Am Donnerstag, 29. März 2018, 00:19:39 CEST schrieb Joel Fernandes: > Thanks for the quick reply. > > On Wed, Mar 28, 2018 at 6:19 AM, Richard Weinberger <rich...@nod.at> wrote: > > Am Mittwoch, 28. März 2018, 15:11:29 CEST schrieb Geert Uytterhoeven: > >> On Wed, Mar 28, 2018 at 12:28 PM, Joel Fernandes <agnel.j...@gmail.com> > > wrote: > >> > while(release_now == 0); > >> > >> while (release_now == 0) > >> cpu_relax(); > > > > Not sure whether a cpu_relax() fixes the problem. > > I guess the root of the problem is that UML is UP and non-preemptive. > > Therefore the loop is never interrupted. > > To verify I asked for the full source. > > > > cpu_relax actually worked!
Interesting. > Any thoughts on why it helps? Even if its non-preemptive, I did > receive the timer interrupt, so I expected the variable to be set. Timers trigger also with preempt off, I forgot... I think the cpu_relax() issues internally a barrier such that the release_now variable is read again. Can you try barrier() instead of cpu_relax()? I bet it works too. Same if you mark release_now as volatile. Thanks, //richard ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
