From: "Huang, Ying" <ying.huang@linux.alibaba.com>
To: John Hubbard <jhubbard@nvidia.com>,
"David Hildenbrand (Arm)" <david@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Zi Yan <ziy@nvidia.com>,
Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Gregory Price <gourry@gourry.net>,
Alistair Popple <apopple@nvidia.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Chris Li <chrisl@kernel.org>, Kairui Song <kasong@tencent.com>,
Kemeng Shi <shikemeng@huaweicloud.com>,
Nhat Pham <nphamcs@gmail.com>, Baoquan He <bhe@redhat.com>,
Barry Song <baohua@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [RFC PATCH 0/2] mm/migrate: wait for folio refcount during longterm pin migration
Date: Wed, 22 Apr 2026 09:46:26 +0800 [thread overview]
Message-ID: <878qafix71.fsf@DESKTOP-5N7EMDA> (raw)
In-Reply-To: <51168a90-d6ad-4429-8043-3dfdd81cb9a3@kernel.org> (David Hildenbrand's message of "Tue, 21 Apr 2026 18:00:28 +0200")
"David Hildenbrand (Arm)" <david@kernel.org> writes:
> On 4/21/26 11:19, Huang, Ying wrote:
>> Hi, John,
>>
>> John Hubbard <jhubbard@nvidia.com> writes:
>>
>>> Hi,
>>>
>>> This adds a bounded sleep to migration so that FOLL_LONGTERM pinning can
>>> wait for transient folio references to drain, instead of failing after a
>>> fixed number of retries. The wait uses a one-second timeout. An
>>
>> Is the one-second timeout appropriate for all users? Do some users
>> prefer fail-fast behavior instead? If so, should we add another FOLL
>> flag to support a timed wait?
>
> We should avoid a FOLL flag to affect that behavior. FOLL_LONGTERM
> already implies that things could take a while.
Yes. I am just not sure whether one-second is OK for all users.
> So we have real examples were failing is even desirable? :)
Hi, John,
Could you do some research on this?
---
Best Regards,
Huang, Ying
prev parent reply other threads:[~2026-04-22 1:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 3:23 [RFC PATCH 0/2] mm/migrate: wait for folio refcount during longterm pin migration John Hubbard
2026-04-10 3:23 ` [RFC PATCH 1/2] mm: wake up folio refcount waiters on folio_put() John Hubbard
2026-04-10 3:23 ` [RFC PATCH 2/2] mm/migrate: wait for folio refcount during longterm pin migration John Hubbard
2026-04-21 5:57 ` Alistair Popple
2026-04-21 9:21 ` Huang, Ying
2026-04-21 5:52 ` [RFC PATCH 0/2] " Alistair Popple
2026-04-21 9:19 ` Huang, Ying
2026-04-21 16:00 ` David Hildenbrand (Arm)
2026-04-22 1:46 ` Huang, Ying [this message]
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