On Mon, Sep 19, 2016 at 05:49:07AM -0400, Mikulas Patocka wrote: > > > On Tue, 13 Sep 2016, Peter Zijlstra wrote: > > > Hi all, > > > > While grepping for PREEMPT_VOLUNTARY I ran into dm_bufio_cond_resched() > > and wondered WTH it was about. > > cond_resched() calls _cond_resched() even if when we have a preemptive > kernel - with preemptive kernel, calling cond_resched is pointless because > rescheduling is done peemtively. > > So, I added that dm_bufio_cond_resched(), that does nothing on peemptive > kernels (and also on PREEMPT_NONE kernels where the user doesn't care > about latency). > > What is the reason why cond_resched() tests for rescheduling with > preemptive kernel? Why should I use cond_resched() in that case? Because every body else does too. 'Fixing' something like that in the dm code is entirely the wrong place. Also, you loose out on the might_sleep() warning implied in it. As it happens, I have a patch fixing that somewhere, let me try and get it merged. But thanks for the reminder, I'll go write a Changelog for this so that people can commit. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
