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From: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: dma api errors with swiotlb
Date: Wed, 4 Sep 2019 15:21:55 +0200	[thread overview]
Message-ID: <d7bf95a0-e4c3-f257-77f5-c384996cf7f4@shipmail.org> (raw)
In-Reply-To: <20190904131638.GA29164@infradead.org>

On 9/4/19 3:16 PM, Christoph Hellwig wrote:
> On Wed, Sep 04, 2019 at 03:02:14PM +0200, Thomas Hellström (VMware) wrote:
>> It looks like it does that, although when we send it, the SWIOTLB error has
>> already occured and been printed out, and then the sequence starts again.
> Well, the only way to really find out is to try.  We also have a
> backoff algorithm in the SCSI midlayer, so it should not be much of
> an inpact.  If you care about the warnings they can be disabled using
> DMA_ATTR_NO_WARN.  I have to admit that I'm not even sure the warnings
> are all that useful, but that's something you need to take up with
> the swiotlb maintainer.

Yes, I guess so. I actually think the warnings make sense, since while 
the scsi midlayer handles this nicely, other drivers competing for the 
space might not.

Thanks!
Thomas



      reply	other threads:[~2019-09-04 13:22 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04  7:59 dma api errors with swiotlb Thomas Hellström (VMware)
2019-09-04 12:17 ` Christoph Hellwig
2019-09-04 12:54   ` Thomas Hellström (VMware)
2019-09-04 12:55     ` Christoph Hellwig
2019-09-04 13:02       ` Thomas Hellström (VMware)
2019-09-04 13:16         ` Christoph Hellwig
2019-09-04 13:21           ` Thomas Hellström (VMware) [this message]

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