From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
tj@kernel.org, tglx@linutronix.de, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au,
mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org,
vincent.guittot@linaro.org, sbw@mit.edu,
amit.kucheria@linaro.org, rjw@sisk.pl,
wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com,
nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 01/10] CPU hotplug: Provide APIs for "light" atomic readers to prevent CPU offline
Date: Fri, 07 Dec 2012 23:03:14 +0530 [thread overview]
Message-ID: <50C2285A.60806@linux.vnet.ibm.com> (raw)
In-Reply-To: <1354831350.17101.31.camel@gandalf.local.home>
On 12/07/2012 03:32 AM, Steven Rostedt wrote:
> On Fri, 2012-12-07 at 01:06 +0530, Srivatsa S. Bhat wrote:
>> The root-cause of this deadlock is again lock-ordering mismatch right?
>> CPU0 takes locks in order A, B
>> CPU1 takes locks in order B, A
>>
>> And the writer facilitates in actually getting deadlocked.
>>
>> I avoid this in this patchset by always taking the locks in the same
>> order. So we won't be deadlocking like this.
>
> OK, I haven't looked closely at the patch yet. I'm currently hacking on
> my own problems. But just from the description above, it looked like you
> were using rw_locks() to be able to inverse the order of the locks.
>
Ah, ok, no problem! I'd be grateful if you could take a look when you
are free :-) I'll post a v3 soon, which has a completely redesigned
synchronization scheme, to address the performance concerns related to
global rwlocks that Tejun raised.
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2012-12-07 17:34 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-05 18:42 [RFC PATCH v2 00/10][RESEND] CPU hotplug: stop_machine()-free CPU hotplug Srivatsa S. Bhat
2012-12-05 18:43 ` [RFC PATCH v2 01/10] CPU hotplug: Provide APIs for "light" atomic readers to prevent CPU offline Srivatsa S. Bhat
2012-12-05 18:47 ` Srivatsa S. Bhat
2012-12-05 18:51 ` Srivatsa S. Bhat
2012-12-05 18:53 ` Srivatsa S. Bhat
2012-12-05 18:56 ` Srivatsa S. Bhat
2012-12-05 18:59 ` Srivatsa S. Bhat
2012-12-05 20:14 ` Srivatsa S. Bhat
2012-12-06 16:18 ` Oleg Nesterov
2012-12-06 18:48 ` Srivatsa S. Bhat
2012-12-06 19:17 ` Srivatsa S. Bhat
2012-12-07 21:01 ` Oleg Nesterov
2012-12-06 19:28 ` Steven Rostedt
2012-12-06 19:36 ` Srivatsa S. Bhat
2012-12-06 22:02 ` Steven Rostedt
2012-12-07 17:33 ` Srivatsa S. Bhat [this message]
[not found] ` <20121207200014.GB13238@redhat.com>
2012-12-10 18:21 ` Oleg Nesterov
2012-12-10 19:07 ` Steven Rostedt
2012-12-07 19:56 ` Oleg Nesterov
2012-12-07 20:25 ` Srivatsa S. Bhat
2012-12-07 20:59 ` Oleg Nesterov
2012-12-05 19:07 ` Oleg Nesterov
2012-12-05 19:16 ` Srivatsa S. Bhat
2012-12-05 18:43 ` [RFC PATCH v2 02/10] CPU hotplug: Provide APIs for "full" " Srivatsa S. Bhat
2012-12-05 19:01 ` Srivatsa S. Bhat
2012-12-05 20:31 ` Srivatsa S. Bhat
2012-12-05 20:57 ` Tejun Heo
2012-12-06 4:31 ` Srivatsa S. Bhat
2012-12-05 18:43 ` [RFC PATCH v2 03/10] CPU hotplug: Convert preprocessor macros to static inline functions Srivatsa S. Bhat
2012-12-05 18:43 ` [RFC PATCH v2 04/10] smp, cpu hotplug: Fix smp_call_function_*() to prevent CPU offline properly Srivatsa S. Bhat
2012-12-05 18:43 ` [RFC PATCH v2 05/10] smp, cpu hotplug: Fix on_each_cpu_*() " Srivatsa S. Bhat
2012-12-05 18:44 ` [RFC PATCH v2 06/10] sched, cpu hotplug: Use stable online cpus in try_to_wake_up() & select_task_rq() Srivatsa S. Bhat
2012-12-05 18:44 ` [RFC PATCH v2 07/10] kick_process(), cpu-hotplug: Prevent offlining of target CPU properly Srivatsa S. Bhat
2012-12-05 18:44 ` [RFC PATCH v2 08/10] yield_to(), cpu-hotplug: Prevent offlining of other CPUs properly Srivatsa S. Bhat
2012-12-05 18:44 ` [RFC PATCH v2 09/10] kvm, vmx: Add full atomic synchronization with CPU Hotplug Srivatsa S. Bhat
2012-12-05 18:45 ` [RFC PATCH v2 10/10] cpu: No more __stop_machine() in _cpu_down() Srivatsa S. Bhat
2012-12-05 19:08 ` Oleg Nesterov
2012-12-05 19:12 ` Srivatsa S. Bhat
[not found] <20121205131038.17383.55472.stgit@srivatsabhat.in.ibm.com>
[not found] ` <20121205131136.17383.23318.stgit@srivatsabhat.in.ibm.com>
[not found] ` <20121205142316.GI3885@mtj.dyndns.org>
[not found] ` <20121205164640.GA7382@redhat.com>
[not found] ` <20121205165356.GL3885@mtj.dyndns.org>
2012-12-05 18:32 ` [RFC PATCH v2 01/10] CPU hotplug: Provide APIs for "light" atomic readers to prevent CPU offline Srivatsa S. Bhat
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