linux-kernel - Re: [PATCH 3/4] amd/amdkfd: WQ_PERCPU added to alloc

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Message-ID: <42c631c7-7773-b029-6d59-a54112363a71@amd.com>
Date: Fri, 31 Oct 2025 09:12:20 -0400
From: Philip Yang <yangp@....com>
To: Marco Crivellari <marco.crivellari@...e.com>,
 Christian König <christian.koenig@....com>
Cc: linux-kernel@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, Tejun Heo <tj@...nel.org>,
 Lai Jiangshan <jiangshanlai@...il.com>,
 Frederic Weisbecker <frederic@...nel.org>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 Michal Hocko <mhocko@...e.com>, Alex Deucher <alexander.deucher@....com>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 "Yang, Philip" <Philip.Yang@....com>,
 "Kuehling, Felix" <Felix.Kuehling@....com>
Subject: Re: [PATCH 3/4] amd/amdkfd: WQ_PERCPU added to alloc_workqueue users


On 2025-10-31 04:48, Marco Crivellari wrote:
> On Thu, Oct 30, 2025 at 6:15 PM Christian König
> <christian.koenig@....com> wrote:
>> [...]
>> Adding Philip and Felix to comment, but this should most likely also not execute on the same CPU as the one who scheduled the work.
> Hi Christian,
>
> The actual behavior without WQ_PERCPU is exactly the same: with 0 it
> means the workqueue is per-cpu. We just enforced that, adding the
> WQ_PERCPU flag, so that it is explicit.
>
> So if you need this to be unbound, I can send the v2 with WQ_UNBOUND
> instead of WQ_PERCPU.
Hi,

WQ_UNBOUND is more appropriate here, to execute the KFD release work immediately as long as CPU resource is available, not specific to the CPU that kfd_unref_process the last process refcount.

Thanks,
Philip

> Thanks!
>
> --
>
> Marco Crivellari
>
> L3 Support Engineer, Technology & Product