Re: [RFC PATCH 1/4] Refcount Based Cpu-Hotplug Implementation

From: Rusty Russell
Date: Tue Oct 16 2007 - 20:48:19 EST


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.
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