From 0eafa46823971b4c368f4cdf19f1d081c4ee52b7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 28 Aug 2014 15:00:30 -0700 Subject: rcu: Remove CONFIG_RCU_CPU_STALL_VERBOSE The CONFIG_RCU_CPU_STALL_VERBOSE Kconfig parameter causes preemptible RCU's CPU stall warnings to dump out any preempted tasks that are blocking the current RCU grace period. This information is useful, and the default has been CONFIG_RCU_CPU_STALL_VERBOSE=y for some years. It is therefore time for this commit to remove this Kconfig parameter, so that future kernel builds will always act as if CONFIG_RCU_CPU_STALL_VERBOSE=y. Signed-off-by: Paul E. McKenney --- Documentation/RCU/stallwarn.txt | 6 ------ 1 file changed, 6 deletions(-) (limited to 'Documentation/RCU/stallwarn.txt') diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index ef5a2fd4ff70..1560efbcc759 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -26,12 +26,6 @@ CONFIG_RCU_CPU_STALL_TIMEOUT Stall-warning messages may be enabled and disabled completely via /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress. -CONFIG_RCU_CPU_STALL_VERBOSE - - This kernel configuration parameter causes the stall warning to - also dump the stacks of any tasks that are blocking the current - RCU-preempt grace period. - CONFIG_RCU_CPU_STALL_INFO This kernel configuration parameter causes the stall warning to -- cgit v1.2.3 From 28f6569ab7d036cd4ee94c26bb76dc1b3f3fc056 Mon Sep 17 00:00:00 2001 From: Pranith Kumar Date: Mon, 22 Sep 2014 14:00:48 -0400 Subject: rcu: Remove redundant TREE_PREEMPT_RCU config option PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU has been removed. This patch removes TREE_PREEMPT_RCU and uses PREEMPT_RCU config option in its place. Signed-off-by: Pranith Kumar Signed-off-by: Paul E. McKenney --- Documentation/RCU/stallwarn.txt | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation/RCU/stallwarn.txt') diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index ef5a2fd4ff70..783e0720994d 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -77,7 +77,7 @@ This message indicates that CPU 5 detected that it was causing a stall, and that the stall was affecting RCU-sched. This message will normally be followed by a stack dump of the offending CPU. On TREE_RCU kernel builds, RCU and RCU-sched are implemented by the same underlying mechanism, -while on TREE_PREEMPT_RCU kernel builds, RCU is instead implemented +while on PREEMPT_RCU kernel builds, RCU is instead implemented by rcu_preempt_state. On the other hand, if the offending CPU fails to print out a stall-warning @@ -89,7 +89,7 @@ INFO: rcu_bh_state detected stalls on CPUs/tasks: { 3 5 } (detected by 2, 2502 j This message indicates that CPU 2 detected that CPUs 3 and 5 were both causing stalls, and that the stall was affecting RCU-bh. This message will normally be followed by stack dumps for each CPU. Please note that -TREE_PREEMPT_RCU builds can be stalled by tasks as well as by CPUs, +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 @@ -205,10 +205,10 @@ o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that is running at a higher priority than the RCU softirq threads. This will prevent RCU callbacks from ever being invoked, - and in a CONFIG_TREE_PREEMPT_RCU kernel will further prevent + and in a CONFIG_PREEMPT_RCU kernel will further prevent RCU grace periods from ever completing. Either way, the system will eventually run out of memory and hang. In the - CONFIG_TREE_PREEMPT_RCU case, you might see stall-warning + CONFIG_PREEMPT_RCU case, you might see stall-warning messages. o A hardware or software issue shuts off the scheduler-clock -- cgit v1.2.3