From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Ye Liu <ye.liu@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Xin Hao <xhao@linux.alibaba.com>
Cc: Ye Liu <liuye@kylinos.cn>, Zi Yan <ziy@nvidia.com>,
"Liam R. Howlett" <liam@infradead.org>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Andrew Morton <akpm@linux-foudation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure
Date: Wed, 6 May 2026 13:17:29 +0800 [thread overview]
Message-ID: <8fa3ddff-b717-4804-b524-9b2c0447c60c@linux.alibaba.com> (raw)
In-Reply-To: <20260506012130.9306-1-ye.liu@linux.dev>
On 5/6/26 9:21 AM, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
>
> __khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the
> corresponding mm_slot. If mm_slot_alloc() fails, the function
> returns with the flag set but without inserting the mm into the
> khugepaged tracking structures.
>
> This leaves the mm in an inconsistent state: it is marked as
> registered (MMF_VM_HUGEPAGE set), but will never be scanned by
> khugepaged. Future attempts to register the mm are skipped since
> khugepaged_enter_vma() checks the flag and returns early.
>
> Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails,
> restoring the ability to retry registration later.
>
> Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for struct mm_slot")
> Signed-off-by: Ye Liu <liuye@kylinos.cn>
> ---
Good catch. Feel free to add:
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
next prev parent reply other threads:[~2026-05-06 5:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-06 1:21 [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure Ye Liu
2026-05-06 2:05 ` Lance Yang
2026-05-06 5:17 ` Baolin Wang [this message]
2026-05-06 6:46 ` Dev Jain
2026-05-06 10:51 ` Lance Yang
2026-05-08 21:41 ` David Hildenbrand (Arm)
2026-05-09 1:57 ` Lance Yang
2026-05-11 4:00 ` Dev Jain
2026-05-11 5:40 ` David Hildenbrand (Arm)
2026-05-11 5:44 ` Dev Jain
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