perf_counter: small cleanup of the output routines

Move the nmi argument to the _begin() function, so that _end() only needs the
handle. This allows the _begin() function to generate a wakeup on event loss.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171023.959404268@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d07b452..4471e7e 100644 (file)
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1663,10 +1663,20 @@ struct perf_output_handle {
        unsigned int            offset;
        unsigned int            head;
        int                     wakeup;
+       int                     nmi;
 };
 
+static inline void __perf_output_wakeup(struct perf_output_handle *handle)
+{
+       if (handle->nmi)
+               perf_pending_queue(handle->counter);
+       else
+               perf_counter_wakeup(handle->counter);
+}
+
 static int perf_output_begin(struct perf_output_handle *handle,
-                            struct perf_counter *counter, unsigned int size)
+                            struct perf_counter *counter, unsigned int size,
+                            int nmi)
 {
        struct perf_mmap_data *data;
        unsigned int offset, head;
@@ -1676,15 +1686,17 @@ static int perf_output_begin(struct perf_output_handle *handle,
        if (!data)
                goto out;
 
+       handle->counter = counter;
+       handle->nmi     = nmi;
+
        if (!data->nr_pages)
-               goto out;
+               goto fail;
 
        do {
                offset = head = atomic_read(&data->head);
                head += size;
        } while (atomic_cmpxchg(&data->head, offset, head) != offset);
 
-       handle->counter = counter;
        handle->data    = data;
        handle->offset  = offset;
        handle->head    = head;
@@ -1692,6 +1704,8 @@ static int perf_output_begin(struct perf_output_handle *handle,
 
        return 0;
 
+fail:
+       __perf_output_wakeup(handle);
 out:
        rcu_read_unlock();
 
@@ -1733,14 +1747,10 @@ static void perf_output_copy(struct perf_output_handle *handle,
 #define perf_output_put(handle, x) \
        perf_output_copy((handle), &(x), sizeof(x))
 
-static void perf_output_end(struct perf_output_handle *handle, int nmi)
+static void perf_output_end(struct perf_output_handle *handle)
 {
-       if (handle->wakeup) {
-               if (nmi)
-                       perf_pending_queue(handle->counter);
-               else
-                       perf_counter_wakeup(handle->counter);
-       }
+       if (handle->wakeup)
+               __perf_output_wakeup(handle);
        rcu_read_unlock();
 }
 
@@ -1750,12 +1760,12 @@ static int perf_output_write(struct perf_counter *counter, int nmi,
        struct perf_output_handle handle;
        int ret;
 
-       ret = perf_output_begin(&handle, counter, size);
+       ret = perf_output_begin(&handle, counter, size, nmi);
        if (ret)
                goto out;
 
        perf_output_copy(&handle, buf, size);
-       perf_output_end(&handle, nmi);
+       perf_output_end(&handle);
 
 out:
        return ret;
@@ -1804,7 +1814,7 @@ static void perf_output_group(struct perf_counter *counter, int nmi)
 
        size = sizeof(header) + counter->nr_siblings * sizeof(entry);
 
-       ret = perf_output_begin(&handle, counter, size);
+       ret = perf_output_begin(&handle, counter, size, nmi);
        if (ret)
                return;
 
@@ -1824,7 +1834,7 @@ static void perf_output_group(struct perf_counter *counter, int nmi)
                perf_output_put(&handle, entry);
        }
 
-       perf_output_end(&handle, nmi);
+       perf_output_end(&handle);
 }
 
 void perf_counter_output(struct perf_counter *counter,
@@ -1869,7 +1879,7 @@ static void perf_counter_mmap_output(struct perf_counter *counter,
 {
        struct perf_output_handle handle;
        int size = mmap_event->event.header.size;
-       int ret = perf_output_begin(&handle, counter, size);
+       int ret = perf_output_begin(&handle, counter, size, 0);
 
        if (ret)
                return;
@@ -1877,7 +1887,7 @@ static void perf_counter_mmap_output(struct perf_counter *counter,
        perf_output_put(&handle, mmap_event->event);
        perf_output_copy(&handle, mmap_event->file_name,
                                   mmap_event->file_size);
-       perf_output_end(&handle, 0);
+       perf_output_end(&handle);
 }
 
 static int perf_counter_mmap_match(struct perf_counter *counter,