From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [PATCH 0/8] Suspend block api (version 6) Date: Mon, 17 May 2010 22:06:15 +0100 Message-ID: <20100517210615.GB1873@srcf.ucam.org> References: <87wrvl5479.fsf@deeprootsystems.com> <20100503215028.GB18910@srcf.ucam.org> <20100514203202.GA12409@srcf.ucam.org> <87aas2azc5.fsf@deeprootsystems.com> <20100514231510.GG16989@thunk.org> <87r5laa4oc.fsf@deeprootsystems.com> <20100517193440.GA32066@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Linus WALLEIJ Cc: Greg Kroah-Hartman , Jesse Barnes , Oleg Nesterov , "linux-pm@lists.linux-foundation.org" , Arjan van de Ven , Len Brown , Jacob Pan , "linux-omap@vger.kernel.org" , Liam Girdwood , Daniel Walker , "tytso@mit.edu" , Geoff Smith , Brian Swetland , Mark Brown , "linux-kernel@vger.kernel.org" , Tejun Heo , Andrew Morton , Wu Fengguang List-Id: linux-omap@vger.kernel.org On Mon, May 17, 2010 at 10:53:36PM +0200, Linus WALLEIJ wrote: > I understand the problem such that the scheduler cannot determine whether > a certain process should be allowed to schedule or not. > = > It strikes me that the intuitive solution is to group all un-trusted = > processes/threads/tasks that need to be shut off even if they are > scheduling into a control group and let the idle code ignore the > processes in this group. > = > Or is there something too na=EFve about this? It gets most of the way there (and I spent a while playing with it), but = the problem is that not all wakeup events get proxied through the = trusted userspace runtime. Network packets are the easiest example - a = packet may wake the system, but if the process it's delivered to is = frozen then obviously things get trickier. It's also racy, in that if = you're currently awake and receive a packet that would otherwise have = woken the system you may go to sleep between the packet being received = and bubbling up through the kernel to get to userspace. -- = Matthew Garrett | mjg59@srcf.ucam.org