perf: Split up buffer handling from core code

And create the internal perf events header.

v2: Keep an internal inlined perf_output_copy()

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1305827704-5607-1-git-send-email-fweisbec@gmail.com
[ v3: use clearer 'ring_buffer' and 'rb' naming ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 97 insertions, 0 deletions

diff --git a/kernel/events/internal.h b/kernel/events/internal.h
new file mode 100644
index 00000000000..114f27f3a62
--- /dev/null
+++ b/kernel/events/internal.h
@@ -0,0 +1,97 @@
+#ifndef _KERNEL_EVENTS_INTERNAL_H
+#define _KERNEL_EVENTS_INTERNAL_H
+
+#define RING_BUFFER_WRITABLE		0x01
+
+struct ring_buffer {
+	atomic_t			refcount;
+	struct rcu_head			rcu_head;
+#ifdef CONFIG_PERF_USE_VMALLOC
+	struct work_struct		work;
+	int				page_order;	/* allocation order  */
+#endif
+	int				nr_pages;	/* nr of data pages  */
+	int				writable;	/* are we writable   */
+
+	atomic_t			poll;		/* POLL_ for wakeups */
+
+	local_t				head;		/* write position    */
+	local_t				nest;		/* nested writers    */
+	local_t				events;		/* event limit       */
+	local_t				wakeup;		/* wakeup stamp      */
+	local_t				lost;		/* nr records lost   */
+
+	long				watermark;	/* wakeup watermark  */
+
+	struct perf_event_mmap_page	*user_page;
+	void				*data_pages[0];
+};
+
+
+extern void rb_free(struct ring_buffer *rb);
+extern struct ring_buffer *
+rb_alloc(int nr_pages, long watermark, int cpu, int flags);
+extern void perf_event_wakeup(struct perf_event *event);
+
+extern void
+perf_event_header__init_id(struct perf_event_header *header,
+			   struct perf_sample_data *data,
+			   struct perf_event *event);
+extern void
+perf_event__output_id_sample(struct perf_event *event,
+			     struct perf_output_handle *handle,
+			     struct perf_sample_data *sample);
+
+extern struct page *
+perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff);
+
+#ifdef CONFIG_PERF_USE_VMALLOC
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int page_order(struct ring_buffer *rb)
+{
+	return rb->page_order;
+}
+
+#else
+
+static inline int page_order(struct ring_buffer *rb)
+{
+	return 0;
+}
+#endif
+
+static unsigned long perf_data_size(struct ring_buffer *rb)
+{
+	return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
+}
+
+static inline void
+__output_copy(struct perf_output_handle *handle,
+		   const void *buf, unsigned int len)
+{
+	do {
+		unsigned long size = min_t(unsigned long, handle->size, len);
+
+		memcpy(handle->addr, buf, size);
+
+		len -= size;
+		handle->addr += size;
+		buf += size;
+		handle->size -= size;
+		if (!handle->size) {
+			struct ring_buffer *rb = handle->rb;
+
+			handle->page++;
+			handle->page &= rb->nr_pages - 1;
+			handle->addr = rb->data_pages[handle->page];
+			handle->size = PAGE_SIZE << page_order(rb);
+		}
+	} while (len);
+}
+
+#endif /* _KERNEL_EVENTS_INTERNAL_H */