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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-07-02 08:25:57 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-08-30 10:59:48 -0700 |
| commit | 77095901b895a64b6d775879b54c73472ba21e68 (patch) | |
| tree | f448aee47cd56c244ef32eb2b804959cc7ef1e20 /Documentation/RCU/stallwarn.txt | |
| parent | doc: Improve rcu_dynticks::dynticks documentation (diff) | |
| download | linux-dev-77095901b895a64b6d775879b54c73472ba21e68.tar.xz linux-dev-77095901b895a64b6d775879b54c73472ba21e68.zip | |
doc: Update removal of RCU-bh/sched update machinery
The RCU-bh update API is now defined in terms of that of RCU-bh and
RCU-sched, so this commit updates the documentation accordingly.
In addition, although RCU-sched persists in !PREEMPT kernels, in
the PREEMPT case its update API is now defined in terms of that of
RCU-preempt, so this commit also updates the documentation accordingly.
While in the area, this commit removes the documentation for the
now-obsolete synchronize_rcu_mult() and clarifies the Tasks RCU
documentation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU/stallwarn.txt')
| -rw-r--r-- | Documentation/RCU/stallwarn.txt | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index f99cf11b314b..491043fd976f 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -16,12 +16,9 @@ o A CPU looping in an RCU read-side critical section. o A CPU looping with interrupts disabled. -o A CPU looping with preemption disabled. This condition can - result in RCU-sched stalls and, if ksoftirqd is in use, RCU-bh - stalls. +o A CPU looping with preemption disabled. -o A CPU looping with bottom halves disabled. This condition can - result in RCU-sched and RCU-bh stalls. +o A CPU looping with bottom halves disabled. o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel without invoking schedule(). If the looping in the kernel is @@ -87,9 +84,9 @@ o A hardware failure. This is quite unlikely, but has occurred This resulted in a series of RCU CPU stall warnings, eventually leading the realization that the CPU had failed. -The RCU, RCU-sched, RCU-bh, and RCU-tasks implementations have CPU stall -warning. Note that SRCU does -not- have CPU stall warnings. Please note -that RCU only detects CPU stalls when there is a grace period in progress. +The RCU, RCU-sched, and RCU-tasks implementations have CPU stall warning. +Note that SRCU does -not- have CPU stall warnings. Please note that +RCU only detects CPU stalls when there is a grace period in progress. No grace period, no CPU stall warnings. To diagnose the cause of the stall, inspect the stack traces. |