ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index

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>
This commit is contained in:
Steven Rostedt 2009-06-11 09:29:58 -04:00 committed by Steven Rostedt
parent 44ad18e0a6
commit 22f470f8da

View File

@ -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