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b618876f2e
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 write_to_hugetlbfs in Error mapping). === 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 (60 tries with 1s sleep) so the test fails instead of stalling indefinitely. Link: https://lkml.kernel.org/r/20251221122639.3168038-4-liwang@redhat.com Signed-off-by: Li Wang <liwang@redhat.com> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>