From: David Hildenbrand <david@redhat.com>
To: Lance Yang <lance.yang@linux.dev>, akpm@linux-foundation.org
Cc: lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
baohua@kernel.org, baolin.wang@linux.alibaba.com,
dev.jain@arm.com, hughd@google.com, ioworker0@gmail.com,
kirill@shutemov.name, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mpenttil@redhat.com, npache@redhat.com,
ryan.roberts@arm.com, ziy@nvidia.com, richard.weiyang@gmail.com
Subject: Re: [PATCH mm-new v2 1/1] mm/khugepaged: abort collapse scan on non-swap entries
Date: Wed, 1 Oct 2025 10:31:07 +0200 [thread overview]
Message-ID: <f07edfc2-0952-486f-ae47-5e3bbd77e4c0@redhat.com> (raw)
In-Reply-To: <20251001032251.85888-1-lance.yang@linux.dev>
On 01.10.25 05:22, Lance Yang wrote:
> From: Lance Yang <lance.yang@linux.dev>
>
> Currently, special non-swap entries (like migration, hwpoison, or PTE
> markers) are not caught early in hpage_collapse_scan_pmd(), leading to
> failures deep in the swap-in logic.
>
> hpage_collapse_scan_pmd()
> `- collapse_huge_page()
> `- __collapse_huge_page_swapin() -> fails!
>
> As David suggested[1], this patch skips any such non-swap entries
> early. If any one is found, the scan is aborted immediately with the
> SCAN_PTE_NON_PRESENT result, as Lorenzo suggested[2], avoiding wasted
> work.
>
> [1] https://lore.kernel.org/linux-mm/7840f68e-7580-42cb-a7c8-1ba64fd6df69@redhat.com
> [2] https://lore.kernel.org/linux-mm/7df49fe7-c6b7-426a-8680-dcd55219c8bd@lucifer.local
>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Signed-off-by: Lance Yang <lance.yang@linux.dev>
> ---
Could have mentioned you adjust the flow of code to resemble what we
have in __collapse_huge_page_isolate().
Acked-by: David Hildenbrand <david@redhat.com>
--
Cheers
David / dhildenb
next prev parent reply other threads:[~2025-10-01 8:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-01 3:22 Lance Yang
2025-10-01 8:31 ` David Hildenbrand [this message]
2025-10-01 9:38 ` Lance Yang
2025-10-01 8:54 ` Wei Yang
2025-10-01 9:15 ` David Hildenbrand
2025-10-01 10:05 ` Lance Yang
2025-10-01 13:52 ` Wei Yang
2025-10-05 1:05 ` Wei Yang
2025-10-05 2:12 ` Lance Yang
2025-10-06 14:18 ` David Hildenbrand
2025-10-06 15:02 ` Lance Yang
2025-10-07 10:25 ` Lance Yang
2025-10-08 1:37 ` Wei Yang
2025-10-08 9:00 ` David Hildenbrand
2025-10-01 10:20 ` Dev Jain
2025-10-01 10:48 ` Lance Yang
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