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| author | Rik van Riel <riel@redhat.com> | 2014-04-26 23:15:35 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-05-19 10:52:04 -0700 |
| commit | 61f38db3e3c0e4c3be0858750e2cabeadaecac0c (patch) | |
| tree | 5ded19f41e8ceb49a55b2942fb0a5774a95126d1 | |
| parent | e534165bbf6a04d001748c573c7d6a7bae3713a5 (diff) | |
| download | blackbird-op-linux-61f38db3e3c0e4c3be0858750e2cabeadaecac0c.tar.gz blackbird-op-linux-61f38db3e3c0e4c3be0858750e2cabeadaecac0c.zip | |
rcu: Provide API to suppress stall warnings while sysrc runs
Some sysrq handlers can run for a long time, because they dump a lot
of data onto a serial console. Having RCU stall warnings pop up in
the middle of them only makes the problem worse.
This commit provides rcu_sysrq_start() and rcu_sysrq_end() APIs to
temporarily suppress RCU CPU stall warnings while a sysrq request is
handled.
Signed-off-by: Rik van Riel <riel@redhat.com>
[ paulmck: Fix TINY_RCU build error. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | include/linux/rcupdate.h | 12 | ||||
| -rw-r--r-- | kernel/rcu/update.c | 12 |
2 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 9ccd644c1234..5a75d19aa661 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -248,6 +248,18 @@ void rcu_idle_exit(void); void rcu_irq_enter(void); void rcu_irq_exit(void); +#ifdef CONFIG_RCU_STALL_COMMON +void rcu_sysrq_start(void); +void rcu_sysrq_end(void); +#else /* #ifdef CONFIG_RCU_STALL_COMMON */ +static inline void rcu_sysrq_start(void) +{ +} +static inline void rcu_sysrq_end(void) +{ +} +#endif /* #else #ifdef CONFIG_RCU_STALL_COMMON */ + #ifdef CONFIG_RCU_USER_QS void rcu_user_enter(void); void rcu_user_exit(void); diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index ed7a0d72562c..a2aeb4df0f60 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -320,6 +320,18 @@ int rcu_jiffies_till_stall_check(void) return till_stall_check * HZ + RCU_STALL_DELAY_DELTA; } +void rcu_sysrq_start(void) +{ + if (!rcu_cpu_stall_suppress) + rcu_cpu_stall_suppress = 2; +} + +void rcu_sysrq_end(void) +{ + if (rcu_cpu_stall_suppress == 2) + rcu_cpu_stall_suppress = 0; +} + static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) { rcu_cpu_stall_suppress = 1; |
