From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 6) Date: Thu, 13 May 2010 13:23:20 -0700 Message-ID: <20100513202320.GF3428@atomide.com> References: <20100513191717.GA3428@atomide.com> <20100513192522.GA19256@srcf.ucam.org> <20100513194205.GC3428@atomide.com> <20100513195349.GB19722@srcf.ucam.org> <20100513200003.GE3428@atomide.com> <20100513200814.GA20254@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100513200814.GA20254@srcf.ucam.org> Sender: linux-kernel-owner@vger.kernel.org To: Matthew Garrett Cc: Alan Stern , Paul Walmsley , Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= , Linux-pm mailing list , Kernel development list , Tejun Heo , Oleg Nesterov , Kevin Hilman , magnus.damm@gmail.com, Theodore Ts'o , mark gross , Arjan van de Ven , Geoff Smith , Brian Swetland , "Rafael J. Wysocki" , =?utf-8?Q?Beno=C3=AEt?= Cousson , linux-omap@vger.kernel.org, Vitaly Wool , Mark Brown , Liam Girdwood List-Id: linux-omap@vger.kernel.org * Matthew Garrett [100513 13:03]: > On Thu, May 13, 2010 at 01:00:04PM -0700, Tony Lindgren wrote: > > > The system stays running because there's something to do. The system > > won't suspend until all the processors hit the kernel idle loop and > > the next_timer_interrupt_critical() returns nothing. > > At which point an application in a busy loop cripples you. Maybe you could deal with the misbehaving untrusted apps in the userspace by sending kill -STOP to them when the screen blanks? Then continue when some event wakes up the system again. > I think we could implement your suggestion more easily by just giving > untrusted applications an effectively infinite amount of timer slack, > but it still doesn't handle the case where an app behaves excrutiatingly > badly. Hmm, if you use timer slack then you still need to search through the whole timer list instead of a smaller critical timer list. Both ways sound doable though. Regards, Tony