linux-kernel - Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing

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Date:   Thu, 29 Mar 2018 10:50:18 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Dmitry Safonov <dima@...sta.com>
Cc:     linux-kernel@...r.kernel.org, 0x7f454c46@...il.com,
        Alex Williamson <alex.williamson@...hat.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        iommu@...ts.linux-foundation.org
Subject: Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing

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.

Thanks,

	Joerg