[PATCH] powerpc: get rid of per_cpu EEH counters

242-eeh-no-percpu-counters.patch

Remove per-cpu counters from the EEH code.  These statistics counters
are incremented at a very low frequency, and the performance gains of
per-cpu variables are negligable.  By contrast, the counters weren't
safe against cpu off/online operations, and its not worth the effort
to make them so (other than to turn them into plain globals).

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
(cherry picked from be3b5d1be053ccb41e91fa5a6f43ef5db301357d commit)

arch/powerpc/platforms/pseries/eeh.c

@@ -97,14 +97,14 @@ static DEFINE_SPINLOCK(slot_errbuf_lock);
 static int eeh_error_buf_size;
 
 /* System monitoring statistics */
-static DEFINE_PER_CPU(unsigned long, no_device);
-static DEFINE_PER_CPU(unsigned long, no_dn);
-static DEFINE_PER_CPU(unsigned long, no_cfg_addr);
-static DEFINE_PER_CPU(unsigned long, ignored_check);
-static DEFINE_PER_CPU(unsigned long, total_mmio_ffs);
-static DEFINE_PER_CPU(unsigned long, false_positives);
-static DEFINE_PER_CPU(unsigned long, ignored_failures);
-static DEFINE_PER_CPU(unsigned long, slot_resets);
+static unsigned long no_device;
+static unsigned long no_dn;
+static unsigned long no_cfg_addr;
+static unsigned long ignored_check;
+static unsigned long total_mmio_ffs;
+static unsigned long false_positives;
+static unsigned long ignored_failures;
+static unsigned long slot_resets;
 
 #define IS_BRIDGE(class_code) (((class_code)<<16) == PCI_BASE_CLASS_BRIDGE)
 
@@ -288,13 +288,13 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	enum pci_channel_state state;
 	int rc = 0;
 
-	__get_cpu_var(total_mmio_ffs)++;
+	total_mmio_ffs++;
 
 	if (!eeh_subsystem_enabled)
 		return 0;
 
 	if (!dn) {
-		__get_cpu_var(no_dn)++;
+		no_dn++;
 		return 0;
 	}
 	pdn = PCI_DN(dn);
@@ -302,7 +302,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	/* Access to IO BARs might get this far and still not want checking. */
 	if (!(pdn->eeh_mode & EEH_MODE_SUPPORTED) ||
 	    pdn->eeh_mode & EEH_MODE_NOCHECK) {
-		__get_cpu_var(ignored_check)++;
+		ignored_check++;
 #ifdef DEBUG
 		printk ("EEH:ignored check (%x) for %s %s\n", 
 		        pdn->eeh_mode, pci_name (dev), dn->full_name);
@@ -311,7 +311,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	}
 
 	if (!pdn->eeh_config_addr && !pdn->eeh_pe_config_addr) {
-		__get_cpu_var(no_cfg_addr)++;
+		no_cfg_addr++;
 		return 0;
 	}
 
@@ -353,7 +353,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	if (ret != 0) {
 		printk(KERN_WARNING "EEH: read_slot_reset_state() failed; rc=%d dn=%s\n",
 		       ret, dn->full_name);
-		__get_cpu_var(false_positives)++;
+		false_positives++;
 		rc = 0;
 		goto dn_unlock;
 	}
@@ -362,14 +362,14 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	if (rets[1] != 1) {
 		printk(KERN_WARNING "EEH: event on unsupported device, rc=%d dn=%s\n",
 		       ret, dn->full_name);
-		__get_cpu_var(false_positives)++;
+		false_positives++;
 		rc = 0;
 		goto dn_unlock;
 	}
 
 	/* If not the kind of error we know about, punt. */
 	if (rets[0] != 2 && rets[0] != 4 && rets[0] != 5) {
-		__get_cpu_var(false_positives)++;
+		false_positives++;
 		rc = 0;
 		goto dn_unlock;
 	}
@@ -377,12 +377,12 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
 	/* Note that config-io to empty slots may fail;
 	 * we recognize empty because they don't have children. */
 	if ((rets[0] == 5) && (dn->child == NULL)) {
-		__get_cpu_var(false_positives)++;
+		false_positives++;
 		rc = 0;
 		goto dn_unlock;
 	}
 
-	__get_cpu_var(slot_resets)++;
+	slot_resets++;
  
 	/* Avoid repeated reports of this failure, including problems
 	 * with other functions on this device, and functions under
@@ -432,7 +432,7 @@ unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned lon
 	addr = eeh_token_to_phys((unsigned long __force) token);
 	dev = pci_get_device_by_addr(addr);
 	if (!dev) {
-		__get_cpu_var(no_device)++;
+		no_device++;
 		return val;
 	}
 
@@ -963,25 +963,9 @@ EXPORT_SYMBOL_GPL(eeh_remove_bus_device);
 
 static int proc_eeh_show(struct seq_file *m, void *v)
 {
-	unsigned int cpu;
-	unsigned long ffs = 0, positives = 0, failures = 0;
-	unsigned long resets = 0;
-	unsigned long no_dev = 0, no_dn = 0, no_cfg = 0, no_check = 0;
-
-	for_each_cpu(cpu) {
-		ffs += per_cpu(total_mmio_ffs, cpu);
-		positives += per_cpu(false_positives, cpu);
-		failures += per_cpu(ignored_failures, cpu);
-		resets += per_cpu(slot_resets, cpu);
-		no_dev += per_cpu(no_device, cpu);
-		no_dn += per_cpu(no_dn, cpu);
-		no_cfg += per_cpu(no_cfg_addr, cpu);
-		no_check += per_cpu(ignored_check, cpu);
-	}
-
 	if (0 == eeh_subsystem_enabled) {
 		seq_printf(m, "EEH Subsystem is globally disabled\n");
-		seq_printf(m, "eeh_total_mmio_ffs=%ld\n", ffs);
+		seq_printf(m, "eeh_total_mmio_ffs=%ld\n", total_mmio_ffs);
 	} else {
 		seq_printf(m, "EEH Subsystem is enabled\n");
 		seq_printf(m,
@@ -993,8 +977,10 @@ static int proc_eeh_show(struct seq_file *m, void *v)
 				"eeh_false_positives=%ld\n"
 				"eeh_ignored_failures=%ld\n"
 				"eeh_slot_resets=%ld\n",
-				no_dev, no_dn, no_cfg, no_check,
-				ffs, positives, failures, resets);
+				no_device, no_dn, no_cfg_addr, 
+				ignored_check, total_mmio_ffs, 
+				false_positives, ignored_failures, 
+				slot_resets);
 	}
 
 	return 0;