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Subject: Re: Poor windows VFIO performance, GPU stalls (bisected)
From:   Chris Wilson <chris@chris-wilson.co.uk>
Cc:     hdanton@sina.com, tj@kernel.org, jiangshanlai@gmail.com,
        linux-kernel@vger.kernel.org
To:     Alex Williamson <alex.williamson@redhat.com>,
        Geoffrey McRae <geoff@hostfission.com>
Date:   Sun, 26 Jul 2020 15:15:49 +0100
Message-ID: <159577294913.1157.91069469417568930@build.alporthouse.com>
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Quoting Alex Williamson (2020-07-26 14:30:52)
> On Sun, 26 Jul 2020 17:49:07 +1000
> Geoffrey McRae <geoff@hostfission.com> wrote:
> 
> > Hi All,
> > 
> > The commit 22540ca3d00d2990a4148a13b92209c3dc5422db causes a Windows KVM 
> > guest running under QEMU with a VFIO passthrough GPU to randomly stall 
> > when using the GPU leading to the guest assuming that the driver has 
> > hung. Reverting this commit resolves the problem.
> 
> Please double check this commit ID, I can't find it in mainline or
> linux-next.  Thanks,

See commit aa202f1f5696 ("workqueue: don't use wq_select_unbound_cpu()
for bound works"). 22540ca3 is the cherry-pick into v5.4.26
-Chris