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From: Dmitry Safonov <0x7f454c46@gmail.com>
Date: Thu, 29 Mar 2018 14:52:41 +0100
Message-ID: <CAJwJo6aav1Ggsat2o9H8HL0bjTzTcjtwKPL5EU0iJQo6v5-WQA@mail.gmail.com>
Subject: Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing
To: Joerg Roedel <joro@8bytes.org>
Cc: Dmitry Safonov <dima@arista.com>,
        open list <linux-kernel@vger.kernel.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        David Woodhouse <dwmw2@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        Lu Baolu <baolu.lu@linux.intel.com>, iommu@lists.linux-foundation.org
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2018-03-29 9:50 GMT+01:00 Joerg Roedel <joro@8bytes.org>:
> On Tue, Mar 20, 2018 at 08:50:13PM +0000, Dmitry Safonov wrote:
>> Hmm, but this fixes my softlockup issue, because it's about time spent
>> in printk() inside irq-disabled section, rather about exiting the dmar-
>> clearing loop.
>> And on my hw doesn't make any difference to limit loop or not because
>> clearing a fault is much faster than hw could generate a new fault.
>> ITOW, it fixes the softlockup for me and the loop-related lockup can't
>> happen on hw I have (so it's the other issue, [possible?] on other hw).
>
> It might solve your issue, but someone else might still run into it with
> a different setup. An upstream fix needs to solve it for everyone.

Ok, I'll resend v4 with an additional patch to limit the loop.

Thanks,
             Dmitry