On Monday 18 January 2010, Oliver Neukum wrote: > Am Montag, 18. Januar 2010 00:00:23 schrieb Rafael J. Wysocki: > > On Sunday 17 January 2010, Benjamin Herrenschmidt wrote: > > > On Sun, 2010-01-17 at 14:27 +0100, Rafael J. Wysocki wrote: > > ... > > > However, it's hard to deal with the case of allocations that have > > > already started waiting for IOs. It might be possible to have some VM > > > hook to make them wakeup, re-evaluate the situation and get out of that > > > code path but in any case it would be tricky. > > > > In the second version of the patch I used an rwsem that made us wait for these > > allocations to complete before we changed gfp_allowed_mask. > > This will be a very, very hot semaphore. What's the impact on performance? rwsems are highly optimized AFAICT, but this is a good question of course. I have no data at the moment. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
