From: Peter Zijlstra <peterz@infradead.org>
To: Mike Turquette <mturquette@ti.com>
Cc: linux-kernel@vger.kernel.org,
linux-pm@lists.linux-foundation.org, linaro-dev@lists.linaro.org,
patches@linaro.org, gregkh@suse.de
Subject: Re: [PATCH v2 0/2] new cpumask for hotpluggable CPUs
Date: Thu, 11 Aug 2011 20:30:23 +0200 [thread overview]
Message-ID: <1313087423.8491.11.camel@twins> (raw)
In-Reply-To: <1313006614-28702-1-git-send-email-mturquette@ti.com>
On Wed, 2011-08-10 at 13:03 -0700, Mike Turquette wrote:
> This patch series introduces a new cpumask which tracks CPUs that
> support hotplugging. The purpose of this patch series is to provide a
> simple method for kernel code to know which CPUs can be hotplugged and
> which ones cannot. Potential users of this code might be a thermal
> mitigation technique which uses hotplug to lower temperature, or a power
> capping mechanism which uses hotplug to lower power consumption.
>
> All the of usual cpumask helper functions are created for this new mask.
> The second patch in this series simply sets the bit for elligible CPUs
> while they are being registered. The cpumask itself is static after
> boot and should not change (like the possbile mask).
I still most strongly object to people using hotplug for these goals.
Why do you need to go through the entire dance of hotplug just to idle a
cpu? Hotplug not only idles the cpu but tears down (and rebuilds) an
insane amount of resources associated with the cpu.
Nacked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
next prev parent reply other threads:[~2011-08-11 18:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-10 20:03 [PATCH v2 0/2] new cpumask for hotpluggable CPUs Mike Turquette
2011-08-10 20:03 ` [PATCH v2 1/2] cpumask: introduce " Mike Turquette
2011-08-10 20:53 ` Daniel Lezcano
2011-08-11 6:06 ` Amit Kucheria
2011-08-11 18:39 ` Turquette, Mike
2011-08-10 20:03 ` [PATCH v2 2/2] cpu: update cpu_hotpluggable_mask in register_cpu Mike Turquette
2011-08-10 20:54 ` Daniel Lezcano
2011-08-11 18:30 ` Peter Zijlstra [this message]
2011-08-11 19:25 ` [PATCH v2 0/2] new cpumask for hotpluggable CPUs Turquette, Mike
2011-08-11 19:38 ` Peter Zijlstra
2011-08-11 19:54 ` [PATCH v3 1/2] cpumask: introduce " Mike Turquette
2011-08-11 19:54 ` [PATCH v3 2/2] cpu: update cpu_hotpluggable_mask in register_cpu Mike Turquette
2011-08-11 20:02 ` [PATCH v3 1/2] cpumask: introduce cpumask for hotpluggable CPUs Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1313087423.8491.11.camel@twins \
--to=peterz@infradead.org \
--cc=gregkh@suse.de \
--cc=linaro-dev@lists.linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@lists.linux-foundation.org \
--cc=mturquette@ti.com \
--cc=patches@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox