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 13:00:04 -0700 Message-ID: <20100513200003.GE3428@atomide.com> References: <20100513191717.GA3428@atomide.com> <20100513192522.GA19256@srcf.ucam.org> <20100513194205.GC3428@atomide.com> <20100513195349.GB19722@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100513195349.GB19722@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 12:49]: > On Thu, May 13, 2010 at 12:42:05PM -0700, Tony Lindgren wrote: > > > 1. In the kernel, we add one more timer queue for critical timers. > > The current timer queue(s) stay as it is. > > > > 2. We allow selecting the timer based on some flag, the default > > behaviour being the current default timer queue. > > > > 3. Then we add next_timer_interupt_critical() to only query the > > critical timers along the lines of the current next_timer_interrupt(). > > > > 4. We implement a custom pm_idle that suspends the system based on > > some logic and checking if next_timer_interrupt_critical() is > > empty. If the next_timer_interrupt_critical() does not return > > anything, we assume it's OK to suspend the system. > > Ok. So we stick the untrusted bits of userspace on the critical timer > list. I guess you mean the trusted instead of untrusted apps in the userspace above, the ones that are critical to keep running. > Now we get a network packet that generates a wakeup event and gets > read by an application. What happens if that application can't fully > process the packet in a single timeslice? 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. Regards, Tony