Now that RCU Tasks Trace being defined in terms of SRCU-fast,
the rcupdate.rcu_task_ipi_delay kernel boot parameter and the
TASKS_TRACE_RCU_READ_MB Kconfig option are no longer used. This commit
therefore removes them.
Signed-off-by: Paul E. McKenney <paul...@kernel.org>
Cc: Andrii Nakryiko <and...@kernel.org>
Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: <b...@vger.kernel.org>
---
.../admin-guide/kernel-parameters.txt | 7 -------
kernel/rcu/Kconfig | 18 ------------------
kernel/rcu/tasks.h | 5 -----
.../selftests/rcutorture/configs/rcu/TRACE01 | 1 -
.../selftests/rcutorture/configs/rcu/TRACE02 | 1 -
5 files changed, 32 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 54d31a5e46e1cf..40fc198bed4db9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6078,13 +6078,6 @@
dynamically) adjusted. This parameter is intended
for use in testing.
- rcupdate.rcu_task_ipi_delay= [KNL]
- Set time in jiffies during which RCU tasks will
- avoid sending IPIs, starting with the beginning
- of a given grace period. Setting a large
- number avoids disturbing real-time workloads,
- but lengthens grace periods.
-
rcupdate.rcu_task_lazy_lim= [KNL]
Number of callbacks on a given CPU that will
cancel laziness on that CPU. Use -1 to disable
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index eeaa1cd47c6c4c..73a6cc364628b5 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -313,24 +313,6 @@ config RCU_NOCB_CPU_CB_BOOST
Say Y here if you want to set RT priority for offloading kthreads.
Say N here if you are building a !PREEMPT_RT kernel and are unsure.
-config TASKS_TRACE_RCU_READ_MB
- bool "Tasks Trace RCU readers use memory barriers in user and idle"
- depends on RCU_EXPERT && TASKS_TRACE_RCU
- default PREEMPT_RT || NR_CPUS < 8
- help
- Use this option to further reduce the number of IPIs sent
- to CPUs executing in userspace or idle during tasks trace
- RCU grace periods. Given that a reasonable setting of
- the rcupdate.rcu_task_ipi_delay kernel boot parameter
- eliminates such IPIs for many workloads, proper setting
- of this Kconfig option is important mostly for aggressive
- real-time installations and for battery-powered devices,
- hence the default chosen above.
-
- Say Y here if you hate IPIs.
- Say N here if you hate read-side memory barriers.
- Take the default if you are unsure.
-
config RCU_LAZY
bool "RCU callback lazy invocation functionality"
depends on RCU_NOCB_CPU
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index a3c16e65e16812..833e180db744f2 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -161,11 +161,6 @@ static void tasks_rcu_exit_srcu_stall(struct timer_list
*unused);
static DEFINE_TIMER(tasks_rcu_exit_srcu_stall_timer,
tasks_rcu_exit_srcu_stall);
#endif
-/* Avoid IPIing CPUs early in the grace period. */
-#define RCU_TASK_IPI_DELAY (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) ? HZ /
2 : 0)
-static int rcu_task_ipi_delay __read_mostly = RCU_TASK_IPI_DELAY;
-module_param(rcu_task_ipi_delay, int, 0644);
-
/* Control stall timeouts. Disable with <= 0, otherwise jiffies till stall. */
#define RCU_TASK_BOOT_STALL_TIMEOUT (HZ * 30)
#define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10)
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
b/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
index 85b407467454a2..18efab346381a4 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
@@ -10,5 +10,4 @@ CONFIG_PROVE_LOCKING=n
#CHECK#CONFIG_PROVE_RCU=n
CONFIG_FORCE_TASKS_TRACE_RCU=y
#CHECK#CONFIG_TASKS_TRACE_RCU=y
-CONFIG_TASKS_TRACE_RCU_READ_MB=y
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRACE02
b/tools/testing/selftests/rcutorture/configs/rcu/TRACE02
index 9003c56cd76484..8da390e8282977 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TRACE02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TRACE02
@@ -9,6 +9,5 @@ CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
CONFIG_FORCE_TASKS_TRACE_RCU=y
#CHECK#CONFIG_TASKS_TRACE_RCU=y
-CONFIG_TASKS_TRACE_RCU_READ_MB=n
CONFIG_RCU_EXPERT=y
CONFIG_DEBUG_OBJECTS=y
--
2.40.1
