On Tue, 2010-12-21 at 10:34 +0530, Bharata B Rao wrote: > On Mon, Dec 20, 2010 at 10:09 PM, Mike Galbraith <efault@xxxxxx> wrote: > > On Mon, 2010-12-20 at 21:16 +0530, Bharata B Rao wrote: > >> On Mon, Dec 20, 2010 at 6:49 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote: > >> > On Mon, 2010-12-20 at 18:38 +0530, Bharata B Rao wrote: > >> >> The autogroup patchset removes the display of cgroup name from > >> >> sched_debug output. > >> > > >> > Hrmph.. that wasn't supposed to happen, care to send a patch to fix that > >> > up? > >> > >> There are two aspects here: > >> > >> - Printing cgroup name for per-CPU cfs_rqs shouldn't be affected by > >> autogroup and the old code should work here. > >> - Printing cgroup name for tasks depends on task_group(), which has > >> been changed by autogroup patch. I haven't really looked deep into > >> autogroup patch, but from whatever I can gather, Mike had a reason > >> to remove this bit from sched_debug. The task groups created for > >> autogroups don't have cgroups associated with them and hence no > >> dentries and hence no pathnames. > > > > Mike didn't remove it, but _was_ supposed to get around to it. > > > >> I guess we could do fix this as shown in the attached patch. > > > > > > +#ifdef CONFIG_CGROUP_SCHED > > + { > > + char path[64]; > > + > > > > ... > > > > +#if defined(CONFIG_CGROUP_SCHED) && defined(CONFIG_FAIR_GROUP_SCHED) > > + char path[128]; > > > > > > One reason it was removed was path[64/128]. > > Other callers of cgroup_path use PATH_MAX=4096 here. I believe the > original reason for these short path sizes was to be light on stack > and as well as to avoid allocation. Can we have some reasonable length > (256 or 512 ?) and live with truncation (if that ever happens) ? I don't see why not, unlikely situation in non-critical path. > Also, while displaying group name with tasks, does it make sense to > display autogroup-<id> (the one shown in /proc/<pid>/autogroup) ? I did to me obviously :) I'm fine with it not showing up, though if it survives and evolves, maybe it'll want visibility. ATM, you know what's in what group via ps -o foo,session. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html