diff options
Diffstat (limited to 'Documentation/RCU/stallwarn.txt')
| -rw-r--r-- | Documentation/RCU/stallwarn.txt | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 491043fd976f..1ab70c37921f 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -176,9 +176,8 @@ causing stalls, and that the stall was affecting RCU-sched. This message will normally be followed by stack dumps for each CPU. Please note that PREEMPT_RCU builds can be stalled by tasks as well as by CPUs, and that the tasks will be indicated by PID, for example, "P3421". It is even -possible for a rcu_preempt_state stall to be caused by both CPUs -and- -tasks, in which case the offending CPUs and tasks will all be called -out in the list. +possible for an rcu_state stall to be caused by both CPUs -and- tasks, +in which case the offending CPUs and tasks will all be called out in the list. CPU 2's "(3 GPs behind)" indicates that this CPU has not interacted with the RCU core for the past three grace periods. In contrast, CPU 16's "(0 @@ -206,7 +205,7 @@ handlers are no longer able to execute on this CPU. This can happen if the stalled CPU is spinning with interrupts are disabled, or, in -rt kernels, if a high-priority process is starving RCU's softirq handler. -The "fps=" shows the number of force-quiescent-state idle/offline +The "fqs=" shows the number of force-quiescent-state idle/offline detection passes that the grace-period kthread has made across this CPU since the last time that this CPU noted the beginning of a grace period. @@ -220,17 +219,18 @@ an estimate of the total number of RCU callbacks queued across all CPUs In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed for each CPU: - 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 nonlazy_posted: 25 .D + 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 Nonlazy posted: ..D The "last_accelerate:" prints the low-order 16 bits (in hex) of the jiffies counter when this CPU last invoked rcu_try_advance_all_cbs() from rcu_needs_cpu() or last invoked rcu_accelerate_cbs() from -rcu_prepare_for_idle(). The "nonlazy_posted:" prints the number -of non-lazy callbacks posted since the last call to rcu_needs_cpu(). -Finally, an "L" indicates that there are currently no non-lazy callbacks -("." is printed otherwise, as shown above) and "D" indicates that -dyntick-idle processing is enabled ("." is printed otherwise, for example, -if disabled via the "nohz=" kernel boot parameter). +rcu_prepare_for_idle(). The "Nonlazy posted:" indicates lazy-callback +status, so that an "l" indicates that all callbacks were lazy at the start +of the last idle period and an "L" indicates that there are currently +no non-lazy callbacks (in both cases, "." is printed otherwise, as +shown above) and "D" indicates that dyntick-idle processing is enabled +("." is printed otherwise, for example, if disabled via the "nohz=" +kernel boot parameter). If the grace period ends just as the stall warning starts printing, there will be a spurious stall-warning message, which will include |