[for-next][PATCH 11/14] tracing/histogram: Update division by 0 documentation

Steven Rostedt
2021-11-02T20:12:41Z

From: Kalesh Singh <kaleshsingh@google.com>

If the divisor is a constant and zero, the undeifned case can be
detected and an error returned instead of -1.

Link: https://lkml.kernel.org/r/20211029183339.3216491-3-kaleshsingh@google.com

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
Documentation/trace/histogram.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 66ec972dfb78..859fd1b76c63 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -1766,7 +1766,8 @@ using the same key and variable from yet another event::
Expressions support the use of addition, subtraction, multiplication and
division operators (+-\*/).

-Note that division by zero always returns -1.
+Note if division by zero cannot be detected at parse time (i.e. the
+divisor is not a constant), the result will be -1.

Numeric constants can also be used directly in an expression::

--
2.33.0