From: John Hubbard <jhubbard@nvidia.com>
To: David Hildenbrand <david@redhat.com>,
Jaewon Kim <jaewon31.kim@gmail.com>,
zhaoyang.huang@unisoc.com
Cc: surenb@google.com, linux-mm@kvack.org
Subject: Re: [RFC] pin_user_pages_fast failure count increased
Date: Mon, 28 Apr 2025 14:12:57 -0700 [thread overview]
Message-ID: <2aa1cafb-bb9a-4540-9552-7f56bf1fb911@nvidia.com> (raw)
In-Reply-To: <3d0b8c8b-b707-4a49-99f9-09aadfc27432@redhat.com>
On 4/28/25 1:56 PM, David Hildenbrand wrote:
> On 28.04.25 22:14, John Hubbard wrote:
>> On 4/28/25 8:17 AM, Jaewon Kim wrote:
>>> Hi
>>>
>>> If pin_user_pages_fast does not pin all the requested number of pages,
>>> then drivers calling to pin_user_pages_fast should retry until the gup
>>> pins all?
>>>
>>
>> Approaches vary, for handling partial success of pin_user_pages().
>>
>> * Many drivers unpin everything and either bail out entirely, or retry
>> pinning the entire original range.
>
> Hm, unpinning + trying to repin the entire range can easily result in an
> endless loop on persistent errors IIRC?
>
I vaguely recall a limited number of retries, yes.
thanks,
--
John Hubbard
next prev parent reply other threads:[~2025-04-28 21:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-28 15:17 Jaewon Kim
2025-04-28 15:21 ` David Hildenbrand
2025-04-28 20:14 ` John Hubbard
2025-04-28 20:56 ` David Hildenbrand
2025-04-28 21:12 ` John Hubbard [this message]
[not found] ` <CGME20250522092944epcas2p1ca46168564555aad6d9880bda26ec8de@epcas2p1.samsung.com>
2025-05-22 9:27 ` Hyesoo Yu
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