From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Rusty Russell <rusty@rustcorp.com.au>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Namhyung Kim <namhyung@kernel.org>
Subject: Re: [Patch 3/7] smpboot: Provide infrastructure for percpu hotplug threads
Date: Sat, 21 Jul 2012 23:31:16 +0530 [thread overview]
Message-ID: <500AEE6C.8060506@linux.vnet.ibm.com> (raw)
In-Reply-To: <500A75D7.3070706@linux.vnet.ibm.com>
On 07/21/2012 02:56 PM, Srivatsa S. Bhat wrote:
> On 07/16/2012 04:12 PM, Thomas Gleixner wrote:
>> Provide a generic interface for setting up and tearing down percpu
>> threads.
>>
>> On registration the threads for already online cpus are created and
>> started. On deregistration (modules) the threads are stoppped.
>>
>> During hotplug operations the threads are created, started, parked and
>> unparked. The datastructure for registration provides a pointer to
>> percpu storage space and optional setup, cleanup, park, unpark
>> functions. These functions are called when the thread state changes.
>>
>> Each implementation has to provide a function which is queried and
>> returns whether the thread should run and the thread function itself.
>>
>> The core code handles all state transitions and avoids duplicated code
>> in the call sites.
>>
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>
> Elegant design and very beautiful code!
> It was such a pleasure to read and review it :-)
>
> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
>
Of course, the preempt imbalance needs to get resolved, as pointed out
by Paul... Your patchset + his fix worked fine, without throwing any
scheduling-while-atomic splats.
Regards,
Srivatsa S. Bhat
> [ A minor nit below ]
>
>> ---
>> include/linux/smpboot.h | 43 +++++++++
>> kernel/cpu.c | 10 +-
>> kernel/smpboot.c | 229 ++++++++++++++++++++++++++++++++++++++++++++++++
>> kernel/smpboot.h | 4
>> 4 files changed, 285 insertions(+), 1 deletion(-)
>>
>> +
>> +/**
>> + * smpboot_thread_fn - percpu hotplug thread loop function
>> + * @void: thread data pointer
>
> s/void/data
>
>> + *
>> + * Checks for thread stop and park conditions. Calls the necessary
>> + * setup, cleanup, park and unpark functions for the registered
>> + * thread.
>> + *
>> + * Returns 1 when the thread should exit, 0 otherwise.
>> + */
>> +static int smpboot_thread_fn(void *data)
>> +{
>> + struct smpboot_thread_data *td = data;
>> + struct smp_hotplug_thread *ht = td->ht;
>> +
>
> Regards,
> Srivatsa S. Bhat
>
--
Regards,
Srivatsa S. Bhat
IBM Linux Technology Center
next prev parent reply other threads:[~2012-07-21 18:02 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-16 10:42 [Patch 0/7] Per cpu thread hotplug infrastructure - V3 Thomas Gleixner
2012-07-16 10:42 ` [Patch 1/7] rcu: Yield simpler Thomas Gleixner
2012-08-13 15:07 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-07-16 10:42 ` [Patch 3/7] smpboot: Provide infrastructure for percpu hotplug threads Thomas Gleixner
2012-07-21 9:26 ` Srivatsa S. Bhat
2012-07-21 18:01 ` Srivatsa S. Bhat [this message]
2012-07-21 17:12 ` Paul E. McKenney
2012-08-13 15:10 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-09-19 21:47 ` [Patch 3/7] " Sasha Levin
2012-10-12 1:39 ` Sasha Levin
2012-07-16 10:42 ` [Patch 2/7] kthread: Implement park/unpark facility Thomas Gleixner
2012-07-21 9:31 ` Srivatsa S. Bhat
2012-08-13 15:08 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-07-16 10:42 ` [Patch 4/7] softirq: Use hotplug thread infrastructure Thomas Gleixner
2012-07-21 17:21 ` Paul E. McKenney
2012-07-23 21:15 ` Paul E. McKenney
2012-07-25 14:21 ` JoonSoo Kim
2012-08-13 15:12 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-07-16 10:42 ` [Patch 6/7] rcu: Use smp_hotplug_thread facility for RCUs per-CPU kthread Thomas Gleixner
2012-07-16 16:59 ` Paul E. McKenney
2012-08-13 15:13 ` [tip:smp/hotplug] " tip-bot for Paul E. McKenney
2012-07-16 10:42 ` [Patch 5/7] watchdog: Use hotplug thread infrastructure Thomas Gleixner
2012-08-13 15:13 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-08-14 7:20 ` viresh kumar
2012-08-14 8:42 ` Thomas Gleixner
2012-07-16 10:42 ` [Patch 7/7] infiniband: ehca: " Thomas Gleixner
2012-07-17 0:27 ` Rusty Russell
2012-08-13 15:14 ` [tip:smp/hotplug] infiniband: Ehca: " tip-bot for Thomas Gleixner
2012-07-16 15:22 ` [Patch 0/7] Per cpu thread hotplug infrastructure - V3 Paul E. McKenney
2012-07-18 17:36 ` Srivatsa S. Bhat
2012-07-18 23:54 ` Paul E. McKenney
2012-07-20 13:17 ` Srivatsa S. Bhat
2012-07-20 14:35 ` Paul E. McKenney
2012-07-20 15:00 ` Srivatsa S. Bhat
2012-07-20 17:53 ` Paul E. McKenney
2012-07-20 18:28 ` Srivatsa S. Bhat
2012-07-25 12:25 ` Srivatsa S. Bhat
2012-07-25 14:25 ` JoonSoo Kim
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