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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-02-27 04:47:00 -0500
committerIngo Molnar <mingo@elte.hu>2012-03-12 15:43:16 -0400
commit3ccf3e8306156a28213adc720aba807e9a901ad5 (patch)
tree5b9db344b702299ea7eb53fbff3d0d74707d40ec /include/linux/printk.h
parent554cecaf733623b327eef9652b65965eb1081b81 (diff)
printk/sched: Introduce special printk_sched() for those awkward moments
There's a few awkward printk()s inside of scheduler guts that people prefer to keep but really are rather deadlock prone. Fudge around it by storing the text in a per-cpu buffer and poll it using the existing printk_tick() handler. This will drop output when its more frequent than once a tick, however only the affinity thing could possible go that fast and for that just one should suffice to notify the admin he's done something silly.. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-wua3lmkt3dg8nfts66o6brne@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/printk.h')
-rw-r--r--include/linux/printk.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h
index f0e22f75143f..1f77a4174ee0 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -101,6 +101,11 @@ asmlinkage __printf(1, 2) __cold
101int printk(const char *fmt, ...); 101int printk(const char *fmt, ...);
102 102
103/* 103/*
104 * Special printk facility for scheduler use only, _DO_NOT_USE_ !
105 */
106__printf(1, 2) __cold int printk_sched(const char *fmt, ...);
107
108/*
104 * Please don't use printk_ratelimit(), because it shares ratelimiting state 109 * Please don't use printk_ratelimit(), because it shares ratelimiting state
105 * with all other unrelated printk_ratelimit() callsites. Instead use 110 * with all other unrelated printk_ratelimit() callsites. Instead use
106 * printk_ratelimited() or plain old __ratelimit(). 111 * printk_ratelimited() or plain old __ratelimit().
@@ -127,6 +132,11 @@ int printk(const char *s, ...)
127{ 132{
128 return 0; 133 return 0;
129} 134}
135static inline __printf(1, 2) __cold
136int printk_sched(const char *s, ...)
137{
138 return 0;
139}
130static inline int printk_ratelimit(void) 140static inline int printk_ratelimit(void)
131{ 141{
132 return 0; 142 return 0;