On Friday, 27. February 2009, Pavel Machek wrote: > 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... > OK. Opening /dev/null 100000 times readonly takes 365 ms on my machine. Opening it once and then, 100000 times writing 1 byte takes 32 ms. Why exactly did you think I had to provide numbers??? > > 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. An application opens a device node and then writes 1s to take the lock and 0s to release it. Why does that make it impossible to auto-release the lock on close? Uli -- ------- ROAD ...the handyPC Company - - - ) ) ) Uli Luckas Head of Software Development ROAD GmbH Bennigsenstr. 14 | 12159 Berlin | Germany fon: +49 (30) 230069 - 62 | fax: +49 (30) 230069 - 69 url: www.road.de Amtsgericht Charlottenburg: HRB 96688 B Managing director: Hans-Peter Constien _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
