From 61f38db3e3c0e4c3be0858750e2cabeadaecac0c Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Sat, 26 Apr 2014 23:15:35 -0700 Subject: 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 [ paulmck: Fix TINY_RCU build error. ] Signed-off-by: Paul E. McKenney --- kernel/rcu/update.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'kernel/rcu') diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index ed7a0d7..a2aeb4d 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; -- cgit v1.1