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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-02-08 17:14:39 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-05-05 23:16:54 -0700
commita00e0d714fbded07a7a2254391ce9ed5a5cb9d82 (patch)
tree7c213dbf1e2561655d07749b6d689027460fb8cc /Documentation/RCU
parent0ee5623f9a6e52df90a78bd21179f8ab370e102e (diff)
downloadlinux-a00e0d714fbded07a7a2254391ce9ed5a5cb9d82.tar.gz
rcu: Remove conditional compilation for RCU CPU stall warnings
The RCU CPU stall warnings can now be controlled using the rcu_cpu_stall_suppress boot-time parameter or via the same parameter from sysfs. There is therefore no longer any reason to have kernel config parameters for this feature. This commit therefore removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter remains to allow task-stall information to be suppressed if desired. 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/00-INDEX2
-rw-r--r--Documentation/RCU/stallwarn.txt23
2 files changed, 14 insertions, 11 deletions
diff --git a/Documentation/RCU/00-INDEX b/Documentation/RCU/00-INDEX
index 71b6f500ddb..1d7a885761f 100644
--- a/Documentation/RCU/00-INDEX
+++ b/Documentation/RCU/00-INDEX
@@ -21,7 +21,7 @@ rcu.txt
RTFP.txt
- List of RCU papers (bibliography) going back to 1980.
stallwarn.txt
- - RCU CPU stall warnings (CONFIG_RCU_CPU_STALL_DETECTOR)
+ - RCU CPU stall warnings (module parameter rcu_cpu_stall_suppress)
torture.txt
- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
trace.txt
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index 862c08ef1fd..4e959208f73 100644
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -1,22 +1,25 @@
Using RCU's CPU Stall Detector
-The CONFIG_RCU_CPU_STALL_DETECTOR kernel config parameter enables
-RCU's CPU stall detector, which detects conditions that unduly delay
-RCU grace periods. The stall detector's idea of what constitutes
-"unduly delayed" is controlled by a set of C preprocessor macros:
+The rcu_cpu_stall_suppress module parameter enables RCU's CPU stall
+detector, which detects conditions that unduly delay RCU grace periods.
+This module parameter enables CPU stall detection by default, but
+may be overridden via boot-time parameter or at runtime via sysfs.
+The stall detector's idea of what constitutes "unduly delayed" is
+controlled by a set of kernel configuration variables and cpp macros:
-RCU_SECONDS_TILL_STALL_CHECK
+CONFIG_RCU_CPU_STALL_TIMEOUT
- This macro defines the period of time that RCU will wait from
- the beginning of a grace period until it issues an RCU CPU
- stall warning. This time period is normally ten seconds.
+ This kernel configuration parameter defines the period of time
+ that RCU will wait from the beginning of a grace period until it
+ issues an RCU CPU stall warning. This time period is normally
+ ten seconds.
RCU_SECONDS_TILL_STALL_RECHECK
This macro defines the period of time that RCU will wait after
issuing a stall warning until it issues another stall warning
- for the same stall. This time period is normally set to thirty
- seconds.
+ for the same stall. This time period is normally set to three
+ times the check interval plus thirty seconds.
RCU_STALL_RAT_DELAY