On 04/20, Jarek Poplawski wrote: > > On Thu, Apr 19, 2007 at 02:21:22PM +0400, Oleg Nesterov wrote: > ... > > Yes. It would be better to use cancel_work_sync() instead of > > flush_workqueue() > > to make this less possible (because cancel_work_sync() doesn't need to wait > > for > > the whole ->worklist), but we can't. > > > > > Maybe this patch could check, if I'm not dreaming... > > > > Also: cancel_rearming_delayed_work() will hang if it (or > > cancel_delayed_work()) > > was already called. > > > > I had some ideas how to make this interface reliable, but I can't see how > > to do > > this without uglification of the current code. > > For some time I thought about using a flag (isn't there > one available after NOAUTOREL?), e.g. WORK_STRUCT_CANCEL, > as a sign: > > - for a workqueue code: that the work shouldn't be queued, > nor executed, if possiblei, at first possible check.
Well, yes and no, afaics. (note also that NOAUTOREL has already gone). First, this flag should be cleared after return from cancel_rearming_delayed_work(). Also, we should add a lot of nasty checks to workqueue.c I _think_ we can re-use WORK_STRUCT_PENDING to improve this interface. Note that if we set WORK_STRUCT_PENDING, the work can't be queued, and dwork->timer can't be started. The only problem is that it is not so trivial to avoid races. I'll try to do something on Sunday. > - for a work function: to stop execution as soon as possible, > even without completing the usual job, at first possible check. I doubt we need this "in general". It is easy to add some flag to the work_struct's container and check it in work->func() when needed. Oleg. - 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/
