From nobody Sun Feb 8 18:49:41 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 F21E46F2F2 for ; Sat, 20 Dec 2025 11:17:10 +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=1766229432; cv=none; b=mW6uHFm1mymrKk1XTfcxWXAGY21knm+vSt5+S6Au7+A8kuajxrQLQ5B+e98XbCoFM1Q02Rq5N4zDFywvFeVrPlyQFV3BpXLEN7r3OxrUAvSwgKunDgIRwidIqE3F7Y/UQvoh8uYTAPzkEZ9QXSuwGyBzyoDjqBAhPyW5Fvx3bFg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766229432; c=relaxed/simple; bh=pVvObGlmoXaYv72+/xpcjgkdU9ns+C2pRLp5LLfe+tY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NHRL8/HnxUzNF7AU4ZZcKkPpJzL5dC/s1daZriWUMeiFRBfgHpCwlriL3UrY7WtXFOGjOF2l/hRrOj7fZ5HH03io6i+t4aNh51KafepY2CfTLiKOjxsVbP4tOjKFndDOrcE4dM0FsyOCsxmhlLw5LrhyGjDncfmq4ssbWbeGi5c= 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=KHxD0LVj; 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="KHxD0LVj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1766229429; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MoEkhGDkCRG45o46/v13ZWZW2kUp5bUq6J0F6pVCYGY=; b=KHxD0LVjhPtiDAv+GcYhrk92jtlNnXuvIcVObqarHmbNiJayME5ohVpIMEbekA1XPl4prB DKV202ZqKgwCTzX7WT6zY4sA94h9EELucoMuhKvEk0eL6sfaDCN1i7WJvwnib9SPyoiP6t mjuBX8df4lQbCLXlFmbWFnWEEcsA6KQ= Received: from mx-prod-mc-01.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-299-SCxEloExNByrp4qCAn0xiQ-1; Sat, 20 Dec 2025 06:17:07 -0500 X-MC-Unique: SCxEloExNByrp4qCAn0xiQ-1 X-Mimecast-MFC-AGG-ID: SCxEloExNByrp4qCAn0xiQ_1766229426 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5406B1956054; Sat, 20 Dec 2025 11:17:06 +0000 (UTC) Received: from dell-per7425-02.rhts.eng.pek2.redhat.com (dell-per7425-02.rhts.eng.pek2.redhat.com [10.73.116.18]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8C80A180035A; Sat, 20 Dec 2025 11:17:02 +0000 (UTC) From: Li Wang To: linux-kselftest@vger.kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: David Hildenbrand , Mark Brown , Shuah Khan , Waiman Long Subject: [PATCH 2/3] selftests/mm/charge_reserved_hugetlb.sh: add waits with timeout helper Date: Sat, 20 Dec 2025 19:16:44 +0800 Message-ID: <20251220111645.2246009-3-liwang@redhat.com> In-Reply-To: <20251220111645.2246009-1-liwang@redhat.com> References: <20251220111645.2246009-1-liwang@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" The hugetlb cgroup usage wait loops in charge_reserved_hugetlb.sh were unbounded and could hang forever if the expected cgroup file value never appears (e.g. due to bugs, timing issues, or unexpected behavior). --- Error log --- # uname -r 6.12.0-xxx.el10.aarch64+64k # ls /sys/kernel/mm/hugepages/hugepages-* hugepages-16777216kB/ hugepages-2048kB/ hugepages-524288kB/ #./charge_reserved_hugetlb.sh -cgroup-v2 # ----------------------------------------- ... # nr hugepages =3D 10 # writing cgroup limit: 5368709120 # writing reseravation limit: 5368709120 ... # write_to_hugetlbfs: Error mapping the file: Cannot allocate memory # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 ... Introduce a small helper, wait_for_file_value(), and use it for: - waiting for reservation usage to drop to 0, - waiting for reservation usage to reach a given size, - waiting for fault usage to reach a given size. This makes the waits consistent and adds a hard timeout (120 tries with 0.5s sleep) so the test fails instead of stalling indefinitely. Signed-off-by: Li Wang Cc: David Hildenbrand Cc: Mark Brown Cc: Shuah Khan Cc: Waiman Long --- .../selftests/mm/charge_reserved_hugetlb.sh | 45 ++++++++++--------- 1 file changed, 25 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh b/tools/= testing/selftests/mm/charge_reserved_hugetlb.sh index e1fe16bcbbe8..6aa4ce66922c 100755 --- a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh +++ b/tools/testing/selftests/mm/charge_reserved_hugetlb.sh @@ -112,41 +112,46 @@ function setup_cgroup() { fi } =20 +function wait_for_file_value() { + local path=3D"$1" + local expect=3D"$2" + local max_tries=3D"120" + + local i cur + for ((i=3D1; i<=3Dmax_tries; i++)); do + cur=3D"$(cat "$path")" + if [[ "$cur" =3D=3D "$expect" ]]; then + return 0 + fi + echo "Waiting for $path to become '$expect' (current: '$cur') (try $i/= $max_tries)" + sleep 0.5 + done + + echo "ERROR: timeout waiting for $path to become '$expect' (last: '$cur'= )" + return 1 +} + function wait_for_hugetlb_memory_to_get_depleted() { local cgroup=3D"$1" local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_fi= le" - # Wait for hugetlbfs memory to get depleted. - while [ $(cat $path) !=3D 0 ]; do - echo Waiting for hugetlb memory to get depleted. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "0" } =20 function wait_for_hugetlb_memory_to_get_reserved() { local cgroup=3D"$1" local size=3D"$2" - local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_fi= le" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) !=3D $size ]; do - echo Waiting for hugetlb memory reservation to reach size $size. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "$size" } =20 function wait_for_hugetlb_memory_to_get_written() { local cgroup=3D"$1" local size=3D"$2" - local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$fault_usage_file" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) !=3D $size ]; do - echo Waiting for hugetlb memory to reach size $size. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "$size" } =20 function write_hugetlbfs_and_get_usage() { --=20 2.49.0