perf_counter: Change pctrl() behaviour

Instead of en/dis-abling all counters acting on a particular
task, en/dis- able all counters we created.

[ v2: fix crash on first counter enable ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <20090523163012.916937244@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 24 insertions, 63 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 0e97f8961333..4c86a6369764 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1076,79 +1076,26 @@ static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
         __perf_counter_sched_in(ctx, cpuctx, cpu);
 }
 
-int perf_counter_task_disable(void)
+int perf_counter_task_enable(void)
 {
-        struct task_struct *curr = current;
-        struct perf_counter_context *ctx = curr->perf_counter_ctxp;
         struct perf_counter *counter;
-        unsigned long flags;
-
-        if (!ctx || !ctx->nr_counters)
-                return 0;
-
-        local_irq_save(flags);
 
-        __perf_counter_task_sched_out(ctx);
-
-        spin_lock(&ctx->lock);
-
-        /*
-         * Disable all the counters:
-         */
-        perf_disable();
-
-        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
-                if (counter->state != PERF_COUNTER_STATE_ERROR) {
-                        update_group_times(counter);
-                        counter->state = PERF_COUNTER_STATE_OFF;
-                }
-        }
-
-        perf_enable();
-
-        spin_unlock_irqrestore(&ctx->lock, flags);
+        mutex_lock(&current->perf_counter_mutex);
+        list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
+                perf_counter_enable(counter);
+        mutex_unlock(&current->perf_counter_mutex);
 
         return 0;
 }
 
-int perf_counter_task_enable(void)
+int perf_counter_task_disable(void)
 {
-        struct task_struct *curr = current;
-        struct perf_counter_context *ctx = curr->perf_counter_ctxp;
         struct perf_counter *counter;
-        unsigned long flags;
-        int cpu;
-
-        if (!ctx || !ctx->nr_counters)
-                return 0;
-
-        local_irq_save(flags);
-        cpu = smp_processor_id();
-
-        __perf_counter_task_sched_out(ctx);
-
-        spin_lock(&ctx->lock);
 
-        /*
-         * Disable all the counters:
-         */
-        perf_disable();
-
-        list_for_each_entry(counter, &ctx->counter_list, list_entry) {
-                if (counter->state > PERF_COUNTER_STATE_OFF)
-                        continue;
-                counter->state = PERF_COUNTER_STATE_INACTIVE;
-                counter->tstamp_enabled =
-                        ctx->time - counter->total_time_enabled;
-                counter->hw_event.disabled = 0;
-        }
-        perf_enable();
-
-        spin_unlock(&ctx->lock);
-
-        perf_counter_task_sched_in(curr, cpu);
-
-        local_irq_restore(flags);
+        mutex_lock(&current->perf_counter_mutex);
+        list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
+                perf_counter_disable(counter);
+        mutex_unlock(&current->perf_counter_mutex);
 
         return 0;
 }
@@ -1416,6 +1363,11 @@ static int perf_release(struct inode *inode, struct file *file)
         perf_counter_remove_from_context(counter);
         mutex_unlock(&ctx->mutex);
 
+        mutex_lock(&counter->owner->perf_counter_mutex);
+        list_del_init(&counter->owner_entry);
+        mutex_unlock(&counter->owner->perf_counter_mutex);
+        put_task_struct(counter->owner);
+
         free_counter(counter);
         put_context(ctx);
 
@@ -3272,6 +3224,12 @@ SYSCALL_DEFINE5(perf_counter_open,
         perf_install_in_context(ctx, counter, cpu);
         mutex_unlock(&ctx->mutex);
 
+        counter->owner = current;
+        get_task_struct(current);
+        mutex_lock(&current->perf_counter_mutex);
+        list_add_tail(&counter->owner_entry, &current->perf_counter_list);
+        mutex_unlock(&current->perf_counter_mutex);
+
         fput_light(counter_file, fput_needed2);
 
 out_fput:
@@ -3488,6 +3446,9 @@ void perf_counter_init_task(struct task_struct *child)
 
         child->perf_counter_ctxp = NULL;
 
+        mutex_init(&child->perf_counter_mutex);
+        INIT_LIST_HEAD(&child->perf_counter_list);
+
         /*
          * This is executed from the parent task context, so inherit
          * counters that have been marked for cloning.