From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Kiryl Shutsemau <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, Zi Yan <ziy@nvidia.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>,
"Kiryl Shutsemau (Meta)" <kas@kernel.org>
Subject: Re: [PATCH 01/12] mm/khugepaged: drop redundant mm_struct pin in madvise_collapse()
Date: Mon, 7 Sep 2026 15:33:19 +0800 [thread overview]
Message-ID: <30ab6d94-2053-4c32-88a1-36def010cb45@linux.alibaba.com> (raw)
In-Reply-To: <1ff754df1d57154e01356f35d72b1cb06c0f8664.1788533997.git.kas@kernel.org>
On 9/4/26 11:10 PM, 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: Claude-Code:claude-opus-5
> Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
> ---
LGTM.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
next prev parent reply other threads:[~2026-09-07 7:33 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 15:10 [PATCH 00/12] mm/collapse: separate a collapse from its callers Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 01/12] mm/khugepaged: drop redundant mm_struct pin in madvise_collapse() Kiryl Shutsemau
2026-09-04 15:58 ` Zi Yan
2026-09-07 7:33 ` Baolin Wang [this message]
2026-09-04 15:10 ` [PATCH 02/12] mm/khugepaged: count collapses where khugepaged makes them Kiryl Shutsemau
2026-09-05 2:25 ` Zi Yan
2026-09-07 7:40 ` Baolin Wang
2026-09-04 15:10 ` [PATCH 03/12] mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes Kiryl Shutsemau
2026-09-05 2:28 ` Zi Yan
2026-09-07 7:54 ` Baolin Wang
2026-09-07 10:35 ` Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 04/12] mm/collapse: add collapse.h for the collapse interface Kiryl Shutsemau
2026-09-05 2:36 ` Zi Yan
2026-09-07 10:41 ` Kiryl Shutsemau
2026-09-07 8:04 ` Baolin Wang
2026-09-04 15:10 ` [PATCH 05/12] mm/collapse: state what a collapse may do in the policy Kiryl Shutsemau
2026-09-05 2:44 ` Zi Yan
2026-09-07 10:49 ` Kiryl Shutsemau
2026-09-07 19:40 ` Zi Yan
2026-09-07 9:05 ` Baolin Wang
2026-09-07 10:56 ` Kiryl Shutsemau
2026-09-08 1:48 ` Baolin Wang
2026-09-04 15:10 ` [PATCH 06/12] mm/collapse: drop the collapse_possible() wrapper Kiryl Shutsemau
2026-09-05 2:45 ` Zi Yan
2026-09-07 8:28 ` Baolin Wang
2026-09-04 15:10 ` [PATCH 07/12] mm/collapse: name the per-table scan reset for what it resets Kiryl Shutsemau
2026-09-05 18:05 ` Zi Yan
2026-09-07 8:31 ` Baolin Wang
2026-09-04 15:10 ` [PATCH 08/12] mm/collapse: separate scanning a PTE table from collapsing it Kiryl Shutsemau
2026-09-06 2:30 ` Zi Yan
2026-09-07 11:34 ` Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 09/12] mm/collapse: open-code collapse_single_pmd() in its two callers Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 10/12] mm/collapse: work out the orders a VMA allows once per VMA Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 11/12] mm/collapse: declare the collapse interface in collapse.h Kiryl Shutsemau
2026-09-04 15:10 ` [PATCH 12/12] mm/collapse: implement MADV_COLLAPSE in madvise.c Kiryl Shutsemau
2026-09-06 0:23 ` [PATCH 00/12] mm/collapse: separate a collapse from its callers Andrew Morton
2026-09-07 10:28 ` Kiryl Shutsemau
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