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SubjectRe: [PATCH 1/3] ring-buffer: add counters for commit overrun and nmi dropped entries

On Thu, 30 Apr 2009, Andrew Morton wrote:

> On Thu, 30 Apr 2009 23:33:31 -0400 (EDT) Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > > Should you decide to retire the paste pot, and if you can bear to move
> > > `struct ring_buffer' into a header, these four functions could be made
> > > static inlines, with pleasant runtime results.
> >
> > Well, the only users of these functions are those that output to user
> > land. The latency format and the stat file.
>
> OK, that's slowpath. They were exported to modules - are these files a
> per-tracer thing?

A ring buffer can be allocated per tracer (although ftrace does not -yet-
do this). Some of these are for per_cpu parts of the ring buffer. The ring
buffer has a buffer per cpu.

As for the EXPORT_SYMBOLs. See this commit (and I added Robert to the Cc)

commit c4f50183f90fb1fd99aa5941f01b90cd1b882d2e
Author: Robert Richter <robert.richter@amd.com>
Date: Thu Dec 11 16:49:22 2008 +0100

ring_buffer: adding EXPORT_SYMBOLs

I added EXPORT_SYMBOL_GPLs for all functions part of the API
(ring_buffer.h). This is required since oprofile is using the ring
buffer and the compilation as modules would fail otherwise.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


So it looks like it was just a "give modules all access to the ring
buffer" commit.

-- Steve



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