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authorPaul E. McKenney <paul.mckenney@linaro.org>2010-11-29 21:56:39 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-05-05 23:16:54 -0700
commit12f5f524cafef3ab689929b118f2dfb8bf2be321 (patch)
tree639473556b6edf9b79e0a18d5ba58f80eea76519 /Documentation/RCU
parente59fb3120becfb36b22ddb8bd27d065d3cdca499 (diff)
downloadlinux-12f5f524cafef3ab689929b118f2dfb8bf2be321.tar.gz
rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the rcu_node structure into a single ->blkd_tasks list with ->gp_tasks and ->exp_tasks tail pointers. This is in preparation for RCU priority boosting, which will add a third dimension to the combinatorial explosion in the ->blocked_tasks[] case, but simply a third pointer in the new ->blkd_tasks case. Also update documentation to reflect blocked_tasks[] merge Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'Documentation/RCU')
-rw-r--r--Documentation/RCU/trace.txt29
1 files changed, 18 insertions, 11 deletions
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index e731ad20d16..5a704ffd0bb 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -166,14 +166,14 @@ o "gpnum" is the number of grace periods that have started. It is
The output of "cat rcu/rcuhier" looks as follows, with very long lines:
c=6902 g=6903 s=2 jfq=3 j=72c7 nfqs=13142/nfqsng=0(13142) fqlh=6
-1/1 .>. 0:127 ^0
-3/3 .>. 0:35 ^0 0/0 .>. 36:71 ^1 0/0 .>. 72:107 ^2 0/0 .>. 108:127 ^3
-3/3f .>. 0:5 ^0 2/3 .>. 6:11 ^1 0/0 .>. 12:17 ^2 0/0 .>. 18:23 ^3 0/0 .>. 24:29 ^4 0/0 .>. 30:35 ^5 0/0 .>. 36:41 ^0 0/0 .>. 42:47 ^1 0/0 .>. 48:53 ^2 0/0 .>. 54:59 ^3 0/0 .>. 60:65 ^4 0/0 .>. 66:71 ^5 0/0 .>. 72:77 ^0 0/0 .>. 78:83 ^1 0/0 .>. 84:89 ^2 0/0 .>. 90:95 ^3 0/0 .>. 96:101 ^4 0/0 .>. 102:107 ^5 0/0 .>. 108:113 ^0 0/0 .>. 114:119 ^1 0/0 .>. 120:125 ^2 0/0 .>. 126:127 ^3
+1/1 ..>. 0:127 ^0
+3/3 ..>. 0:35 ^0 0/0 ..>. 36:71 ^1 0/0 ..>. 72:107 ^2 0/0 ..>. 108:127 ^3
+3/3f ..>. 0:5 ^0 2/3 ..>. 6:11 ^1 0/0 ..>. 12:17 ^2 0/0 ..>. 18:23 ^3 0/0 ..>. 24:29 ^4 0/0 ..>. 30:35 ^5 0/0 ..>. 36:41 ^0 0/0 ..>. 42:47 ^1 0/0 ..>. 48:53 ^2 0/0 ..>. 54:59 ^3 0/0 ..>. 60:65 ^4 0/0 ..>. 66:71 ^5 0/0 ..>. 72:77 ^0 0/0 ..>. 78:83 ^1 0/0 ..>. 84:89 ^2 0/0 ..>. 90:95 ^3 0/0 ..>. 96:101 ^4 0/0 ..>. 102:107 ^5 0/0 ..>. 108:113 ^0 0/0 ..>. 114:119 ^1 0/0 ..>. 120:125 ^2 0/0 ..>. 126:127 ^3
rcu_bh:
c=-226 g=-226 s=1 jfq=-5701 j=72c7 nfqs=88/nfqsng=0(88) fqlh=0
-0/1 .>. 0:127 ^0
-0/3 .>. 0:35 ^0 0/0 .>. 36:71 ^1 0/0 .>. 72:107 ^2 0/0 .>. 108:127 ^3
-0/3f .>. 0:5 ^0 0/3 .>. 6:11 ^1 0/0 .>. 12:17 ^2 0/0 .>. 18:23 ^3 0/0 .>. 24:29 ^4 0/0 .>. 30:35 ^5 0/0 .>. 36:41 ^0 0/0 .>. 42:47 ^1 0/0 .>. 48:53 ^2 0/0 .>. 54:59 ^3 0/0 .>. 60:65 ^4 0/0 .>. 66:71 ^5 0/0 .>. 72:77 ^0 0/0 .>. 78:83 ^1 0/0 .>. 84:89 ^2 0/0 .>. 90:95 ^3 0/0 .>. 96:101 ^4 0/0 .>. 102:107 ^5 0/0 .>. 108:113 ^0 0/0 .>. 114:119 ^1 0/0 .>. 120:125 ^2 0/0 .>. 126:127 ^3
+0/1 ..>. 0:127 ^0
+0/3 ..>. 0:35 ^0 0/0 ..>. 36:71 ^1 0/0 ..>. 72:107 ^2 0/0 ..>. 108:127 ^3
+0/3f ..>. 0:5 ^0 0/3 ..>. 6:11 ^1 0/0 ..>. 12:17 ^2 0/0 ..>. 18:23 ^3 0/0 ..>. 24:29 ^4 0/0 ..>. 30:35 ^5 0/0 ..>. 36:41 ^0 0/0 ..>. 42:47 ^1 0/0 ..>. 48:53 ^2 0/0 ..>. 54:59 ^3 0/0 ..>. 60:65 ^4 0/0 ..>. 66:71 ^5 0/0 ..>. 72:77 ^0 0/0 ..>. 78:83 ^1 0/0 ..>. 84:89 ^2 0/0 ..>. 90:95 ^3 0/0 ..>. 96:101 ^4 0/0 ..>. 102:107 ^5 0/0 ..>. 108:113 ^0 0/0 ..>. 114:119 ^1 0/0 ..>. 120:125 ^2 0/0 ..>. 126:127 ^3
This is once again split into "rcu_sched" and "rcu_bh" portions,
and CONFIG_TREE_PREEMPT_RCU kernels will again have an additional
@@ -232,13 +232,20 @@ o Each element of the form "1/1 0:127 ^0" represents one struct
current grace period.
o The characters separated by the ">" indicate the state
- of the blocked-tasks lists. A "T" preceding the ">"
+ of the blocked-tasks lists. A "G" preceding the ">"
indicates that at least one task blocked in an RCU
read-side critical section blocks the current grace
- period, while a "." preceding the ">" indicates otherwise.
- The character following the ">" indicates similarly for
- the next grace period. A "T" should appear in this
- field only for rcu-preempt.
+ period, while a "E" preceding the ">" indicates that
+ at least one task blocked in an RCU read-side critical
+ section blocks the current expedited grace period.
+ A "T" character following the ">" indicates that at
+ least one task is blocked within an RCU read-side
+ critical section, regardless of whether any current
+ grace period (expedited or normal) is inconvenienced.
+ A "." character appears if the corresponding condition
+ does not hold, so that "..>." indicates that no tasks
+ are blocked. In contrast, "GE>T" indicates maximal
+ inconvenience from blocked tasks.
o The numbers separated by the ":" are the range of CPUs
served by this struct rcu_node. This can be helpful