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authorSteven Rostedt <srostedt@redhat.com>2009-04-29 21:43:37 +0400
committerSteven Rostedt <rostedt@goodmis.org>2009-05-05 21:51:02 +0400
commitf0d2c681ac0a85142fc8abe65fc33fcad35cb9b7 (patch)
treeeafd2b655fc7ad0695fc5dbc343bcc1eb17e2e32 /include/linux/ring_buffer.h
parentd6ce96dabe2c4409fd009ec14250a1fdbab4b133 (diff)
downloadlinux-f0d2c681ac0a85142fc8abe65fc33fcad35cb9b7.tar.xz
ring-buffer: add counters for commit overrun and nmi dropped entries
The WARN_ON in the ring buffer when a commit is preempted and the buffer is filled by preceding writes can happen in normal operations. The WARN_ON makes it look like a bug, not to mention, because it does not stop tracing and calls printk which can also recurse, this is prone to deadlock (the WARN_ON is not in a position to recurse). This patch removes the WARN_ON and replaces it with a counter that can be retrieved by a tracer. This counter is called commit_overrun. While at it, I added a nmi_dropped counter to count any time an NMI entry is dropped because the NMI could not take the spinlock. [ Impact: prevent deadlock by printing normal case warning ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ring_buffer.h')
-rw-r--r--include/linux/ring_buffer.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 1c2f80911fbe..f1345828c7c5 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -153,6 +153,8 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer);
unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,