D.2.7.10 Detect a Too-Long Grace Period
Keywords: perfbook_html

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D.2.7.10 Detect a Too-Long Grace Period

When the CONFIG_RCU_CPU_STALL_DETECTOR kernel parameter is specified, the record_gp_stall_check_time() function records the time and also a timestamp set three seconds into the future. If the current grace period still has not ended by that time, the check_cpu_stall() function will check for the culprit, invoking print_cpu_stall() if the current CPU is the holdout, or print_other_cpu_stall() if it is some other CPU. A two-jiffies offset helps ensure that CPUs report on themselves when possible, taking advantage of the fact that a CPU can normally do a better job of tracing its own stack than it can tracing some other CPU's stack.