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authorRik van Riel <riel@redhat.com>2014-04-26 23:15:35 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-05-19 10:52:04 -0700
commit61f38db3e3c0e4c3be0858750e2cabeadaecac0c (patch)
tree5ded19f41e8ceb49a55b2942fb0a5774a95126d1 /kernel/rcu/update.c
parente534165bbf6a04d001748c573c7d6a7bae3713a5 (diff)
downloadlinux-sh-61f38db3e3c0e4c3be0858750e2cabeadaecac0c.tar.gz
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>
Diffstat (limited to 'kernel/rcu/update.c')
-rw-r--r--kernel/rcu/update.c12
1 files changed, 12 insertions, 0 deletions
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;