On Wed, Apr 23, 2014 at 12:35:50PM -0700, Andrew Morton wrote: > On Wed, 23 Apr 2014 15:22:28 -0400 Don Zickus <dzickus@xxxxxxxxxx> wrote: > > > On Tue, Apr 22, 2014 at 11:28:28AM -0700, Andrew Morton wrote: > > > On Tue, 22 Apr 2014 11:17:24 -0400 Don Zickus <dzickus@xxxxxxxxxx> wrote: > > > > > > > Added more patches to handle the 'uniprocessor' panic case by sending NMIs > > > > to every cpu but self. Only affects x86, sparc. > > > > > > > > > > Looks OK to me. A couple of things: > > > > > > - Patches 1-3 should be combined so we don't create bisection holes > > > due to x86 and sparc build errors. > > > > > > - Patch 4 adds stuff which is unusable on uniprocessor, especially > > > the presence of /proc/sys/kernel/softlockup_all_cpu_backtrace. We > > > already have #ifdef CONFIG_SMP in kern_table, so do more of that? > > > > Are you suggesting just add CONFIG_SMP to kern_table entry or all the > > pieces in kernel/watchdog.c too? I wasn't sure how messy I should make > > this patch. > > Well, don't go nuts and be tasteful. > > /proc/sys/kernel/softlockup_all_cpu_backtrace should disappear. > > Look around for existing #ifdef CONFIG_SMP blocks to use. > > Making sysctl_softlockup_all_cpu_backtrace evaluate to literal zero > will cause the compiler to remove unused code without ifdefs. This > might require that watchdog_timer_fn:softlockup_all_cpu_backtrace (why > does this local exist btw) be declared const - check the compiler The local exists because it was pointed out in a private review that there could be a race in which the sysctl value might change in the middle of the execution of a softlockup. This would result in a permanently disable softlockup_all_cpu_backtrace because the flag would never be cleared. Hence the snapshot of the local copy to prevent that race. I posted an update of the patchset. Cheers, Don -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
