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 000000000000..114f27f3a624
--- /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 */