From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>, SeongJae Park <sj@kernel.org>
Cc: Usama Arif <usama.arif@linux.dev>,
npache@redhat.com, ziy@nvidia.com, willy@infradead.org,
linux-mm@kvack.org, matthew.brost@intel.com,
joshua.hahnjy@gmail.com, hannes@cmpxchg.org, rakie.kim@sk.com,
byungchul@sk.com, gourry@gourry.net,
ying.huang@linux.alibaba.com, apopple@nvidia.com,
linux-kernel@vger.kernel.org, kernel-team@meta.com,
richard.weiyang@gmail.com, stable@vger.kernel.org
Subject: Re: [PATCH v3] mm: migrate: requeue destination folio on deferred split queue
Date: Fri, 20 Mar 2026 12:41:00 +0100 [thread overview]
Message-ID: <fac42585-ea97-4002-b35d-77a80d329103@kernel.org> (raw)
In-Reply-To: <20260314172321.3ca062bb70e51fefa633a6fe@linux-foundation.org>
On 3/15/26 01:23, Andrew Morton wrote:
> On Sat, 14 Mar 2026 17:05:54 -0700 SeongJae Park <sj@kernel.org> wrote:
>
>> Because THPs are
>> removed from the deferred_list, THP shinker cannot split the underutilized THPs
>> in time. As a result, users will show less free memory than before.
>
> That'll do, thanks ;)
>
> Pasted, added cc:stable. It's been there since 6.12 so I don't see a
> need to rush this in, so I won't move this into mm-hotfixes - it'll go
> into mainline for 7.1-rc1 after which -stable should pick it up.
Makes sense. I guess using the partially-mapped is only a slight
problem, because we usually try to split partially-mapped before migrating.
So it's mostly about over-allocated THPs (mostly 0) not getting scanned
and split+reclaimed after they were migrated.
Under memory pressure without swap, that might create a user-visible
problem, especially when many such THPs are migrated before being
scanned for zeropages that can be reclaimed.
--
Cheers,
David
next prev parent reply other threads:[~2026-03-20 11:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-12 10:47 [PATCH v3] mm: migrate: requeue destination folio on deferred split queue Usama Arif
2026-03-12 14:27 ` Johannes Weiner
2026-03-13 0:16 ` SeongJae Park
2026-03-13 0:52 ` Andrew Morton
2026-03-13 10:40 ` Usama Arif
2026-03-14 22:40 ` Andrew Morton
2026-03-15 0:05 ` SeongJae Park
2026-03-15 0:23 ` Andrew Morton
2026-03-20 11:41 ` David Hildenbrand (Arm) [this message]
2026-03-13 1:18 ` Wei Yang
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