On Fri, 2012-08-17 at 15:42 +0200, Jiri Slaby wrote:
> Before calling __ratelimit in __WARN_RATELIMIT, check the condition
> first. When this check was not there, we got constant income of:
> tty_init_dev: 60 callbacks suppressed
> tty_init_dev: 59 callbacks suppressed
[]
> diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
[]
> @@ -49,8 +49,9 @@ extern int ___ratelimit(struct ratelimit_state *rs, const
> char *func);
> #define __WARN_RATELIMIT(condition, state, format...) \
> ({ \
> int rtn = 0; \
> - if (unlikely(__ratelimit(state))) \
> - rtn = WARN(condition, format); \
> + int __rtcond = !!condition; \
> + if (unlikely(__rtcond && __ratelimit(state))) \
> + rtn = WARN(__rtcond, format); \
> rtn; \
> })
>
Hi Jiri.
This seems fine to me but are there any conditions that
are computationally expensive? ratelimit(state) isn't
and this will now always do condition.
(looks instead of speculates)
There's 1 current use of WARN_RATELIMIT and there's
a condition of 1 so there's no problem here.
__WARN_RATELIMIT is pretty stupid.
It's only called from WARN_RATELIMIT.
I think it shouldn't exist at all.
Maybe something like this?
(has some neatening as well)
include/linux/ratelimit.h | 27 +++++++++------------------
1 files changed, 9 insertions(+), 18 deletions(-)
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
index e11ccb4..f4acd61 100644
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -46,20 +46,17 @@ extern int ___ratelimit(struct ratelimit_state *rs, const
char *func);
#define WARN_ON_RATELIMIT(condition, state) \
WARN_ON((condition) && __ratelimit(state))
-#define __WARN_RATELIMIT(condition, state, format...) \
-({ \
- int rtn = 0; \
- if (unlikely(__ratelimit(state))) \
- rtn = WARN(condition, format); \
- rtn; \
-})
-
-#define WARN_RATELIMIT(condition, format...) \
+#define WARN_RATELIMIT(condition, fmt, ...) \
({ \
static DEFINE_RATELIMIT_STATE(_rs, \
DEFAULT_RATELIMIT_INTERVAL, \
DEFAULT_RATELIMIT_BURST); \
- __WARN_RATELIMIT(condition, &_rs, format); \
+ int rtn = !!(condition); \
+ \
+ if (unlikely(rtn && __ratelimit(state))) \
+ WARN(rtn, fmt, ##__VA_ARGS__); \
+ \
+ rtn; \
})
#else
@@ -67,15 +64,9 @@ extern int ___ratelimit(struct ratelimit_state *rs, const
char *func);
#define WARN_ON_RATELIMIT(condition, state) \
WARN_ON(condition)
-#define __WARN_RATELIMIT(condition, state, format...) \
-({ \
- int rtn = WARN(condition, format); \
- rtn; \
-})
-
-#define WARN_RATELIMIT(condition, format...) \
+#define WARN_RATELIMIT(condition, fmt, ...) \
({ \
- int rtn = WARN(condition, format); \
+ int rtn = WARN(condition, fmt, ##__VA_ARGS__); \
rtn; \
})
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