On Thu, May 22, 2014 at 03:50:21PM +0000, Luck, Tony wrote: > >> So I think we can reduce it to just the one rwsem (with recursion) if we > >> shoot CPU_POST_DEAD in the head. > > > > Here's the first bullet. Stressing my box here with Steve's hotplug > > script seems to work fine. > > > > Tony, any objections? > > what was this comment referring to: > > /* intentionally ignoring frozen here */ > > After you move the cmci_rediscover() call, it is now in a place where we are > no longer ignoring frozen (i.e. the old placement did the rediscover even if > the > CPU_TASKS_FROZEN bit was set - with the new placement we will skip > rediscovery. > > So we were working around some interaction between cpu hotplug and frozen. > Do we no longer need to do that?
Hmm, that FROZEN thing is supposedly for hotplug operations while suspend is happening. I guess it makes a little sense to rediscover CMCI banks while suspend is in progress. Whatever. Let's keep it before more crap ensues, that was a good catch, thanks. So, I guess something like that instead. Which means, I'd need to run a couple of suspend/resume rounds while hotplugging cores to see whether we're still kosher. More fun tomorrow. --- From: Borislav Petkov <[email protected]> Date: Thu, 22 May 2014 16:40:54 +0200 Subject: [PATCH] x86, MCE: Kill CPU_POST_DEAD In conjunction with cleaning up CPU hotplug, we want to get rid of CPU_POST_DEAD. Kill this instance here and rediscover CMCI banks at the end of CPU_DEAD. Signed-off-by: Borislav Petkov <[email protected]> --- arch/x86/kernel/cpu/mcheck/mce.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 68317c80de7f..bfde4871848f 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -2391,6 +2391,10 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) threshold_cpu_callback(action, cpu); mce_device_remove(cpu); mce_intel_hcpu_update(cpu); + + /* intentionally ignoring frozen here */ + if (!(action & CPU_TASKS_FROZEN)) + cmci_rediscover(); break; case CPU_DOWN_PREPARE: smp_call_function_single(cpu, mce_disable_cpu, &action, 1); @@ -2402,11 +2406,6 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) break; } - if (action == CPU_POST_DEAD) { - /* intentionally ignoring frozen here */ - cmci_rediscover(); - } - return NOTIFY_OK; } -- 1.9.0 -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" 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.tux.org/lkml/
