From: Rusty Russell <rusty@rustcorp.com.au>
To: ego@in.ibm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Dipankar Sarma <dipankar@in.ibm.com>,
Oleg Nesterov <oleg@tv-sign.ru>, Ingo Molnar <mingo@elte.hu>,
Paul E McKenney <paulmck@us.ibm.com>
Subject: Re: [RFC PATCH 1/4] Refcount Based Cpu-Hotplug Implementation
Date: Wed, 17 Oct 2007 10:47:41 +1000 [thread overview]
Message-ID: <200710171047.42693.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20071016103417.GA16570@in.ibm.com>
On Tuesday 16 October 2007 20:34:17 Gautham R Shenoy wrote:
> This patch implements a Refcount + Waitqueue based model for
> cpu-hotplug.
Hi Gautham,
I can't see where you re-initialize the completion.
> +static void cpu_hotplug_begin(void)
> +{
> + mutex_lock(&cpu_hotplug.lock);
> + cpu_hotplug.active_writer = current;
> + while (cpu_hotplug.refcount) {
> + mutex_unlock(&cpu_hotplug.lock);
> + wait_for_completion(&cpu_hotplug.readers_done);
> + mutex_lock(&cpu_hotplug.lock);
> + }
AFAICT this will busy-wait on the second CPU hotplug.
Cheers,
Rusty.
next prev parent reply other threads:[~2007-10-17 0:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-16 10:33 [RFC PATCH 0/4] Refcount Based Cpu-Hotplug Revisit Gautham R Shenoy
2007-10-16 10:34 ` [RFC PATCH 1/4] Refcount Based Cpu-Hotplug Implementation Gautham R Shenoy
2007-10-17 0:47 ` Rusty Russell [this message]
2007-10-17 5:37 ` Gautham R Shenoy
2007-10-17 6:29 ` Rusty Russell
2007-10-18 6:29 ` Gautham R Shenoy
2007-10-21 12:47 ` Oleg Nesterov
2007-10-17 10:53 ` Paul Jackson
2007-10-17 11:27 ` Paul Jackson
2007-10-17 11:50 ` Gautham R Shenoy
2007-10-17 12:04 ` Paul Jackson
2007-10-16 10:35 ` [RFC PATCH 2/4] Rename lock_cpu_hotplug to get_online_cpus Gautham R Shenoy
2007-10-17 16:13 ` Nathan Lynch
2007-10-18 7:57 ` Gautham R Shenoy
2007-10-18 8:22 ` Nathan Lynch
2007-10-18 8:59 ` Gautham R Shenoy
2007-10-18 17:30 ` Nathan Lynch
2007-10-19 5:04 ` Gautham R Shenoy
2007-10-22 0:43 ` Nathan Lynch
2007-10-22 4:51 ` Gautham R Shenoy
2007-10-16 10:36 ` [RFC PATCH 3/4] Replace per-subsystem mutexes with get_online_cpus Gautham R Shenoy
2007-10-21 11:39 ` Oleg Nesterov
2007-10-22 4:58 ` Gautham R Shenoy
2007-10-16 10:37 ` [RFC PATCH 4/4] Remove CPU_DEAD/CPU_UP_CANCELLED handling from workqueue.c Gautham R Shenoy
2007-10-17 11:57 ` Oleg Nesterov
2007-10-16 17:20 ` [RFC PATCH 0/4] Refcount Based Cpu-Hotplug Revisit Linus Torvalds
2007-10-17 2:11 ` Dipankar Sarma
2007-10-17 2:23 ` Linus Torvalds
2007-10-17 4:17 ` Gautham R Shenoy
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