From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 3/9] PM: suspend_block: Abort task freezing if a suspend_blocker is active. Date: Sat, 9 May 2009 01:01:01 +0200 Message-ID: <200905090101.02390.rjw@sisk.pl> References: <1241583529-5092-1-git-send-email-arve@android.com> <200905081640.44894.rjw@sisk.pl> <1241821626.19600.325.camel@nigel-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1241821626.19600.325.camel@nigel-laptop> Content-Disposition: inline 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: Nigel Cunningham Cc: u.luckas@road.de, swetland@google.com, linux-pm@lists.linux-foundation.org List-Id: linux-pm@vger.kernel.org On Saturday 09 May 2009, Nigel Cunningham wrote: > Hi. > > On Fri, 2009-05-08 at 16:40 +0200, Rafael J. Wysocki wrote: > > The timeout is actually a workaround for the problem that we don't > > really > > know if tasks are going to react to our freeze requests and how much time it is > > going to take. The current value of 20 s was chosen after a number of > > experiments showing that in some cases the freezing _was_ going to take so > > much time. Of course the question is whether it makes sense to give up earlier > > even if tasks would eventually freeze, but that's a different issue. > > What were the circumstances in which freezing could take 20s? Compiling the kernel with "make -j" on a dual core system IIRC. Generally, the situation in which there are many runnable tasks and new tasks come and go etc. I haven't repeated this benchmark recently, though, so it's probably worth doing again. Which has a little to do with the $subject patch IMO, because I think that it's reasonable to stop freezing tasks as soon as we know that it won't be necessary anyway. Thanks, Rafael