From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754790Ab1HJUxa (ORCPT ); Wed, 10 Aug 2011 16:53:30 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:42511 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751720Ab1HJUx3 (ORCPT ); Wed, 10 Aug 2011 16:53:29 -0400 Message-ID: <4E42EFCB.1030005@linaro.org> Date: Wed, 10 Aug 2011 22:53:31 +0200 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110516 Thunderbird/3.1.10 MIME-Version: 1.0 To: Mike Turquette CC: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, gregkh@suse.de, linaro-dev@lists.linaro.org, patches@linaro.org Subject: Re: [PATCH v2 1/2] cpumask: introduce cpumask for hotpluggable CPUs References: <1313006614-28702-1-git-send-email-mturquette@ti.com> <1313006614-28702-2-git-send-email-mturquette@ti.com> In-Reply-To: <1313006614-28702-2-git-send-email-mturquette@ti.com> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/10/2011 10:03 PM, Mike Turquette wrote: > On some platforms it is possible to have some CPUs which support CPU > hotplug and some which do not. Currently the prescence of an 'online' > sysfs entry in userspace is adequate for applications to know that a CPU > supports hotplug, but there is no convenient way to make the same > determination in the kernel. > > To better model this relationship this patch introduces a new cpumask to > track CPUs that support CPU hotplug operations. > > This new cpumask is populated at boot-time and remains static for the > life of the machine. Bits set in the mask indicate a CPU which supports > hotplug, but make no guarantees about whether that CPU is currently > online or not. Likewise a cleared bit in the mask indicates either a > CPU which cannot hotplug or a lack of a populated CPU. > > The purpose of this new cpumask is to aid kernel code which uses CPU to > take CPUs online and offline. Possible uses are as a thermal event > mitigation technique or as a power capping mechanism. > > Signed-off-by: Mike Turquette Reviewed-by: Daniel Lezcano - -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJOQu/KAAoJEAKBbMCpUGYAxnoH/0+WtrRGq0oOjkU8jIxzAEUP OW6S7EQT13v97YapaEwUZpHOzrdeEa9bV5sVI3uc3H9n6dnQbh25eMuhiH/dTwF6 LHV1Tdv7/+ghiSc4NJunpXjAsObezUgTV9n2Zoip3kAfhMdV5DntJu0Izkdb5lkA AD5CqV6oHqC0spa2/nMMeOYsdp3hLP3hA5wCyE8a2rxvbytxl2jRVommXOpF3AnI s3OS7oyVFLpdvxVdAio1cXvM6vILtJFArAqw88AJUBsUsuehRxeOYVvTR3/z4RZD LNEH72IkGY/8OVYp9/VoixWgWTUhXUR5BZwAjCP7a+xQk/1qK1LAM+/CXimwND0= =90gJ -----END PGP SIGNATURE-----