Messages in this thread Patch in this message | | | Date | Wed, 17 Jun 2009 19:25:56 -0400 | From | Steven Rostedt <> | Subject | [PATCH 1/7] ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index |
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From: Steven Rostedt <srostedt@redhat.com>
The index of the event is found by masking PAGE_MASK to it and subtracting the header size. Currently the header size is calculate by PAGE_SIZE - BUF_PAGE_SIZE, when we already have a macro BUF_PAGE_HDR_SIZE to define it.
If we want to change BUF_PAGE_SIZE to something less than filling the rest of the page (this is done for debugging), then we break the algorithm to find the index.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/ring_buffer.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index ed35599..6b17a11 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1013,7 +1013,7 @@ rb_event_index(struct ring_buffer_event *event) { unsigned long addr = (unsigned long)event; - return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE); + return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE; } static inline int -- 1.6.3.1 --
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