Commit-ID: afbab76a62b69ea6197e19727d4b8a8aef8deb25
Gitweb: http://git.kernel.org/tip/afbab76a62b69ea6197e19727d4b8a8aef8deb25
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Fri, 1 May 2009 19:40:05 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Tue, 5 May 2009 16:58:24 -0400
ring-buffer: have read page swap increment counter with page entries
In the swap page ring buffer code that is used by the ftrace splice code,
we scan the page to increment the counter of entries read.
With the number of entries already in the page we simply need to add it.
[ Impact: speed up reading page from ring buffer ]
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 28 +++-------------------------
1 files changed, 3 insertions(+), 25 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 342eacc..9e42a74 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2785,28 +2785,6 @@ out:
}
EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
-static void rb_remove_entries(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_data_page *bpage,
- unsigned int offset)
-{
- struct ring_buffer_event *event;
- unsigned long head;
-
- __raw_spin_lock(&cpu_buffer->lock);
- for (head = offset; head < local_read(&bpage->commit);
- head += rb_event_length(event)) {
-
- event = __rb_data_page_index(bpage, head);
- if (RB_WARN_ON(cpu_buffer, rb_null_event(event)))
- return;
- /* Only count data entries */
- if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
- continue;
- cpu_buffer->read++;
- }
- __raw_spin_unlock(&cpu_buffer->lock);
-}
-
/**
* ring_buffer_alloc_read_page - allocate a page to read from buffer
* @buffer: the buffer to allocate for.
@@ -2977,6 +2955,9 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
/* we copied everything to the beginning */
read = 0;
} else {
+ /* update the entry counter */
+ cpu_buffer->read += local_read(&reader->entries);
+
/* swap the pages */
rb_init_page(bpage);
bpage = reader->page;
@@ -2985,9 +2966,6 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
local_set(&reader->entries, 0);
reader->read = 0;
*data_page = bpage;
-
- /* update the entry counter */
- rb_remove_entries(cpu_buffer, bpage, read);
}
ret = read;
--
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