From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Venkatesh Pallipadi <venki@google.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
linux-kernel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] generic-ipi: fix deadlock in __smp_call_function_single
Date: Sun, 26 Sep 2010 14:59:45 +0200 [thread overview]
Message-ID: <20100926125945.GA2597@osiris.boeblingen.de.ibm.com> (raw)
In-Reply-To: <20100926084233.GA28809@elte.hu>
On Sun, Sep 26, 2010 at 10:42:33AM +0200, Ingo Molnar wrote:
>
> * Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > Maybe. Or maybe it papers over a scheduler bug by gratuitously adding
> > additional code which no present callsites actually need.
>
> Hm, indeed.
>
> We now have the scheduler bug fixed upstream. Do we really need this
> patch?
General consensus was that it is good if smp_call_function_single() and
__smp_call_function_single() would behave the same if remote cpu == current
cpu.
If you're not applying this patch then at least at a WARN_ON() which triggers
when remote cpu == current cpu. I don't want to debug something like this
again.
> > The patch didn't update the __smp_call_function_single() kerneldoc.
> > Compare it with smp_call_function_single() and note the subtle
> > difference between "a specific CPU" and the now incorrect "on another
> > CPU".
>
> In any case this feedback didnt get addressed AFAICS.
It did get addressed in an updated patch which is the one which you
applied: http://lkml.org/lkml/2010/9/10/245
next prev parent reply other threads:[~2010-09-26 13:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-09 13:50 [PATCH] generic-ipi: fix deadlock in __smp_call_function_single Heiko Carstens
2010-09-10 11:06 ` Peter Zijlstra
2010-09-10 11:23 ` Jens Axboe
2010-09-10 11:47 ` Heiko Carstens
2010-09-10 15:47 ` [tip:core/urgent] generic-ipi: Fix " tip-bot for Heiko Carstens
2010-09-11 0:28 ` [PATCH] generic-ipi: fix " Andrew Morton
2010-09-11 9:20 ` Peter Zijlstra
2010-09-11 16:42 ` Venkatesh Pallipadi
2010-09-13 8:08 ` Heiko Carstens
2010-09-13 18:02 ` Suresh Siddha
2010-09-14 8:03 ` Peter Zijlstra
2010-09-14 11:19 ` Heiko Carstens
2010-09-17 22:12 ` Suresh Siddha
2010-09-18 15:18 ` Peter Zijlstra
2010-09-21 14:13 ` [tip:sched/urgent] sched: Fix nohz balance kick tip-bot for Suresh Siddha
2010-09-26 8:42 ` [PATCH] generic-ipi: fix deadlock in __smp_call_function_single Ingo Molnar
2010-09-26 12:59 ` Heiko Carstens [this message]
2010-09-26 16:23 ` Ingo Molnar
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