On 10/6/07, Paul Jackson <[EMAIL PROTECTED]> wrote: > > This isn't working for me. > > The key kernel routine for updating a tasks cpus_allowed > cannot be called while holding a spinlock. > > But the above loop holds a spinlock, css_set_lock, between > the cgroup_iter_start and the cgroup_iter_end. > > I end up generating complaints of: > BUG: scheduling while atomic > when I invoke the set_cpus_allowed() above. > > Should css_set_lock be a mutex? Locking changes like that > can be risky.
css_set_lock is an rwlock currently; I'd rather not turn it into an rw mutex since there are places that it gets taken where we can't afford to sleep. > > Or perhaps there should be another callback, called only by > attach() requests back to the same group. Likely cpusets would > be the only subsystem interested in plugging that callback. > > That, or my original patch, which calls the attach routine > even if re-attaching to the current cgroup ... I'd prefer David's solution of grabbing references to tasks during the iteration and then doing set_cpus_allowed outside the tasklist_lock. Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/