Merge remote-tracking branch 'md/for-next'

[karo-tx-linux.git] / Documentation / RCU / stallwarn.txt

diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index efb9454875ab7453255532887225ad0cb2d5d2fd..0f7fb4298e7e0b657a7df678ee0852de7ab7887d 100644 (file)
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -205,6 +205,13 @@ o  For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the
        behavior, you might need to replace some of the cond_resched()
        calls with calls to cond_resched_rcu_qs().
 
+o      Booting Linux using a console connection that is too slow to
+       keep up with the boot-time console-message rate.  For example,
+       a 115Kbaud serial console can be -way- too slow to keep up
+       with boot-time message rates, and will frequently result in
+       RCU CPU stall warning messages.  Especially if you have added
+       debug printk()s.
+
 o      Anything that prevents RCU's grace-period kthreads from running.
        This can result in the "All QSes seen" console-log message.
        This message will include information on when the kthread last