Messages in this thread | | | Date | Wed, 21 Feb 2007 17:30:10 +0300 | From | Oleg Nesterov <> | Subject | Re: [RFC PATCH(Experimental) 2/4] Revert changes to workqueue.c |
| |
On 02/21, Srivatsa Vaddagiri wrote: > > On Tue, Feb 20, 2007 at 11:09:36PM +0300, Oleg Nesterov wrote: > > > Which caller are you referring to here? Maybe we can decide on the > > > option after we see the users of flush_workqueue() in DOWN_PREPARE. > > > > mm/slab.c:cpuup_callback() > > The cancel_rearming_delayed_work, if used as it is in cpuup_callback, > will require that we send DOWN_PREPARE before freeze_processes(). > > But ..I am wondering if we can avoid doing cancel_rearming_delayed_work > (and thus flush_workqueue) in CPU_DOWN_PREPARE of slab.c. Basically, > > mm/slab.c: > > CPU_DOWN_PREPARE: /* All processes frozen now */ > cancel_delayed_work(&per_cpu(reap_work, cpu).timer); > del_work(&per_cpu(reap_work, cpu).work); > break; > > > At the point of CPU_DOWN_PREPARE, keventd should be frozen and hence > del_work() is a matter of just deleting the work from cwq->worklist.
Agreed. Note that we don't need the new "del_work". It is always safe to use cancel_work_sync() if we know that the workqueue is frozen, it won't block. We can also do
if (!cancel_delayed_work()) cancel_work_sync();
but it is ok to do cancel_work_sync() unconditionally.
Oleg.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |