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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-06-30 14:54:09 -0700 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-07-17 14:59:03 -0700 |
commit | 99a930b0d2b018f31474d69137f311ce3581a4c2 (patch) | |
tree | 0fc49c043991b279f3b81e15777cd6304c91054a /Documentation/RCU | |
parent | cf3620a6c7798be3395163d3bb863ab378a6aa80 (diff) | |
download | linux-99a930b0d2b018f31474d69137f311ce3581a4c2.tar.gz linux-99a930b0d2b018f31474d69137f311ce3581a4c2.tar.bz2 linux-99a930b0d2b018f31474d69137f311ce3581a4c2.zip |
documentation: Describe new expedited stall warnings
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
-rw-r--r-- | Documentation/RCU/stallwarn.txt | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 046f32637b95..efb9454875ab 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -163,6 +163,23 @@ message will be about three times the interval between the beginning of the stall and the first message. +Stall Warnings for Expedited Grace Periods + +If an expedited grace period detects a stall, it will place a message +like the following in dmesg: + + INFO: rcu_sched detected expedited stalls on CPUs: { 1 2 6 } 26009 jiffies s: 1043 + +This indicates that CPUs 1, 2, and 6 have failed to respond to a +reschedule IPI, that the expedited grace period has been going on for +26,009 jiffies, and that the expedited grace-period sequence counter is +1043. The fact that this last value is odd indicates that an expedited +grace period is in flight. + +It is entirely possible to see stall warnings from normal and from +expedited grace periods at about the same time from the same run. + + What Causes RCU CPU Stall Warnings? So your kernel printed an RCU CPU stall warning. The next question is |