From: Andrew Morton <akpm@linux-foundation.org>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Sameer Nanda <snanda@chromium.org>,
mingo@redhat.com, peterz@infradead.org, len.brown@intel.com,
pavel@ucw.cz, rjw@sisk.pl, dzickus@redhat.com, msb@chromium.org,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
olofj@chromium.org,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Subject: Re: [PATCH v2] watchdog: fix for lockup detector breakage on resume
Date: Fri, 8 Jun 2012 14:44:47 -0700 [thread overview]
Message-ID: <20120608144447.b8e2d146.akpm@linux-foundation.org> (raw)
In-Reply-To: <4FA74089.4080204@linux.vnet.ibm.com>
On Mon, 07 May 2012 08:54:57 +0530
Anshuman Khandual <khandual@linux.vnet.ibm.com> wrote:
> On Tuesday 01 May 2012 10:52 PM, Sameer Nanda wrote:
>
> > On the suspend/resume path the boot CPU does not go though an
> > offline->online transition. This breaks the NMI detector
> > post-resume since it depends on PMU state that is lost when
> > the system gets suspended.
>
>
> We should not have allowed the PMU to go with events counting on it across the suspend/resume transition
> and find out that the state has been lost. This patch solves the problem of the NMI detector as we restart the
> counter again when the boot cpu comes back online during resume. But the original cause (PMU going with
> counters into the suspend state) which triggered this problem is still there. May be we should have called
> perf_event_exit() on the boot cpu before going into the suspend state.
>
That sounds like a nicer solution.
An implementation would be nice ;) I'll keep the original patch on life
support until we get all this nailed down.
prev parent reply other threads:[~2012-06-08 21:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 18:10 [PATCH] watchdog: fix for lockup detector breakage on resume Sameer Nanda
2012-04-27 21:12 ` Andrew Morton
2012-04-27 21:33 ` Rafael J. Wysocki
2012-04-27 21:40 ` Sameer Nanda
2012-04-27 22:03 ` Andrew Morton
2012-04-27 22:20 ` Sameer Nanda
2012-04-30 6:12 ` Srivatsa S. Bhat
2012-04-30 13:05 ` Don Zickus
2012-04-30 21:10 ` Sameer Nanda
2012-05-01 17:25 ` Sameer Nanda
2012-05-02 13:14 ` Srivatsa S. Bhat
2012-05-01 17:22 ` [PATCH v2] " Sameer Nanda
2012-05-07 3:24 ` Anshuman Khandual
2012-06-08 21:44 ` Andrew Morton [this message]
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:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120608144447.b8e2d146.akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=dzickus@redhat.com \
--cc=khandual@linux.vnet.ibm.com \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=msb@chromium.org \
--cc=olofj@chromium.org \
--cc=pavel@ucw.cz \
--cc=peterz@infradead.org \
--cc=rjw@sisk.pl \
--cc=snanda@chromium.org \
--cc=srivatsa.bhat@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.