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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2021-03-16 12:41:02 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-03-18 12:58:25 -0400
commit8672e4948d0c44272cc05f8ff563dbf6b6c1289f (patch)
tree51a37becdd3c3a8f55c473520226183e6ec05c30
parente20044f7e9ae2b5395ca3ae9bd0907fdf43357a7 (diff)
ring-buffer: Add a event_stamp to cpu_buffer for each level of nesting
Add a place to save the current event time stamp for each level of nesting. This will be used to retrieve the time stamp of the current event before it is committed. Link: https://lkml.kernel.org/r/20210316164113.399089673@goodmis.org Reviewed-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-rw-r--r--kernel/trace/ring_buffer.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 941ac2021b97..470d97169081 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -492,6 +492,8 @@ struct rb_time_struct {
#endif
typedef struct rb_time_struct rb_time_t;
+#define MAX_NEST 5
+
/*
* head_page == tail_page && head == tail then buffer is empty.
*/
@@ -529,6 +531,7 @@ struct ring_buffer_per_cpu {
unsigned long read_bytes;
rb_time_t write_stamp;
rb_time_t before_stamp;
+ u64 event_stamp[MAX_NEST];
u64 read_stamp;
/* ring buffer pages to update, > 0 to add, < 0 to remove */
long nr_pages_to_update;
@@ -2715,6 +2718,10 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
{
unsigned length = info->length;
u64 delta = info->delta;
+ unsigned int nest = local_read(&cpu_buffer->committing) - 1;
+
+ if (nest < MAX_NEST)
+ cpu_buffer->event_stamp[nest] = info->ts;
/*
* If we need to add a timestamp, then we
@@ -3456,7 +3463,6 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
info->after, ts)) {
/* Nothing came after this event between C and E */
info->delta = ts - info->after;
- info->ts = ts;
} else {
/*
* Interrupted between C and E:
@@ -3468,6 +3474,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
*/
info->delta = 0;
}
+ info->ts = ts;
info->add_timestamp &= ~RB_ADD_STAMP_FORCE;
}
@@ -5026,6 +5033,8 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
rb_time_set(&cpu_buffer->write_stamp, 0);
rb_time_set(&cpu_buffer->before_stamp, 0);
+ memset(cpu_buffer->event_stamp, 0, sizeof(cpu_buffer->event_stamp));
+
cpu_buffer->lost_events = 0;
cpu_buffer->last_overrun = 0;

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