From: Kiryl Shutsemau <kirill@shutemov.name>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
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 v4 08/13] mm/collapse: call collapse_file() from collapse_single_pmd()
Date: Fri, 2 Oct 2026 12:08:11 +0100 [thread overview]
Message-ID: <ar-QK2P_3Lc_YCkd@thinkstation> (raw)
In-Reply-To: <67034af3-9849-49ab-8904-6d661178222f@kernel.org>
On Thu, Oct 01, 2026 at 10:08:09AM +0200, David Hildenbrand (Arm) wrote:
> On 9/28/26 12:06, Kiryl Shutsemau wrote:
> > From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
> >
> > collapse_scan_file() reads the page cache to decide whether a table is
> > worth collapsing and, when it is, calls collapse_file() itself. The
> > caller cannot get between the decision and the collapse.
> >
> > Move the collapse_file() call up into collapse_single_pmd(), so the scan
> > stops at the decision.
> >
> > Two things change with it. The writeback retry re-runs collapse_file()> alone instead of rescanning first; collapse_file() repeats the scan's
> > checks under the page cache lock anyway.
>
> That change wasn't actually required for "call collapse_file() from
> collapse_single_pmd()", right? You merely decided to move the retry label in the
> same patch.
Yep.
Once collapse_file() is called from here the retry can go around the
collapse alone or around the scan as well.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-10-02 11:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 10:06 [PATCH v4 00/13] mm/collapse: separate a collapse from its callers Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 01/13] mm/khugepaged: drop redundant mm_struct pin in madvise_collapse() Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 02/13] mm/khugepaged: count collapses where khugepaged makes them Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 03/13] mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 04/13] mm/collapse: add collapse.h for the collapse interface Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 05/13] mm/collapse: state what a collapse may do in the policy Kiryl Shutsemau
2026-09-28 19:26 ` David Hildenbrand (Arm)
2026-09-29 1:32 ` Zi Yan
2026-09-29 8:12 ` Baolin Wang
2026-09-28 10:06 ` [PATCH v4 06/13] mm/collapse: drop the collapse_possible() wrapper Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 07/13] mm/collapse: name the per-table scan reset for what it resets Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 08/13] mm/collapse: call collapse_file() from collapse_single_pmd() Kiryl Shutsemau
2026-09-29 1:41 ` Zi Yan
2026-10-02 11:04 ` Kiryl Shutsemau
2026-10-01 8:08 ` David Hildenbrand (Arm)
2026-10-02 11:08 ` Kiryl Shutsemau [this message]
2026-09-28 10:06 ` [PATCH v4 09/13] mm/collapse: separate scanning a PTE table from collapsing it Kiryl Shutsemau
2026-09-29 1:52 ` Zi Yan
2026-10-01 8:34 ` David Hildenbrand (Arm)
2026-10-02 11:16 ` Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 10/13] mm/collapse: open-code collapse_single_pmd() in its two callers Kiryl Shutsemau
2026-10-01 9:37 ` David Hildenbrand (Arm)
2026-10-02 14:27 ` Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 11/13] mm/collapse: work out the orders a VMA allows once per VMA Kiryl Shutsemau
2026-09-28 10:06 ` [PATCH v4 12/13] mm/collapse: declare the collapse interface in collapse.h Kiryl Shutsemau
2026-09-29 2:02 ` Zi Yan
2026-09-28 10:06 ` [PATCH v4 13/13] mm/collapse: implement MADV_COLLAPSE in madvise.c Kiryl Shutsemau
2026-09-29 2:03 ` Zi Yan
2026-09-28 21:59 ` [PATCH v4 00/13] mm/collapse: separate a collapse from its callers Andrew Morton
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