Re: Ordering / preemption of work in a workqueue preempt?
anish singh <[email protected]>
| Newsgroups | gmane.linux.newbie,gmane.linux.kernel.kernelnewbies |
|---|---|
| Message-ID | <CAK7N6voHxx702ZZimdv=18Z_Rxgaw9YJMRHC=CqGEKEmrJzEKw@mail.gmail.com> |
On Fri, Nov 15, 2013 at 5:01 PM, Rajat Sharma <[email protected]> wrote: > Hi Rajat, > > > On Fri, Nov 15, 2013 at 7:16 AM, Rajat Jain <[email protected]> wrote: >> >> Hi, >> >> I have a single work queue, on which I have scheduled a worker function >> [using queue_work(wq, fn)] in interrupt context. >> >> I get the interrupt twice before the work queue gets a chance to run, and >> hence the same function will get queued twice (with different private >> context - arguments etc) which is fine and expected. >> >> Questions: >> >> 1) Is it possible that the instance that was queued by 2nd interrupt, can >> get to run BEFORE the instance that was queued by 1st interrupt? In other >> words, is reordering possible? use alloc_ordered_workqueue: only one workqueue will be active at a time and it will execute in the queued sequence. > > > It is unlikely as workqueue would have internal queing of tasks. > >> >> >> 2) Is it possible that one running instance of the function, can get >> preempted by second instance of the same work queue? I read through >> http://lwn.net/Articles/511421/ and it talks about same work queue cannot >> run on different CPU, but I have doubt about single CPU. If If I am writing >> a worker function, does my code have to be ready that it can be preempted by >> another instance of the same function? >> > > Do you mean the system has just one CPU, then there would be just one worker > thread in the workqueue which will pick up requests one by one. Do you see > multiple threads? > >> >> Please note that I understand that my worker function can preempted by >> other processes, my doubts are related to the same workqueue. >> >> Thanks, >> >> Rajat >> >> > > Rajat > >> >> _______________________________________________ >> Kernelnewbies mailing list >> [email protected] >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > _______________________________________________ > Kernelnewbies mailing list > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > -- To unsubscribe from this list: send the line "unsubscribe linux-newbie" 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.linux-learn.org/faqs