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Diffstat (limited to 'Documentation/RCU/stallwarn.txt')
| -rw-r--r-- | Documentation/RCU/stallwarn.txt | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 862c08ef1fde..4e959208f736 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -1,22 +1,25 @@ Using RCU's CPU Stall Detector -The CONFIG_RCU_CPU_STALL_DETECTOR kernel config parameter enables -RCU's CPU stall detector, which detects conditions that unduly delay -RCU grace periods. The stall detector's idea of what constitutes -"unduly delayed" is controlled by a set of C preprocessor macros: +The rcu_cpu_stall_suppress module parameter enables RCU's CPU stall +detector, which detects conditions that unduly delay RCU grace periods. +This module parameter enables CPU stall detection by default, but +may be overridden via boot-time parameter or at runtime via sysfs. +The stall detector's idea of what constitutes "unduly delayed" is +controlled by a set of kernel configuration variables and cpp macros: -RCU_SECONDS_TILL_STALL_CHECK +CONFIG_RCU_CPU_STALL_TIMEOUT - This macro defines the period of time that RCU will wait from - the beginning of a grace period until it issues an RCU CPU - stall warning. This time period is normally ten seconds. + This kernel configuration parameter defines the period of time + that RCU will wait from the beginning of a grace period until it + issues an RCU CPU stall warning. This time period is normally + ten seconds. RCU_SECONDS_TILL_STALL_RECHECK This macro defines the period of time that RCU will wait after issuing a stall warning until it issues another stall warning - for the same stall. This time period is normally set to thirty - seconds. + for the same stall. This time period is normally set to three + times the check interval plus thirty seconds. RCU_STALL_RAT_DELAY |