From: "David Hildenbrand (Red Hat)" <david@kernel.org>
To: Li Wang <liwang@redhat.com>
Cc: akpm@linux-foundation.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mark Brown <broonie@kernel.org>, Shuah Khan <shuah@kernel.org>,
Waiman Long <longman@redhat.com>
Subject: Re: [PATCH v2 3/3] selftests/mm/charge_reserved_hugetlb: fix hugetlbfs mount size for large hugepages
Date: Sun, 21 Dec 2025 10:49:18 +0100 [thread overview]
Message-ID: <30a75bb5-7edd-42b1-9a94-8ffe017bdb0b@kernel.org> (raw)
In-Reply-To: <CAEemH2f67p=wqGrwYnoVCP1fR82xxwJv1xfbMmFrvNaP7LZJog@mail.gmail.com>
On 12/21/25 10:44, Li Wang wrote:
> David Hildenbrand (Red Hat) <david@kernel.org> wrote:
>> On 12/21/25 09:58, Li Wang wrote:
>>> charge_reserved_hugetlb.sh mounts a hugetlbfs instance at /mnt/huge with
>>> a fixed size of 256M. On systems with large base hugepages (e.g. 512MB),
>>> this is smaller than a single hugepage, so the hugetlbfs mount ends up
>>> with effectively zero capacity (often visible as size=0 in mount output).
>>>
>>> As a result, write_to_hugetlbfs fails with ENOMEM and the test can hang
>>> waiting for progress.
>>
>> I'm curious, what's the history of using "256MB" in the first place (or
>> specifying any size?).
>
> Seems the script initializes it with "256MB" from:
>
> commit 29750f71a9b4cfae57cdddfbd8ca287eddca5503
> Author: Mina Almasry <almasrymina@google.com>
> Date: Wed Apr 1 21:11:38 2020 -0700
>
> hugetlb_cgroup: add hugetlb_cgroup reservation tests
What would happen if we don't specify a size at all?
--
Cheers
David
next prev parent reply other threads:[~2025-12-21 9:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-21 8:58 [PATCH v2 0/3] selftests/mm: hugetlb cgroup charging: robustness fixes Li Wang
2025-12-21 8:58 ` [PATCH v2 1/3] selftests/mm/write_to_hugetlbfs: parse -s as size_t Li Wang
2025-12-21 9:01 ` David Hildenbrand (Red Hat)
2025-12-21 8:58 ` [PATCH v2 2/3] selftests/mm/charge_reserved_hugetlb.sh: add waits with timeout helper Li Wang
2025-12-21 9:15 ` David Hildenbrand (Red Hat)
2025-12-21 9:35 ` Li Wang
2025-12-21 9:52 ` David Hildenbrand (Red Hat)
2025-12-21 10:08 ` Li Wang
2025-12-21 8:58 ` [PATCH v2 3/3] selftests/mm/charge_reserved_hugetlb: fix hugetlbfs mount size for large hugepages Li Wang
2025-12-21 9:17 ` David Hildenbrand (Red Hat)
2025-12-21 9:44 ` Li Wang
2025-12-21 9:49 ` David Hildenbrand (Red Hat) [this message]
2025-12-21 11:56 ` Li Wang
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