perf counters: hw driver API
Impact: restructure code, introduce hw_ops driver abstraction
Introduce this abstraction to handle counter details:
struct hw_perf_counter_ops {
void (*hw_perf_counter_enable) (struct perf_counter *counter);
void (*hw_perf_counter_disable) (struct perf_counter *counter);
void (*hw_perf_counter_read) (struct perf_counter *counter);
};
This will be useful to support assymetric hw details, and it will also
be useful to implement "software counters". (Counters that count kernel
managed sw events such as pagefaults, context-switches, wall-clock time
or task-local time.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 278209c5..e6e41ca 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -37,18 +37,15 @@
/*
* Architecture provided APIs - weak aliases:
*/
-
-int __weak hw_perf_counter_init(struct perf_counter *counter)
+extern __weak struct hw_perf_counter_ops *
+hw_perf_counter_init(struct perf_counter *counter)
{
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
}
-void __weak hw_perf_counter_enable(struct perf_counter *counter) { }
-void __weak hw_perf_counter_disable(struct perf_counter *counter) { }
-void __weak hw_perf_counter_read(struct perf_counter *counter) { }
-void __weak hw_perf_disable_all(void) { }
-void __weak hw_perf_enable_all(void) { }
-void __weak hw_perf_counter_setup(void) { }
+void __weak hw_perf_disable_all(void) { }
+void __weak hw_perf_enable_all(void) { }
+void __weak hw_perf_counter_setup(void) { }
#if BITS_PER_LONG == 64
@@ -146,7 +143,7 @@
spin_lock(&ctx->lock);
if (counter->active) {
- hw_perf_counter_disable(counter);
+ counter->hw_ops->hw_perf_counter_disable(counter);
counter->active = 0;
ctx->nr_active--;
cpuctx->active_oncpu--;
@@ -257,7 +254,7 @@
ctx->nr_counters++;
if (cpuctx->active_oncpu < perf_max_counters) {
- hw_perf_counter_enable(counter);
+ counter->hw_ops->hw_perf_counter_enable(counter);
counter->active = 1;
counter->oncpu = cpu;
ctx->nr_active++;
@@ -333,7 +330,7 @@
if (!counter->active)
return;
- hw_perf_counter_disable(counter);
+ counter->hw_ops->hw_perf_counter_disable(counter);
counter->active = 0;
counter->oncpu = -1;
@@ -392,7 +389,7 @@
struct perf_counter_context *ctx,
int cpu)
{
- hw_perf_counter_enable(counter);
+ counter->hw_ops->hw_perf_counter_enable(counter);
counter->active = 1;
counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
@@ -509,7 +506,9 @@
*/
static void __hw_perf_counter_read(void *info)
{
- hw_perf_counter_read(info);
+ struct perf_counter *counter = info;
+
+ counter->hw_ops->hw_perf_counter_read(counter);
}
static u64 perf_counter_read(struct perf_counter *counter)
@@ -816,8 +815,10 @@
int cpu,
struct perf_counter *group_leader)
{
- struct perf_counter *counter = kzalloc(sizeof(*counter), GFP_KERNEL);
+ struct hw_perf_counter_ops *hw_ops;
+ struct perf_counter *counter;
+ counter = kzalloc(sizeof(*counter), GFP_KERNEL);
if (!counter)
return NULL;
@@ -839,6 +840,14 @@
counter->hw_event = *hw_event;
counter->wakeup_pending = 0;
counter->group_leader = group_leader;
+ counter->hw_ops = NULL;
+
+ hw_ops = hw_perf_counter_init(counter);
+ if (!hw_ops) {
+ kfree(counter);
+ return NULL;
+ }
+ counter->hw_ops = hw_ops;
return counter;
}
@@ -908,10 +917,6 @@
if (!counter)
goto err_put_context;
- ret = hw_perf_counter_init(counter);
- if (ret)
- goto err_free_put_context;
-
perf_install_in_context(ctx, counter, cpu);
ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
@@ -927,8 +932,6 @@
mutex_lock(&counter->mutex);
perf_counter_remove_from_context(counter);
mutex_unlock(&counter->mutex);
-
-err_free_put_context:
kfree(counter);
err_put_context: