Lines Matching refs:stall

3 The rcu_cpu_stall_suppress module parameter enables RCU's CPU stall
5 This module parameter enables CPU stall detection by default, but
7 The stall detector's idea of what constitutes "unduly delayed" is
14 	issues an RCU CPU stall warning.  This time period is normally
20 	So if you are 10 seconds into a 40-second stall, setting this
22 	-next- stall, or the following warning for the current stall
23 	(assuming the stall lasts long enough).  It will not affect the
24 	timing of the next warning for the current stall.
31 	This kernel configuration parameter causes the stall warning to
40 	giving an RCU CPU stall warning message.  (This is a cpp
45 	The CPU stall detector tries to make the offending CPU print its
47 	However, if the offending CPU does not detect its own stall in
55 	This boot/sysfs parameter controls the RCU-tasks stall warning
56 	interval.  A value of zero or less suppresses RCU-tasks stall
57 	warnings.  A positive value sets the stall-warning interval
58 	in jiffies.  An RCU-tasks stall warning starts wtih the line:
68 INFO: rcu_sched_state detected stall on CPU 5 (t=2500 jiffies)
70 This message indicates that CPU 5 detected that it was causing a stall,
71 and that the stall was affecting RCU-sched.  This message will normally be
77 On the other hand, if the offending CPU fails to print out a stall-warning
84 causing stalls, and that the stall was affecting RCU-bh.  This message
88 It is even possible for a rcu_preempt_state stall to be caused by both
92 Finally, if the grace period ends just as the stall warning starts
93 printing, there will be a spurious stall-warning message:
98 possible for a zero-jiffy stall to be flagged in this case, depending
99 on how the stall warning and the grace-period initialization happen to
105 more information is printed with the stall-warning message, for example:
107 	INFO: rcu_preempt detected stall on CPU
114 	INFO: rcu_preempt detected stall on CPU
140 across repeated stall-warning messages, it is possible that RCU's softirq
156 the stall warning, the following additional line is printed:
161 RCU CPU stall warnings even when all CPUs and tasks have passed through
167 If a stall lasts long enough, multiple stall-warning messages will be
171 of the stall and the first message.
176 So your kernel printed an RCU CPU stall warning.  The next question is
177 "What caused it?"  The following problems can result in RCU CPU stall
194 	does not necessarily prevent RCU CPU stall warnings.  Therefore,
211 	memory, you might see stall-warning messages.
219 	CONFIG_PREEMPT_RCU case, you might see stall-warning
225 	result in RCU CPU stall warnings for CONFIG_NO_HZ_COMMON=n kernels.
232 	This resulted in a series of RCU CPU stall warnings, eventually
235 The RCU, RCU-sched, RCU-bh, and RCU-tasks implementations have CPU stall
236 warning.  Note that SRCU does -not- have CPU stall warnings.  Please note
238 No grace period, no CPU stall warnings.
240 To diagnose the cause of the stall, inspect the stack traces.
242 If you have a series of stall warnings from a single extended stall,
243 comparing the stack traces can often help determine where the stall
246 If you can reliably trigger the stall, ftrace can be quite helpful.