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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-05-12 10:08:07 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-05-19 23:25:29 +0200 |
| commit | 80d02085d99039b3b7f3a73c8896226b0cb1ba07 (patch) | |
| tree | c310902423ecb00effadcb59c60cbf118d4037cb /Documentation/RCU | |
| parent | net,rcu: convert call_rcu(prl_entry_destroy_rcu) to kfree (diff) | |
| download | linux-80d02085d99039b3b7f3a73c8896226b0cb1ba07.tar.xz linux-80d02085d99039b3b7f3a73c8896226b0cb1ba07.zip | |
Revert "rcu: Decrease memory-barrier usage based on semi-formal proof"
This reverts commit e59fb3120becfb36b22ddb8bd27d065d3cdca499.
This reversion was due to (extreme) boot-time slowdowns on SPARC seen by
Yinghai Lu and on x86 by Ingo
.
This is a non-trivial reversion due to intervening commits.
Conflicts:
Documentation/RCU/trace.txt
kernel/rcutree.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/trace.txt | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt index 8173cec473aa..c078ad48f7a1 100644 --- a/Documentation/RCU/trace.txt +++ b/Documentation/RCU/trace.txt @@ -99,11 +99,18 @@ o "qp" indicates that RCU still expects a quiescent state from o "dt" is the current value of the dyntick counter that is incremented when entering or leaving dynticks idle state, either by the - scheduler or by irq. This number is even if the CPU is in - dyntick idle mode and odd otherwise. The number after the first - "/" is the interrupt nesting depth when in dyntick-idle state, - or one greater than the interrupt-nesting depth otherwise. - The number after the second "/" is the NMI nesting depth. + scheduler or by irq. The number after the "/" is the interrupt + nesting depth when in dyntick-idle state, or one greater than + the interrupt-nesting depth otherwise. + + This field is displayed only for CONFIG_NO_HZ kernels. + +o "dn" is the current value of the dyntick counter that is incremented + when entering or leaving dynticks idle state via NMI. If both + the "dt" and "dn" values are even, then this CPU is in dynticks + idle mode and may be ignored by RCU. If either of these two + counters is odd, then RCU must be alert to the possibility of + an RCU read-side critical section running on this CPU. This field is displayed only for CONFIG_NO_HZ kernels. |