LKML Archive on
help / color / mirror / Atom feed
From: Dmitry Safonov <>
To: Joerg Roedel <>
	Alex Williamson <>,
	David Woodhouse <>,
	Ingo Molnar <>,
	Lu Baolu <>,
Subject: Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing
Date: Thu, 15 Mar 2018 14:34:50 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, 2018-03-15 at 15:22 +0100, Joerg Roedel wrote:
> On Thu, Mar 15, 2018 at 02:13:03PM +0000, Dmitry Safonov wrote:
> > So, you suggest to remove ratelimit at all?
> > Do we really need printk flood for each happened fault?
> > Imagine, you've hundreds of mappings and then PCI link flapped..
> > Wouldn't it be better to keep ratelimiting?
> > I don't mind, just it looks a bit strange to me.
> I never said you should remove the ratelimiting, after all you are
> trying to fix a soft-lockup, no?
> And that should not be fixed by changes to the ratelimiting, but with
> proper irq handling.

Uh, I'm a bit confused then.
- Isn't it better to ratelimit each printk() instead of bunch of
printks inside irq handler?
- I can limit the number of loops, but the most of the time is spent in
the loop on printk() (on my machine ~170msec per loop), while
everything else takes much lesser time (on my machine < 1 usec per
loop). So, if I will limit number of loops per-irq, that cycle-limit
will be based on limiting time spent on printk (e.g., how many printks
to do in atomic context so that node will not lockup). It smells like
ratelimiting, no?

I must be misunderstanding something, but why introducing another limit
for number of printk() called when there is ratelimit which may be


  reply	other threads:[~2018-03-15 14:34 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-15 19:17 Dmitry Safonov
2018-03-05 15:00 ` Dmitry Safonov
2018-03-13 16:21   ` Dmitry Safonov
2018-03-15 13:46 ` Joerg Roedel
2018-03-15 14:13   ` Dmitry Safonov
2018-03-15 14:22     ` Joerg Roedel
2018-03-15 14:34       ` Dmitry Safonov [this message]
2018-03-15 14:42         ` Dmitry Safonov
2018-03-15 15:28           ` Joerg Roedel
2018-03-15 15:54             ` Dmitry Safonov
2018-03-20 20:50             ` Dmitry Safonov
2018-03-29  8:50               ` Joerg Roedel
2018-03-29 13:52                 ` Dmitry Safonov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCHv3] iommu/intel: Ratelimit each dmar fault printing' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).