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
mariux64 · Aug 16, 2017 · bbc4615 · bbc4615
1 parent a9110b5
commit bbc4615
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Showing 4 changed files with 6 additions and 6 deletions.
diff --git 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);
 	}
 }
 

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
@@ -422,7 +422,7 @@ void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 				    struct rdt_domain *d);
 void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
 		    struct rdtgroup *rdtgrp, int evtid, int first);
-void mbm_setup_overflow_handler(struct rdt_domain *dom);
+void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms);
 void mbm_handle_overflow(struct work_struct *work);
 
 #endif /* _ASM_X86_INTEL_RDT_H */
diff --git a/arch/x86/kernel/cpu/intel_rdt_monitor.c b/arch/x86/kernel/cpu/intel_rdt_monitor.c
@@ -417,9 +417,9 @@ void mbm_handle_overflow(struct work_struct *work)
 	mutex_unlock(&rdtgroup_mutex);
 }
 
-void mbm_setup_overflow_handler(struct rdt_domain *dom)
+void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms)
 {
-	unsigned long delay = msecs_to_jiffies(MBM_OVERFLOW_INTERVAL);
+	unsigned long delay = msecs_to_jiffies(delay_ms);
 	int cpu;
 
 	if (!static_branch_likely(&rdt_enable_key))

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1140,7 +1140,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
 	if (is_mbm_enabled()) {
 		r = &rdt_resources_all[RDT_RESOURCE_L3];
 		list_for_each_entry(dom, &r->domains, list)
-			mbm_setup_overflow_handler(dom);
+			mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL);
 	}
 
 	goto out;