2023-06-10 03:27:35

by Xianting Tian

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Subject: Re: [PATCH 1/3] virtio-crypto: fixup potential cpu stall when free unused bufs


在 2023/6/9 下午11:57, Michael S. Tsirkin 写道:
> On Fri, Jun 09, 2023 at 09:18:15PM +0800, Xianting Tian wrote:
>> From: Xianting Tian <[email protected]>
>>
>> Cpu stall issue may happen if device is configured with multi queues
>> and large queue depth, so fix it.
> What does "may happen" imply exactly?
> was this observed?
I didn't met such issue, this patch set just a theoretical fix.
>
>> Signed-off-by: Xianting Tian <[email protected]>
>> ---
>> drivers/crypto/virtio/virtio_crypto_core.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/crypto/virtio/virtio_crypto_core.c b/drivers/crypto/virtio/virtio_crypto_core.c
>> index 1198bd306365..94849fa3bd74 100644
>> --- a/drivers/crypto/virtio/virtio_crypto_core.c
>> +++ b/drivers/crypto/virtio/virtio_crypto_core.c
>> @@ -480,6 +480,7 @@ static void virtcrypto_free_unused_reqs(struct virtio_crypto *vcrypto)
>> kfree(vc_req->req_data);
>> kfree(vc_req->sgs);
>> }
>> + cond_resched();
>> }
>> }
>>
>> --
>> 2.17.1


2023-06-10 07:02:17

by Greg KH

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Subject: Re: [PATCH 1/3] virtio-crypto: fixup potential cpu stall when free unused bufs

On Sat, Jun 10, 2023 at 11:20:49AM +0800, Xianting Tian wrote:
>
> 在 2023/6/9 下午11:57, Michael S. Tsirkin 写道:
> > On Fri, Jun 09, 2023 at 09:18:15PM +0800, Xianting Tian wrote:
> > > From: Xianting Tian <[email protected]>
> > >
> > > Cpu stall issue may happen if device is configured with multi queues
> > > and large queue depth, so fix it.
> > What does "may happen" imply exactly?
> > was this observed?
> I didn't met such issue, this patch set just a theoretical fix.

Then I would not recommend adding it at this time, as you just slowed
down the kernel for something that no one has reported :(

thanks,

greg k-h