From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Kiryl Shutsemau <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Kiryl Shutsemau (Meta)" <kas@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, "Liam R. Howlett" <liam@infradead.org>,
Nico Pache <nico.pache@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Usama Arif <usama.arif@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>, Jann Horn <jannh@google.com>
Subject: Re: [PATCH v3 01/12] mm/khugepaged: drop redundant mm_struct pin in madvise_collapse()
Date: Wed, 23 Sep 2026 13:49:06 +0200 [thread overview]
Message-ID: <3d8f4dac-649c-42e0-8b51-437cf6cc65c2@kernel.org> (raw)
In-Reply-To: <20260916093145.4022188-2-kirill@shutemov.name>
On 9/16/26 11:31, Kiryl Shutsemau wrote:
> From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
>
> madvise_collapse() holds an mmgrab() reference across its work. It is
> redundant. Every caller already holds mm_users:
>
> - madvise(2) works on current->mm, which lives as long as the task is in
> the syscall;
> - process_madvise(2) reaches a remote mm through mm_access(), which takes
> an mm_users reference and holds it until the syscall returns;
> - io_uring passes current->mm;
> - DAMON takes one with get_task_mm() and drops it after the call.
>
> Drop the mmgrab()/mmdrop() pair.
>
> Assisted-by: LLM
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
> ---
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
--
Cheers,
David
next prev parent reply other threads:[~2026-09-23 11:49 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 9:31 [PATCH v3 00/12] mm/collapse: separate a collapse from its callers Kiryl Shutsemau
2026-09-16 9:31 ` [PATCH v3 01/12] mm/khugepaged: drop redundant mm_struct pin in madvise_collapse() Kiryl Shutsemau
2026-09-23 11:49 ` David Hildenbrand (Arm) [this message]
2026-09-16 9:31 ` [PATCH v3 02/12] mm/khugepaged: count collapses where khugepaged makes them Kiryl Shutsemau
2026-09-23 11:51 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 03/12] mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes Kiryl Shutsemau
2026-09-23 11:52 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 04/12] mm/collapse: add collapse.h for the collapse interface Kiryl Shutsemau
2026-09-23 11:56 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 05/12] mm/collapse: state what a collapse may do in the policy Kiryl Shutsemau
2026-09-23 12:24 ` David Hildenbrand (Arm)
2026-09-24 13:49 ` Kiryl Shutsemau
2026-09-16 9:31 ` [PATCH v3 06/12] mm/collapse: drop the collapse_possible() wrapper Kiryl Shutsemau
2026-09-23 12:25 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 07/12] mm/collapse: name the per-table scan reset for what it resets Kiryl Shutsemau
2026-09-23 12:26 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 08/12] mm/collapse: separate scanning a PTE table from collapsing it Kiryl Shutsemau
2026-09-18 9:06 ` Baolin Wang
2026-09-23 13:04 ` David Hildenbrand (Arm)
2026-09-24 14:19 ` Kiryl Shutsemau
2026-09-16 9:31 ` [PATCH v3 09/12] mm/collapse: open-code collapse_single_pmd() in its two callers Kiryl Shutsemau
2026-09-18 9:31 ` Baolin Wang
2026-09-23 13:08 ` David Hildenbrand (Arm)
2026-09-24 14:56 ` Kiryl Shutsemau
2026-09-16 9:31 ` [PATCH v3 10/12] mm/collapse: work out the orders a VMA allows once per VMA Kiryl Shutsemau
2026-09-23 13:19 ` David Hildenbrand (Arm)
2026-09-24 15:04 ` Kiryl Shutsemau
2026-09-16 9:31 ` [PATCH v3 11/12] mm/collapse: declare the collapse interface in collapse.h Kiryl Shutsemau
2026-09-23 13:34 ` David Hildenbrand (Arm)
2026-09-24 15:22 ` Kiryl Shutsemau
2026-09-28 12:03 ` David Hildenbrand (Arm)
2026-09-16 9:31 ` [PATCH v3 12/12] mm/collapse: implement MADV_COLLAPSE in madvise.c Kiryl Shutsemau
2026-09-16 22:48 ` [PATCH v3 00/12] mm/collapse: separate a collapse from its callers Andrew Morton
2026-09-17 12:26 ` Kiryl Shutsemau
2026-09-17 22:11 ` Andrew Morton
2026-09-23 13:52 ` David Hildenbrand (Arm)
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