Also, the difference it would make is fix the issue for when a delayed_work is used for both immediate work (mod_delayed_work(0)) and delayed work. On Sun, Mar 16, 2014 at 12:13 PM, dbasehore . <dbasehore@xxxxxxxxxxxx> wrote: > There's already behavior that is somewhat like that with the current > implementation. If there's an item on a workqueue, it could run at any > time. From the perspective of the driver/etc. that is using the > workqueue, there should be no difference between work being on the > workqueue and the kernel triggering a schedule right after the work is > removed from the workqueue, but before the work function has done > anything. > > So to reiterate, calling mod_delayed_work on something that is already > in the workqueue has two behaviors. One, the work is dispatched before > mod_delayed_work can remove it from the workqueue. Two, > mod_delayed_work removes it from the workqueue and sets the timer (or > not in the case of 0). The behavior of the proposed change should be > no different than the first behavior. > > This should not introduce new behavior from the perspective of the > code using delayed_work. It is true that there is a larger window of > time between when you call mod_delayed_work and when an already queued > work item will run, but I don't believe that matters. > > The API will still make sense since we will only ever mod delayed work > but not work that is no longer delayed (on the workqueue). > > On Sun, Mar 16, 2014 at 7:59 AM, Tejun Heo <tj@xxxxxxxxxx> wrote: >> On Sat, Mar 15, 2014 at 01:22:53PM -0700, dbasehore . wrote: >>> mod_delayed_work currently removes a work item from a workqueue if it >>> is on it. Correct me if I'm wrong, but I don't think that this is >>> necessarily required for mod_delayed_work to have the current >>> behavior. We should be able to set the timer while a delayed_work is >>> currently on a workqueue. If the delayed_work is still on the >>> workqueue when the timer goes off, everything is fine. If it has left >>> the workqueue, we can queue it again. >> >> What different would that make w.r.t. this issue? Plus, please note >> that a work item may wait non-insignificant amount of time pending if >> the workqueue is saturated to max_active. Doing the above would make >> mod_delayed_work()'s behavior quite fuzzy - the work item is modified >> or queued to the specified time but if the timer has already expired, >> the work item may execute after unspecified amount of time which may >> be shorter than the new timeout. What kind of interface would that >> be? >> >> Thanks. >> >> -- >> tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>