On Wed, 19 Mar 2014 20:34:07 +0100 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, Mar 19, 2014 at 03:12:52PM -0400, Steven Rostedt wrote: > > My question to Tejun is, if we create another workqueue, to add the > > rdata->work to, would that prevent the above problem? Or what other > > fixes can we do? > > The way I understand workqueues is that we cannot guarantee concurrency > like this. It tries, but there's no guarantee. > > WQ_MAX_ACTIVE seems to be a hard upper limit of concurrent workers. So > given 511 other blocked works, the described problem will always happen. > > Creating another workqueue doesn't actually create more threads. But I noticed this: Before patch: # ps aux |grep cifs root 3119 0.0 0.0 0 0 ? S< 14:17 0:00 [cifsiod] After patch: # ps aux |grep cifs root 1109 0.0 0.0 0 0 ? S< 15:11 0:00 [cifsiod] root 1111 0.0 0.0 0 0 ? S< 15:11 0:00 [cifsiord] It looks to me that it does create new threads. -- Steve > > There is the kthread_work stuff for if you want a guaranteed worker > thread. -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
