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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Stat-Signature: 611beigm84rd7nbtbo5ki374sxkkmsa3 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 830C140005 X-Rspam-User: X-HE-Tag: 1766229432-834871 X-HE-Meta: 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 6fnOJvWV jf2jDk9ke/zlrYX/2uNNjHmQUDNNDVdZoZ9RcRC3AdFZuhWjALtIXUt6EYReT2x+71oYIjy1p8SnMwFo/4+vZkc3sJiFoekNbJOFBxbnSa3NBuoL2W9NcClnOqCmndtOCKijtN3/vaUXj2N1WwbVtfiop1ztQR/pPP/cTYNPXBwabxr3qAGbWlSfj1vSdMa2hs52ECHEGAhSae49vkDjjfmLtYQEgtvEnnMH8jf4TaXd+j/z4UiYbaK9Dz/MpLTVolj6PRha/FqUgFjrTxXDL1UhOln7CJA7jEOKOL3P59PHbzAQD7nADlXC7b/nUIo2pG9btrcUhpALIzl+Q0tQiR2rYfFq6khGVrDpxpk062hY8hfRfYG2XAf5/1KfUITqh7TPTzhh9RKHe1MwCNkMUJ7Z+8g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 = 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 } +function wait_for_file_value() { + local path="$1" + local expect="$2" + local max_tries="120" + + local i cur + for ((i=1; i<=max_tries; i++)); do + cur="$(cat "$path")" + if [[ "$cur" == "$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="$1" local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_file" - # Wait for hugetlbfs memory to get depleted. - while [ $(cat $path) != 0 ]; do - echo Waiting for hugetlb memory to get depleted. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "0" } function wait_for_hugetlb_memory_to_get_reserved() { local cgroup="$1" local size="$2" - local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_file" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) != $size ]; do - echo Waiting for hugetlb memory reservation to reach size $size. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "$size" } function wait_for_hugetlb_memory_to_get_written() { local cgroup="$1" local size="$2" - local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$fault_usage_file" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) != $size ]; do - echo Waiting for hugetlb memory to reach size $size. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "$size" } function write_hugetlbfs_and_get_usage() { -- 2.49.0