perf: Dynamic pmu types

Extend the perf_pmu_register() interface to allow for named and
dynamic pmu types.

Because we need to support the existing static types we cannot use
dynamic types for everything, hence provide a type argument.

If we want to enumerate the PMUs they need a name, provide one.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101117222056.259707703@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 42 insertions, 6 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index a3d568fbacc6..8f09bc877a30 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -13,6 +13,7 @@
 #include <linux/mm.h>
 #include <linux/cpu.h>
 #include <linux/smp.h>
+#include <linux/idr.h>
 #include <linux/file.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
@@ -4961,7 +4962,7 @@ static struct pmu perf_tracepoint = {
 
 static inline void perf_tp_register(void)
 {
-        perf_pmu_register(&perf_tracepoint);
+        perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
 }
 
 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
@@ -5305,8 +5306,9 @@ static void free_pmu_context(struct pmu *pmu)
 out:
         mutex_unlock(&pmus_lock);
 }
+static struct idr pmu_idr;
 
-int perf_pmu_register(struct pmu *pmu)
+int perf_pmu_register(struct pmu *pmu, char *name, int type)
 {
         int cpu, ret;
 
@@ -5316,13 +5318,32 @@ int perf_pmu_register(struct pmu *pmu)
         if (!pmu->pmu_disable_count)
                 goto unlock;
 
+        pmu->type = -1;
+        if (!name)
+                goto skip_type;
+        pmu->name = name;
+
+        if (type < 0) {
+                int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
+                if (!err)
+                        goto free_pdc;
+
+                err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
+                if (err) {
+                        ret = err;
+                        goto free_pdc;
+                }
+        }
+        pmu->type = type;
+
+skip_type:
         pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
         if (pmu->pmu_cpu_context)
                 goto got_cpu_context;
 
         pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
         if (!pmu->pmu_cpu_context)
-                goto free_pdc;
+                goto free_ird;
 
         for_each_possible_cpu(cpu) {
                 struct perf_cpu_context *cpuctx;
@@ -5366,6 +5387,10 @@ unlock:
 
         return ret;
 
+free_idr:
+        if (pmu->type >= PERF_TYPE_MAX)
+                idr_remove(&pmu_idr, pmu->type);
+
 free_pdc:
         free_percpu(pmu->pmu_disable_count);
         goto unlock;
@@ -5385,6 +5410,8 @@ void perf_pmu_unregister(struct pmu *pmu)
         synchronize_rcu();
 
         free_percpu(pmu->pmu_disable_count);
+        if (pmu->type >= PERF_TYPE_MAX)
+                idr_remove(&pmu_idr, pmu->type);
         free_pmu_context(pmu);
 }
 
@@ -5394,6 +5421,13 @@ struct pmu *perf_init_event(struct perf_event *event)
         int idx;
 
         idx = srcu_read_lock(&pmus_srcu);
+
+        rcu_read_lock();
+        pmu = idr_find(&pmu_idr, event->attr.type);
+        rcu_read_unlock();
+        if (pmu)
+                goto unlock;
+
         list_for_each_entry_rcu(pmu, &pmus, entry) {
                 int ret = pmu->event_init(event);
                 if (!ret)
@@ -6555,11 +6589,13 @@ void __init perf_event_init(void)
 {
         int ret;
 
+        idr_init(&pmu_idr);
+
         perf_event_init_all_cpus();
         init_srcu_struct(&pmus_srcu);
-        perf_pmu_register(&perf_swevent);
-        perf_pmu_register(&perf_cpu_clock);
-        perf_pmu_register(&perf_task_clock);
+        perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
+        perf_pmu_register(&perf_cpu_clock, NULL, -1);
+        perf_pmu_register(&perf_task_clock, NULL, -1);
         perf_tp_register();
         perf_cpu_notifier(perf_cpu_notify);
         register_reboot_notifier(&perf_reboot_notifier);