local_sub(length, &tail_page->write);
}
-static inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer);
-
/*
* This is the slow path, force gcc not to inline it.
*/
int ret;
u64 ts;
- /*
- * If the event had a timestamp attached to it, remove it.
- * The first event on a page (nested or not) always uses
- * the full timestamp of the new page.
- */
- if (info->add_timestamp) {
- info->add_timestamp = 0;
- info->length -= RB_LEN_TIME_EXTEND;
- }
-
next_page = tail_page;
rb_inc_page(cpu_buffer, &next_page);
rb_reset_tail(cpu_buffer, tail, info);
- /* Commit what we have for now to update timestamps */
- rb_end_commit(cpu_buffer);
- /* rb_end_commit() decs committing */
- local_inc(&cpu_buffer->committing);
-
/* fail and let the caller try again */
return ERR_PTR(-EAGAIN);
return skip_time_extend(event);
}
+static inline int rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
+ struct ring_buffer_event *event);
+
/**
* rb_update_event - update event type and data
* @event: the event to update
* and with this, we can determine what to place into the
* data field.
*/
-static void __always_inline
+static void
rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
struct ring_buffer_event *event,
struct rb_event_info *info)
unsigned length = info->length;
u64 delta = info->delta;
+ /* Only a commit updates the timestamp */
+ if (unlikely(!rb_event_is_commit(cpu_buffer, event)))
+ delta = 0;
+
/*
* If we need to add a timestamp, then we
* add it to the start of the resevered space.
static noinline void
rb_handle_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event,
struct rb_event_info *info)
{
- struct ring_buffer_event *padding;
- int length;
- int size;
-
WARN_ONCE(info->delta > (1ULL << 59),
KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",
(unsigned long long)info->delta,
"If you just came from a suspend/resume,\n"
"please switch to the trace global clock:\n"
" echo global > /sys/kernel/debug/tracing/trace_clock\n");
-
- /*
- * Discarding this event to add a timestamp in front, but
- * we still need to update the length of it to perform the discard.
- */
- rb_update_event(cpu_buffer, event, info);
-
- if (rb_try_to_discard(cpu_buffer, event)) {
- info->add_timestamp = 1;
- /*
- * The time delta since the last event is too big to
- * hold in the time field of the event, then we append a
- * TIME EXTEND event ahead of the data event.
- */
- info->length += RB_LEN_TIME_EXTEND;
- return;
- }
-
- /*
- * Humpf! An event came in after this one, and because it is not a
- * commit, it will have a delta of zero, thus, it will take on
- * the timestamp of the previous commit, which happened a long time
- * ago (we need to add a timestamp, remember?).
- * We need to add the timestamp here. A timestamp is a fixed size
- * of 8 bytes. That means the rest of the event needs to be
- * padding.
- */
- size = info->length - RB_LEN_TIME_EXTEND;
-
- /* The padding will have a delta of 1 */
- if (size)
- info->delta--;
-
- padding = rb_add_time_stamp(event, info->delta);
-
- if (size) {
- length = info->length;
- info->delta = 0;
- info->length = size;
- rb_update_event(cpu_buffer, padding, info);
-
- rb_event_discard(padding);
-
- /* Still visible, need to update write_stamp */
- rb_update_write_stamp(cpu_buffer, event);
-
- /* Still need to commit the padding. */
- rb_end_commit(cpu_buffer);
-
- /* rb_end_commit() decs committing */
- local_inc(&cpu_buffer->committing);
-
- /* The next iteration still uses the original length */
- info->length = length;
- }
+ info->add_timestamp = 1;
}
static struct ring_buffer_event *
struct ring_buffer_event *event;
struct buffer_page *tail_page;
unsigned long tail, write;
- bool is_commit;
+
+ /*
+ * If the time delta since the last event is too big to
+ * hold in the time field of the event, then we append a
+ * TIME EXTEND event ahead of the data event.
+ */
+ if (unlikely(info->add_timestamp))
+ info->length += RB_LEN_TIME_EXTEND;
tail_page = info->tail_page = cpu_buffer->tail_page;
write = local_add_return(info->length, &tail_page->write);
write &= RB_WRITE_MASK;
tail = write - info->length;
- /* See if we shot pass the end of this buffer page */
- if (unlikely(write > BUF_PAGE_SIZE))
- return rb_move_tail(cpu_buffer, tail, info);
-
- /* We reserved something on the buffer */
- event = __rb_page_index(tail_page, tail);
-
/*
* If this is the first commit on the page, then it has the same
- * timestamp as the page itself, otherwise we need to figure out
- * the delta.
+ * timestamp as the page itself.
*/
- info->ts = rb_time_stamp(cpu_buffer->buffer);
- is_commit = rb_event_is_commit(cpu_buffer, event);
-
- /* Commits are special (non nested events) */
- info->delta = is_commit ? info->ts - cpu_buffer->write_stamp : 0;
-
- if (!tail) {
- /*
- * If this is the first commit on the page, set the
- * page to its timestamp.
- */
- tail_page->page->time_stamp = info->ts;
+ if (!tail)
info->delta = 0;
- } else if (unlikely(test_time_stamp(info->delta)) &&
- !info->add_timestamp) {
- rb_handle_timestamp(cpu_buffer, event, info);
- return ERR_PTR(-EAGAIN);
- }
+ /* See if we shot pass the end of this buffer page */
+ if (unlikely(write > BUF_PAGE_SIZE))
+ return rb_move_tail(cpu_buffer, tail, info);
+ /* We reserved something on the buffer */
+
+ event = __rb_page_index(tail_page, tail);
kmemcheck_annotate_bitfield(event, bitfield);
rb_update_event(cpu_buffer, event, info);
local_inc(&tail_page->entries);
+ /*
+ * If this is the first commit on the page, then update
+ * its timestamp.
+ */
+ if (!tail)
+ tail_page->page->time_stamp = info->ts;
+
/* account for these added bytes */
local_add(info->length, &cpu_buffer->entries_bytes);
struct ring_buffer_event *event;
struct rb_event_info info;
int nr_loops = 0;
+ u64 diff;
rb_start_commit(cpu_buffer);
return NULL;
}
#endif
+
info.length = rb_calculate_event_length(length);
- info.add_timestamp = 0;
again:
+ info.add_timestamp = 0;
+ info.delta = 0;
+
/*
* We allow for interrupts to reenter here and do a trace.
* If one does, it will cause this original code to loop
if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
goto out_fail;
+ info.ts = rb_time_stamp(cpu_buffer->buffer);
+ diff = info.ts - cpu_buffer->write_stamp;
+
+ /* make sure this diff is calculated here */
+ barrier();
+
+ /* Did the write stamp get updated already? */
+ if (likely(info.ts >= cpu_buffer->write_stamp)) {
+ info.delta = diff;
+ if (unlikely(test_time_stamp(info.delta)))
+ rb_handle_timestamp(cpu_buffer, &info);
+ }
+
event = __rb_reserve_next(cpu_buffer, &info);
if (unlikely(PTR_ERR(event) == -EAGAIN))
git.samba.org / sfrench / cifs-2.6.git / commitdiff