On Fri, May 14, 2010 at 08:16:07AM +0530, ratheesh k wrote: > On Fri, May 14, 2010 at 12:13 AM, Sven-Thorsten Dietrich > <thebigcorporation@xxxxxxxxx> wrote: > > > Why would you do this? > I was reading some linux kernel journel about preempt_disable() . This > a doubt came to me . > > > > If you had tried this code, you would have seen the corresponding stack > > dump on the console. > > > Why it so .? could you explain a little more ? .sleep() will schedule > () , which inturn give back control to kernel . Sleeping in the kernel with preemption disabled is considered to be a bug. So the scheduler will print an error and a stack dump when this happens. In contrast, it is OK to do the following: preempt_disable(); do_something(); preempt_enable(); schedule(); preempt_disable(); do_something_else(); preempt_enable(); Thanx, Paul > Thank, > Ratheesh > > On Fri, May 14, 2010 at 12:13 AM, Sven-Thorsten Dietrich > <thebigcorporation@xxxxxxxxx> wrote: > > On Fri, 2010-05-14 at 00:02 +0530, ratheesh k wrote: > >> I am running RT linux . > >> > >> /* code snippet */ > >> > >> preempt_disable() > >> ........... > >> sleep(10); > >> '............ > >> preempt_enable() > >> > >> > >> will this sleep() will cause reschedule ?. > >> > > > > Why would you do this? > > > > If you had tried this code, you would have seen the corresponding stack > > dump on the console. > > > >> if an interrupt comes while premption is disabled , how it is handled ?. > >> > > > > Depends on the number of (idle) cores, the setting of CONFIG_PREEMPT_[] > > and the type of interrupt. > > > > RT threaded IRQs would not run until preemption is enabled on a single > > core system. > > > > > > > >> Thanks, > >> Ratheesh > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
