From 033601a32b2012b6948e80e739cca40bff4de4a0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 21 Nov 2008 12:41:55 -0500 Subject: ring-buffer: add tracing_off_permanent Impact: feature to permanently disable ring buffer This patch adds a API to the ring buffer code that will permanently disable the ring buffer from ever recording. This should only be called when some serious anomaly is detected, and the system may be in an unstable state. When that happens, shutting down the recording to the ring buffers may be appropriate. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- include/linux/ring_buffer.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/ring_buffer.h') diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index e097c2e6b6dc..3bb87a753fa3 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -122,6 +122,7 @@ void ring_buffer_normalize_time_stamp(int cpu, u64 *ts); void tracing_on(void); void tracing_off(void); +void tracing_off_permanent(void); enum ring_buffer_flags { RB_FL_OVERWRITE = 1 << 0, -- cgit v1.2.1 From 8789a9e7df6bf9b93739c4c7d4e380725bc9e936 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 2 Dec 2008 15:34:07 -0500 Subject: ring-buffer: read page interface Impact: new API to ring buffer This patch adds a new interface into the ring buffer that allows a page to be read from the ring buffer on a given CPU. For every page read, one must also be given to allow for a "swap" of the pages. rpage = ring_buffer_alloc_read_page(buffer); if (!rpage) goto err; ret = ring_buffer_read_page(buffer, &rpage, cpu, full); if (!ret) goto empty; process_page(rpage); ring_buffer_free_read_page(rpage); The caller of these functions must handle any waits that are needed to wait for new data. The ring_buffer_read_page will simply return 0 if there is no data, or if "full" is set and the writer is still on the current page. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- include/linux/ring_buffer.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/ring_buffer.h') diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index 3bb87a753fa3..1a350a847edd 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -124,6 +124,11 @@ void tracing_on(void); void tracing_off(void); void tracing_off_permanent(void); +void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); +void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); +int ring_buffer_read_page(struct ring_buffer *buffer, + void **data_page, int cpu, int full); + enum ring_buffer_flags { RB_FL_OVERWRITE = 1 << 0, }; -- cgit v1.2.1 From 361b73d5c34f59c3fd107bb9dbe7a1fbff2c2517 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Mon, 8 Dec 2008 10:58:08 +0800 Subject: ring_buffer: fix comments Impact: comments cleanup fix incorrect comments for enum ring_buffer_type Signed-off-by: Lai Jiangshan Signed-off-by: Ingo Molnar --- include/linux/ring_buffer.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'include/linux/ring_buffer.h') diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index 1a350a847edd..d363467c8f13 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -28,17 +28,19 @@ struct ring_buffer_event { * size = 8 bytes * * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock - * array[0] = tv_nsec - * array[1] = tv_sec + * array[0] = tv_nsec + * array[1..2] = tv_sec * size = 16 bytes * * @RINGBUF_TYPE_DATA: Data record * If len is zero: * array[0] holds the actual length - * array[1..(length+3)/4-1] holds data + * array[1..(length+3)/4] holds data + * size = 4 + 4 + length (bytes) * else * length = len << 2 - * array[0..(length+3)/4] holds data + * array[0..(length+3)/4-1] holds data + * size = 4 + length (bytes) */ enum ring_buffer_type { RINGBUF_TYPE_PADDING, -- cgit v1.2.1