From 979f693def9084a452846365dfde5dcb28366333 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Tue, 22 Sep 2009 14:44:11 +0200
Subject: ratelimit: Use per ratelimit context locking
I'd like to use printk_ratelimit() in atomic context, but that's
not possible right now due to the spinlock usage this commit
introduced more than a year ago:
717115e: printk ratelimiting rewrite
As a first step push the lock into the ratelimit state structure.
This allows us to deal with locking failures to be considered as an
event related to that state being too busy.
Also clean up the code a bit (without changing functionality):
- tidy up the definitions
- clean up the code flow
This also shrinks the code a tiny bit:
text data bss dec hex filename
264 0 4 268 10c ratelimit.o.before
255 0 0 255 ff ratelimit.o.after
( Whole-kernel data size got a bit larger, because we have
two ratelimit-state data structures right now. )
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David S. Miller <davem@davemloft.net>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/ratelimit.h | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
(limited to 'include/linux/ratelimit.h')
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
index 00044b85645..187bc16c1f1 100644
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -1,20 +1,30 @@
#ifndef _LINUX_RATELIMIT_H
#define _LINUX_RATELIMIT_H
+
#include <linux/param.h>
+#include <linux/spinlock_types.h>
-#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
-#define DEFAULT_RATELIMIT_BURST 10
+#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
+#define DEFAULT_RATELIMIT_BURST 10
struct ratelimit_state {
- int interval;
- int burst;
- int printed;
- int missed;
- unsigned long begin;
+ spinlock_t lock; /* protect the state */
+
+ int interval;
+ int burst;
+ int printed;
+ int missed;
+ unsigned long begin;
};
-#define DEFINE_RATELIMIT_STATE(name, interval, burst) \
- struct ratelimit_state name = {interval, burst,}
+#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
+ \
+ struct ratelimit_state name = { \
+ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
+ .interval = interval_init, \
+ .burst = burst_init, \
+ }
extern int __ratelimit(struct ratelimit_state *rs);
-#endif
+
+#endif /* _LINUX_RATELIMIT_H */
--
cgit v1.2.3-70-g09d2
From 5c828713358cb9df8aa174371edcbbb62203a490 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Fri, 23 Oct 2009 14:58:11 +0200
Subject: ratelimit: Make suppressed output messages more useful
Today I got:
[39648.224782] Registered led device: iwl-phy0::TX
[40676.545099] __ratelimit: 246 callbacks suppressed
[40676.545103] abcdef[23675]: segfault at 0 ...
as you can see the ratelimit message contains a function prefix.
Since this is always __ratelimit, this wont help much.
This patch changes __ratelimit and printk_ratelimit to print the
function name that calls ratelimit.
This will pinpoint the responsible function, as long as not several
different places call ratelimit with the same ratelimit state at
the same time. In that case we catch only one random function that
calls ratelimit after the wait period.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/kernel.h | 3 ++-
include/linux/ratelimit.h | 3 ++-
kernel/printk.c | 6 +++---
lib/ratelimit.c | 6 +++---
4 files changed, 10 insertions(+), 8 deletions(-)
(limited to 'include/linux/ratelimit.h')
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 3305f33201b..21d0d822c71 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -240,7 +240,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
asmlinkage int printk(const char * fmt, ...)
__attribute__ ((format (printf, 1, 2))) __cold;
-extern int printk_ratelimit(void);
+extern int __printk_ratelimit(const char *func);
+#define printk_ratelimit() __printk_ratelimit(__func__)
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
unsigned int interval_msec);
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
index 187bc16c1f1..668cf1bef03 100644
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -25,6 +25,7 @@ struct ratelimit_state {
.burst = burst_init, \
}
-extern int __ratelimit(struct ratelimit_state *rs);
+extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
+#define __ratelimit(state) ___ratelimit(state, __func__)
#endif /* _LINUX_RATELIMIT_H */
diff --git a/kernel/printk.c b/kernel/printk.c
index b997c893cdc..8283dbe15af 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1364,11 +1364,11 @@ late_initcall(disable_boot_consoles);
*/
DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
-int printk_ratelimit(void)
+int __printk_ratelimit(const char *func)
{
- return __ratelimit(&printk_ratelimit_state);
+ return ___ratelimit(&printk_ratelimit_state, func);
}
-EXPORT_SYMBOL(printk_ratelimit);
+EXPORT_SYMBOL(__printk_ratelimit);
/**
* printk_timed_ratelimit - caller-controlled printk ratelimiting
diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index 5551731ae1d..09f5ce1810d 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -20,7 +20,7 @@
* This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
* in every @rs->ratelimit_jiffies
*/
-int __ratelimit(struct ratelimit_state *rs)
+int ___ratelimit(struct ratelimit_state *rs, const char *func)
{
unsigned long flags;
int ret;
@@ -43,7 +43,7 @@ int __ratelimit(struct ratelimit_state *rs)
if (time_is_before_jiffies(rs->begin + rs->interval)) {
if (rs->missed)
printk(KERN_WARNING "%s: %d callbacks suppressed\n",
- __func__, rs->missed);
+ func, rs->missed);
rs->begin = 0;
rs->printed = 0;
rs->missed = 0;
@@ -59,4 +59,4 @@ int __ratelimit(struct ratelimit_state *rs)
return ret;
}
-EXPORT_SYMBOL(__ratelimit);
+EXPORT_SYMBOL(___ratelimit);
--
cgit v1.2.3-70-g09d2