x86/intel_rdt/mbm: Fix MBM overflow handler during CPU hotplug

When a CPU is dying, the overflow worker is canceled and rescheduled on a
different CPU in the same domain. But if the timer is already about to
expire this essentially doubles the interval which might result in a non
detected overflow.

Cancel the overflow worker and reschedule it immediately on a different CPU
in same domain. The work could be flushed as well, but that would
reschedule it on the same CPU.

[ tglx: Rewrote changelog once again ]

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Link: http://lkml.kernel.org/r/1502845243-20454-2-git-send-email-vikas.shivappa@linux.intel.com

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 97c8d8321e04..b8dc141896b6 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -447,7 +447,7 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
 
 	if (is_mbm_enabled()) {
 		INIT_DELAYED_WORK(&d->mbm_over, mbm_handle_overflow);
-		mbm_setup_overflow_handler(d);
+		mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL);
 	}
 
 	return 0;
@@ -540,7 +540,7 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 	} else if (r == &rdt_resources_all[RDT_RESOURCE_L3] &&
 		   cpu == d->mbm_work_cpu && is_mbm_enabled()) {
 		cancel_delayed_work(&d->mbm_over);
-		mbm_setup_overflow_handler(d);
+		mbm_setup_overflow_handler(d, 0);
 	}
 }