXlnco=; b=4wKpIRruBy6Ry6ipT5Eit4Oe+TG34I74ekUkxocXydbv3Nq+0NzIttscsKnYnG86b3O9aG g0WxRqx7z+xLRQIkVQerlmFtpCZbPG1N0SkC6AaO5si6l7HORtzQg+6qsxCwcmn03rc1qZ GImPgKo/uE3867zIfu5SudWKoyqfYGI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774495692; a=rsa-sha256; cv=none; b=LU72+RgWnejYMaQiH5XczbMB5qqGk7spKF50MKbvvfToL2QCDUp0XoMonLTvnGeF47SHpy E9saMw+HusDXgU7bBhKyiU88jXJsecAE2MFjsxAiU8C9s/LzrCJ4rG0p94Rsqgg59Bl7/s 5/6aGWubFecgjWMb1QoZuF8gHPgetHo= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=SKmSXBNa; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf14.hostedemail.com: domain of liwang@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=liwang@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774495691; 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=z7qTVQy4P3P+tWAwnSkI8eaROMeV/uij3L4ybuXlnco=; b=SKmSXBNa5/DkiCkXywq3PEUE2tzKxsHPgWw9lZ0n49eX0g1ynCXwc4QNNA1O5DGPlKrkfm 88mg5vrGcrny1RRpz9+GM0+DDD+C87F3maj3vFdgE9zIBSQqErtEYEZdjJLxhxytLzSDIr vPdAfKspCbZCMtzLU44LNx2Py6w9Dsc= 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-390-g6BzXI2gPqOlcblx0mevOA-1; Wed, 25 Mar 2026 23:28:08 -0400 X-MC-Unique: g6BzXI2gPqOlcblx0mevOA-1 X-Mimecast-MFC-AGG-ID: g6BzXI2gPqOlcblx0mevOA_1774495685 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C8BD819560A7; Thu, 26 Mar 2026 03:28:05 +0000 (UTC) Received: from fedora-laptop-x1.redhat.com (unknown [10.72.112.83]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7C0731955D84; Thu, 26 Mar 2026 03:27:59 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, yosry@kernel.org, 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, Yosry Ahmed Subject: [PATCH v5 8/8] selftests/cgroup: test_zswap: wait for asynchronous writeback Date: Thu, 26 Mar 2026 11:26:58 +0800 Message-ID: <20260326032658.96819-9-liwang@redhat.com> In-Reply-To: <20260326032658.96819-1-liwang@redhat.com> References: <20260326032658.96819-1-liwang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-MFC-PROC-ID: xIE6gX7xlSfP3_epMpEwpKQfQczyMY92zlcxPp1fn0c_1774495685 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 0BAEB100011 X-Stat-Signature: 1hgk5uc5cjhcys4x4qu7ie4qqbupc9qe X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1774495691-360344 X-HE-Meta: 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 g7Zb5vvC 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: zswap writeback is asynchronous, but test_zswap.c checks writeback counters immediately after reclaim/trigger paths. On some platforms (e.g. ppc64le), this can race with background writeback and cause spurious failures even when behavior is correct. Add wait_for_writeback() to poll get_cg_wb_count() with a bounded timeout, and use it in: test_zswap_writeback_one() when writeback is expected test_no_invasive_cgroup_shrink() for the wb_group check This keeps the original before/after assertion style while making the tests robust against writeback completion latency. No test behavior change, selftest stability improvement only. 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 | 28 +++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_zswap.c b/tools/testing/selftests/cgroup/test_zswap.c index e96e316f7c47..e7d5dbc1ef7f 100644 --- a/tools/testing/selftests/cgroup/test_zswap.c +++ b/tools/testing/selftests/cgroup/test_zswap.c @@ -118,6 +118,27 @@ static char *setup_test_group_1M(const char *root, const char *name) return NULL; } +/* + * Writeback is asynchronous; poll until at least one writeback has + * been recorded for @cg, or until @timeout_ms has elapsed. + */ +static long wait_for_writeback(const char *cg, int timeout_ms) +{ + int elapsed, count; + for (elapsed = 0; elapsed < timeout_ms; elapsed += 100) { + count = get_cg_wb_count(cg); + + if (count < 0) + return -1; + if (count > 0) + return count; + + usleep(100000); + } + + return 0; +} + /* * Sanity test to check that pages are written into zswap. */ @@ -343,7 +364,10 @@ static int test_zswap_writeback_one(const char *cgroup, bool wb) return -1; /* Verify that zswap writeback occurred only if writeback was enabled */ - zswpwb_after = get_cg_wb_count(cgroup); + if (wb) + zswpwb_after = wait_for_writeback(cgroup, 5000); + else + zswpwb_after = get_cg_wb_count(cgroup); if (zswpwb_after < 0) return -1; @@ -473,7 +497,7 @@ static int test_no_invasive_cgroup_shrink(const char *root) } /* Verify that only zswapped memory from gwb_group has been written back */ - if (get_cg_wb_count(wb_group) > 0 && get_cg_wb_count(zw_group) == 0) + if (wait_for_writeback(wb_group, 5000) > 0 && get_cg_wb_count(zw_group) == 0) ret = KSFT_PASS; out: cg_enter_current(root); -- 2.53.0