From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH 01/13] PM: Add wake lock api. Date: Fri, 27 Feb 2009 21:32:52 +0100 Message-ID: <20090227203252.GB1397@ucw.cz> References: <1233802226-23386-1-git-send-email-arve@android.com> <200902131749.57728.u.luckas@road.de> <20090227131807.GA1482@ucw.cz> <200902271507.14747.u.luckas@road.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <200902271507.14747.u.luckas@road.de> 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: Uli Luckas Cc: "swetland@google.com" , linux-pm@lists.linux-foundation.org, "ncunningham@crca.org.au" List-Id: linux-pm@vger.kernel.org On Fri 2009-02-27 15:07:14, Uli Luckas wrote: > On Friday, 27. February 2009, Pavel Machek wrote: > > On Fri 2009-02-13 17:49:57, Uli Luckas wrote: > > > On Friday, 13. February 2009, Matthew Garrett wrote: > > > > Userland ABI would then be a single /dev/inhibit_suspend, > > > > with the counter being bumped each time an application opens it. It'll > > > > automatically be dropped if the application exits without cleaning up. > > > > > > > > This seems simpler and also avoids any arguments about the naming > > > > scheme. What am I missing? > > > > > > Opening and closing an fd sounds like a lot of overhead. Taking and > > > releasing locks if going to be a called with very highg frequency. I'd go > > > for an ioctl. > > > > Ehm? > > > > And introduce nasty interface, and probably slower too since open() is > > time-critical and ioctl() is not? Or do you have benchmarks? > > No, just specualting as open() needs to do a directory lookup. It also needs > to do book keeping. I'd be surprised if open was faster then ioctl. Unless you measure how much slower it is... > On the otherhand if you consider ioctl nasty, maybe write() is an option? You want sleepvetos to be automatically unlocked/freed on close and process exit/kill, so neither write nor ioctl is the right interface. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html