From 6634ff26cce2da04e5c2a5481bcb8888e7d01786 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 6 May 2009 15:30:07 -0400 Subject: ring-buffer: make moving the tail page a separate function Ingo Molnar thought the code would be cleaner if we used a function call instead of a goto for moving the tail page. After implementing this, it seems that gcc still inlines the result and the output is pretty much the same. Since this is considered a cleaner approach, might as well implement it. [ Impact: code clean up ] Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 89 +++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 40 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 03ed52b67db..3ae5ccf2c0f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1154,51 +1154,18 @@ static unsigned rb_calculate_event_length(unsigned length) return length; } + static struct ring_buffer_event * -__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, - unsigned type, unsigned long length, u64 *ts) +rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer, + unsigned long length, unsigned long tail, + struct buffer_page *commit_page, + struct buffer_page *tail_page, u64 *ts) { - struct buffer_page *tail_page, *head_page, *reader_page, *commit_page; - struct buffer_page *next_page; - unsigned long tail, write; + struct buffer_page *next_page, *head_page, *reader_page; struct ring_buffer *buffer = cpu_buffer->buffer; struct ring_buffer_event *event; - unsigned long flags; bool lock_taken = false; - - commit_page = cpu_buffer->commit_page; - /* we just need to protect against interrupts */ - barrier(); - tail_page = cpu_buffer->tail_page; - write = local_add_return(length, &tail_page->write); - tail = write - length; - - /* See if we shot pass the end of this buffer page */ - if (write > BUF_PAGE_SIZE) - goto next_page; - - /* We reserved something on the buffer */ - - if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE)) - return NULL; - - event = __rb_page_index(tail_page, tail); - rb_update_event(event, type, length); - - /* The passed in type is zero for DATA */ - if (likely(!type)) - local_inc(&tail_page->entries); - - /* - * If this is a commit and the tail is zero, then update - * this page's time stamp. - */ - if (!tail && rb_is_commit(cpu_buffer, event)) - cpu_buffer->commit_page->page->time_stamp = *ts; - - return event; - - next_page: + unsigned long flags; next_page = tail_page; @@ -1318,6 +1285,48 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, return NULL; } +static struct ring_buffer_event * +__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, + unsigned type, unsigned long length, u64 *ts) +{ + struct buffer_page *tail_page, *commit_page; + struct ring_buffer_event *event; + unsigned long tail, write; + + commit_page = cpu_buffer->commit_page; + /* we just need to protect against interrupts */ + barrier(); + tail_page = cpu_buffer->tail_page; + write = local_add_return(length, &tail_page->write); + tail = write - length; + + /* See if we shot pass the end of this buffer page */ + if (write > BUF_PAGE_SIZE) + return rb_move_tail(cpu_buffer, length, tail, + commit_page, tail_page, ts); + + /* We reserved something on the buffer */ + + if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE)) + return NULL; + + event = __rb_page_index(tail_page, tail); + rb_update_event(event, type, length); + + /* The passed in type is zero for DATA */ + if (likely(!type)) + local_inc(&tail_page->entries); + + /* + * If this is a commit and the tail is zero, then update + * this page's time stamp. + */ + if (!tail && rb_is_commit(cpu_buffer, event)) + cpu_buffer->commit_page->page->time_stamp = *ts; + + return event; +} + static int rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts, u64 *delta) -- cgit v1.2.3