From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will.deacon@arm.com>,
Drew Richardson <drew.richardson@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Arnaldo <acme@redhat.com>, Pawel Moll <Pawel.Moll@arm.com>,
Wade Cherry <Wade.Cherry@arm.com>
Subject: Re: Perf Oops on 3.14-rc2
Date: Wed, 19 Feb 2014 19:36:23 +0100 [thread overview]
Message-ID: <20140219183623.GL27965@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CABPqkBQS355_XW-2KthkdZkzQnApRvOpANkB3SnfFyac-qsJaw@mail.gmail.com>
On Wed, Feb 19, 2014 at 07:03:13PM +0100, Stephane Eranian wrote:
> I am trying to understand the context here.
> Are you saying, we may call an offline CPU?
Yes, that is what's happening.
> I saw that sometimes you retry, sometimes you don't.
I tried to do exactly what we do for the task case which is far more
likely to fail. Could be I messed up.
I should probably write the function differently and have a common retry
path instead of duplicating everything.
> For perf_cgroup_attach(), we invoke task_function_call()
> to force a PMU context switch on the task which is now monitored in cgroup mode.
> If the CPU is offline then, the task is switched out and monitoring
> has been stoppe,
> no need to retry or do anything more.
>
> For perf_cgroup_exit(), this is pretty much the same logic.
>
> am I missing anything else?
Don't think so; I'll add a comment there. I was just too tired to make
sense of things.
next prev parent reply other threads:[~2014-02-19 18:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-10 22:17 Perf Oops on 3.14-rc2 Drew Richardson
2014-02-18 10:18 ` Will Deacon
2014-02-18 10:52 ` Peter Zijlstra
2014-02-18 11:03 ` Will Deacon
2014-02-18 10:54 ` Peter Zijlstra
2014-02-18 11:01 ` Will Deacon
2014-02-19 16:28 ` Peter Zijlstra
2014-02-19 18:03 ` Stephane Eranian
2014-02-19 18:36 ` Peter Zijlstra [this message]
2014-02-19 19:59 ` Stephane Eranian
2014-02-19 20:24 ` Peter Zijlstra
2014-02-19 19:37 ` Drew Richardson
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