ring-buffer: Add event descriptor to simplify passing data
Add rb_event_info descriptor to pass event info to functions a bit easier than using a bunch of parameters. This will also allow for changing the code around a bit to find better fast paths. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat)
Steven Rostedt
Родитель
5e2d5ef8ec
Коммит
fcc742eaad
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@ -399,6 +399,17 @@ struct rb_irq_work {
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bool wakeup_full;
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};
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/*
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* Structure to hold event state and handle nested events.
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*/
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struct rb_event_info {
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u64 ts;
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u64 delta;
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unsigned long length;
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struct buffer_page *tail_page;
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int add_timestamp;
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};
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/*
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* Used for which event context the event is in.
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* NMI = 0
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@ -2000,9 +2011,12 @@ rb_add_time_stamp(struct ring_buffer_event *event, u64 delta)
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*/
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static void
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rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
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struct ring_buffer_event *event, unsigned length,
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int add_timestamp, u64 delta)
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struct ring_buffer_event *event,
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struct rb_event_info *info)
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{
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unsigned length = info->length;
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u64 delta = info->delta;
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/* Only a commit updates the timestamp */
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if (unlikely(!rb_event_is_commit(cpu_buffer, event)))
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delta = 0;
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@ -2011,7 +2025,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
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* If we need to add a timestamp, then we
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* add it to the start of the resevered space.
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*/
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if (unlikely(add_timestamp)) {
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if (unlikely(info->add_timestamp)) {
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event = rb_add_time_stamp(event, delta);
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length -= RB_LEN_TIME_EXTEND;
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delta = 0;
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@ -2203,10 +2217,11 @@ static unsigned rb_calculate_event_length(unsigned length)
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static inline void
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rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
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struct buffer_page *tail_page,
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unsigned long tail, unsigned long length)
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unsigned long tail, struct rb_event_info *info)
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{
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struct buffer_page *tail_page = info->tail_page;
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struct ring_buffer_event *event;
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unsigned long length = info->length;
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/*
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* Only the event that crossed the page boundary
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@ -2276,13 +2291,14 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
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*/
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static noinline struct ring_buffer_event *
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rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
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unsigned long length, unsigned long tail,
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struct buffer_page *tail_page, u64 ts)
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unsigned long tail, struct rb_event_info *info)
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{
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struct buffer_page *tail_page = info->tail_page;
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struct buffer_page *commit_page = cpu_buffer->commit_page;
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struct ring_buffer *buffer = cpu_buffer->buffer;
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struct buffer_page *next_page;
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int ret;
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u64 ts;
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next_page = tail_page;
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@ -2368,25 +2384,24 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
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out_again:
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rb_reset_tail(cpu_buffer, tail_page, tail, length);
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rb_reset_tail(cpu_buffer, tail, info);
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/* fail and let the caller try again */
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return ERR_PTR(-EAGAIN);
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out_reset:
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/* reset write */
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rb_reset_tail(cpu_buffer, tail_page, tail, length);
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rb_reset_tail(cpu_buffer, tail, info);
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return NULL;
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}
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static struct ring_buffer_event *
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__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
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unsigned long length, u64 ts,
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u64 delta, int add_timestamp)
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struct rb_event_info *info)
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{
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struct buffer_page *tail_page;
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struct ring_buffer_event *event;
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struct buffer_page *tail_page;
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unsigned long tail, write;
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/*
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@ -2394,33 +2409,32 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
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* hold in the time field of the event, then we append a
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* TIME EXTEND event ahead of the data event.
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*/
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if (unlikely(add_timestamp))
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length += RB_LEN_TIME_EXTEND;
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if (unlikely(info->add_timestamp))
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info->length += RB_LEN_TIME_EXTEND;
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tail_page = cpu_buffer->tail_page;
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write = local_add_return(length, &tail_page->write);
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tail_page = info->tail_page = cpu_buffer->tail_page;
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write = local_add_return(info->length, &tail_page->write);
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/* set write to only the index of the write */
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write &= RB_WRITE_MASK;
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tail = write - length;
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tail = write - info->length;
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/*
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* If this is the first commit on the page, then it has the same
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* timestamp as the page itself.
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*/
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if (!tail)
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delta = 0;
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info->delta = 0;
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/* See if we shot pass the end of this buffer page */
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if (unlikely(write > BUF_PAGE_SIZE))
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return rb_move_tail(cpu_buffer, length, tail,
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tail_page, ts);
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return rb_move_tail(cpu_buffer, tail, info);
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/* We reserved something on the buffer */
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event = __rb_page_index(tail_page, tail);
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kmemcheck_annotate_bitfield(event, bitfield);
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rb_update_event(cpu_buffer, event, length, add_timestamp, delta);
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rb_update_event(cpu_buffer, event, info);
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local_inc(&tail_page->entries);
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@ -2429,10 +2443,10 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
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* its timestamp.
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*/
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if (!tail)
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tail_page->page->time_stamp = ts;
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tail_page->page->time_stamp = info->ts;
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/* account for these added bytes */
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local_add(length, &cpu_buffer->entries_bytes);
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local_add(info->length, &cpu_buffer->entries_bytes);
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return event;
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}
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@ -2521,9 +2535,8 @@ rb_reserve_next_event(struct ring_buffer *buffer,
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unsigned long length)
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{
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struct ring_buffer_event *event;
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u64 ts, delta;
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struct rb_event_info info;
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int nr_loops = 0;
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int add_timestamp;
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u64 diff;
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rb_start_commit(cpu_buffer);
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@ -2543,10 +2556,10 @@ rb_reserve_next_event(struct ring_buffer *buffer,
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}
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#endif
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length = rb_calculate_event_length(length);
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info.length = rb_calculate_event_length(length);
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again:
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add_timestamp = 0;
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delta = 0;
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info.add_timestamp = 0;
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info.delta = 0;
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/*
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* We allow for interrupts to reenter here and do a trace.
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@ -2560,35 +2573,35 @@ rb_reserve_next_event(struct ring_buffer *buffer,
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if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
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goto out_fail;
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ts = rb_time_stamp(cpu_buffer->buffer);
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diff = ts - cpu_buffer->write_stamp;
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info.ts = rb_time_stamp(cpu_buffer->buffer);
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diff = info.ts - cpu_buffer->write_stamp;
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/* make sure this diff is calculated here */
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barrier();
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/* Did the write stamp get updated already? */
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if (likely(ts >= cpu_buffer->write_stamp)) {
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delta = diff;
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if (unlikely(test_time_stamp(delta))) {
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if (likely(info.ts >= cpu_buffer->write_stamp)) {
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info.delta = diff;
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if (unlikely(test_time_stamp(info.delta))) {
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int local_clock_stable = 1;
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#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
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local_clock_stable = sched_clock_stable();
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#endif
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WARN_ONCE(delta > (1ULL << 59),
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WARN_ONCE(info.delta > (1ULL << 59),
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KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",
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(unsigned long long)delta,
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(unsigned long long)ts,
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(unsigned long long)info.delta,
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(unsigned long long)info.ts,
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(unsigned long long)cpu_buffer->write_stamp,
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local_clock_stable ? "" :
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"If you just came from a suspend/resume,\n"
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"please switch to the trace global clock:\n"
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" echo global > /sys/kernel/debug/tracing/trace_clock\n");
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add_timestamp = 1;
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info.add_timestamp = 1;
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}
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}
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event = __rb_reserve_next(cpu_buffer, length, ts,
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delta, add_timestamp);
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event = __rb_reserve_next(cpu_buffer, &info);
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if (unlikely(PTR_ERR(event) == -EAGAIN))
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goto again;
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