trace_workqueue: use percpu data for workqueue stat
Lai Jiangshan [Fri, 16 Jan 2009 08:32:25 +0000 (16:32 +0800)]
Impact: use percpu data instead of a global structure

Use:

   static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);

instead of allocating a global structure.

percpu data also works well on NUMA.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/trace_workqueue.c

index f8118d3..4664990 100644 (file)
@@ -8,6 +8,7 @@
 
 #include <trace/workqueue.h>
 #include <linux/list.h>
+#include <linux/percpu.h>
 #include "trace_stat.h"
 #include "trace.h"
 
@@ -37,7 +38,8 @@ struct workqueue_global_stats {
 /* Don't need a global lock because allocated before the workqueues, and
  * never freed.
  */
-static struct workqueue_global_stats *all_workqueue_stat;
+static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);
+#define workqueue_cpu_stat(cpu) (&per_cpu(all_workqueue_stat, cpu))
 
 /* Insertion of a work */
 static void
@@ -48,8 +50,8 @@ probe_workqueue_insertion(struct task_struct *wq_thread,
        struct cpu_workqueue_stats *node, *next;
        unsigned long flags;
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       list_for_each_entry_safe(node, next, &all_workqueue_stat[cpu].list,
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
                                                        list) {
                if (node->pid == wq_thread->pid) {
                        atomic_inc(&node->inserted);
@@ -58,7 +60,7 @@ probe_workqueue_insertion(struct task_struct *wq_thread,
        }
        pr_debug("trace_workqueue: entry not found\n");
 found:
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 }
 
 /* Execution of a work */
@@ -70,8 +72,8 @@ probe_workqueue_execution(struct task_struct *wq_thread,
        struct cpu_workqueue_stats *node, *next;
        unsigned long flags;
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       list_for_each_entry_safe(node, next, &all_workqueue_stat[cpu].list,
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
                                                        list) {
                if (node->pid == wq_thread->pid) {
                        node->executed++;
@@ -80,7 +82,7 @@ probe_workqueue_execution(struct task_struct *wq_thread,
        }
        pr_debug("trace_workqueue: entry not found\n");
 found:
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 }
 
 /* Creation of a cpu workqueue thread */
@@ -104,11 +106,11 @@ static void probe_workqueue_creation(struct task_struct *wq_thread, int cpu)
 
        cws->pid = wq_thread->pid;
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       if (list_empty(&all_workqueue_stat[cpu].list))
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       if (list_empty(&workqueue_cpu_stat(cpu)->list))
                cws->first_entry = true;
-       list_add_tail(&cws->list, &all_workqueue_stat[cpu].list);
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       list_add_tail(&cws->list, &workqueue_cpu_stat(cpu)->list);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 }
 
 /* Destruction of a cpu workqueue thread */
@@ -119,8 +121,8 @@ static void probe_workqueue_destruction(struct task_struct *wq_thread)
        struct cpu_workqueue_stats *node, *next;
        unsigned long flags;
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       list_for_each_entry_safe(node, next, &all_workqueue_stat[cpu].list,
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
                                                        list) {
                if (node->pid == wq_thread->pid) {
                        list_del(&node->list);
@@ -131,7 +133,7 @@ static void probe_workqueue_destruction(struct task_struct *wq_thread)
 
        pr_debug("trace_workqueue: don't find workqueue to destroy\n");
 found:
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 
 }
 
@@ -141,13 +143,13 @@ static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
        struct cpu_workqueue_stats *ret = NULL;
 
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
 
-       if (!list_empty(&all_workqueue_stat[cpu].list))
-               ret = list_entry(all_workqueue_stat[cpu].list.next,
+       if (!list_empty(&workqueue_cpu_stat(cpu)->list))
+               ret = list_entry(workqueue_cpu_stat(cpu)->list.next,
                                 struct cpu_workqueue_stats, list);
 
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 
        return ret;
 }
@@ -172,9 +174,9 @@ static void *workqueue_stat_next(void *prev, int idx)
        unsigned long flags;
        void *ret = NULL;
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       if (list_is_last(&prev_cws->list, &all_workqueue_stat[cpu].list)) {
-               spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       if (list_is_last(&prev_cws->list, &workqueue_cpu_stat(cpu)->list)) {
+               spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
                for (++cpu ; cpu < num_possible_cpus(); cpu++) {
                        ret = workqueue_stat_start_cpu(cpu);
                        if (ret)
@@ -182,7 +184,7 @@ static void *workqueue_stat_next(void *prev, int idx)
                }
                return NULL;
        }
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 
        return list_entry(prev_cws->list.next, struct cpu_workqueue_stats,
                          list);
@@ -199,10 +201,10 @@ static int workqueue_stat_show(struct seq_file *s, void *p)
                   cws->executed,
                   trace_find_cmdline(cws->pid));
 
-       spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags);
-       if (&cws->list == all_workqueue_stat[cpu].list.next)
+       spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+       if (&cws->list == workqueue_cpu_stat(cpu)->list.next)
                seq_printf(s, "\n");
-       spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags);
+       spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
 
        return 0;
 }
@@ -258,17 +260,9 @@ int __init trace_workqueue_early_init(void)
        if (ret)
                goto no_creation;
 
-       all_workqueue_stat = kmalloc(sizeof(struct workqueue_global_stats)
-                                    * num_possible_cpus(), GFP_KERNEL);
-
-       if (!all_workqueue_stat) {
-               pr_warning("trace_workqueue: not enough memory\n");
-               goto no_creation;
-       }
-
        for_each_possible_cpu(cpu) {
-               spin_lock_init(&all_workqueue_stat[cpu].lock);
-               INIT_LIST_HEAD(&all_workqueue_stat[cpu].list);
+               spin_lock_init(&workqueue_cpu_stat(cpu)->lock);
+               INIT_LIST_HEAD(&workqueue_cpu_stat(cpu)->list);
        }
 
        return 0;