On Thu, Jan 21, 2016 at 11:21:30AM +0100, Michal Hocko wrote: > [CCing Rafael - the thread starts here > http://lkml.kernel.org/r/1452661968-11482-1-git-send-email-david%40fromorbit.com] > > On Thu 21-01-16 08:19:44, Dave Chinner wrote: > > On Wed, Jan 20, 2016 at 09:47:50AM +0100, Michal Hocko wrote: > > > On Wed 13-01-16 16:12:48, Dave Chinner wrote: > > > > This reverts commit 24ba16bb3d499c49974669cd8429c3e4138ab102 as it > > > > prevents machines from suspending. This regression occurs when the > > > > xfsaild is idle on entry to suspend, and so there s no activity to > > > > wake it from it's idle sleep and hence see that it is supposed to > > > > freeze. Hence the freezer times out waiting for it and suspend is > > > > cancelled. > > > > > > > > There is no obvious fix for this short of freezing the filesystem > > > > properly, so revert this change for now. > > > > > > We had a similar report opensuse bugzilla just recently. I believe the > > > proper fix should be the following: > > .... > > > diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c > > > index aa67339b9537..d6c9c3e9e02b 100644 > > > --- a/fs/xfs/xfs_trans_ail.c > > > +++ b/fs/xfs/xfs_trans_ail.c > > > @@ -520,14 +520,14 @@ xfsaild( > > > if (!xfs_ail_min(ailp) && > > > ailp->xa_target == ailp->xa_target_prev) { > > > spin_unlock(&ailp->xa_lock); > > > - schedule(); > > > + freezable_schedule(); > > > > Oh, wonderful. A completely separate set of undocumented schedule > > functions defined inside the freezer header files that are needed > > just for freezable kthreads. > > Yeah, I am not really happy about them either. > > > Perhaps there should be some documentation somewhere on how to write > > suspend safe kthreads? > > There is something in Documentation/power/freezing-of-tasks.txt but > freezable_schedule* is not mentioned there. Prhaps something like the > following would make it more clear? When I did "git grep freezable_schedule" nothing showed up in the Documentation directory. I'd suggest that the entire API needs reference in Documentation/scheduler (i.e. all the freezable_schedule_timeout variants, the wait_event stuff, etc) as well as in the freezer documentation so that git grep finds them in the appropriate places.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
