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[PATCH tip/core/rcu 01/16] rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL

From "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject [PATCH tip/core/rcu 01/16] rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL
Date 2015-07-18 00:30 +0200
Message-ID <pNmiK-1Y8-7@gated-at.bofh.it> (permalink)
References <pNmiJ-1Y8-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

The RCU_USER_QS Kconfig parameter is now just a synonym for NO_HZ_FULL,
so this commit eliminates RCU_USER_QS, replacing all uses with NO_HZ_FULL.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 include/linux/rcupdate.h | 4 ++--
 init/Kconfig             | 9 ---------
 kernel/rcu/tree.c        | 8 ++++----
 kernel/time/Kconfig      | 2 --
 4 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 4cf5f51b4c9c..237f7b8d38ba 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -309,7 +309,7 @@ static inline void rcu_sysrq_end(void)
 }
 #endif /* #else #ifdef CONFIG_RCU_STALL_COMMON */
 
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
 void rcu_user_enter(void);
 void rcu_user_exit(void);
 #else
@@ -317,7 +317,7 @@ static inline void rcu_user_enter(void) { }
 static inline void rcu_user_exit(void) { }
 static inline void rcu_user_hooks_switch(struct task_struct *prev,
 					 struct task_struct *next) { }
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
 
 #ifdef CONFIG_RCU_NOCB_CPU
 void rcu_init_nohz(void);
diff --git a/init/Kconfig b/init/Kconfig
index af09b4fb43d2..fdeff4ab5995 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -538,15 +538,6 @@ config RCU_STALL_COMMON
 config CONTEXT_TRACKING
        bool
 
-config RCU_USER_QS
-	bool
-	help
-	  This option sets hooks on kernel / userspace boundaries and
-	  puts RCU in extended quiescent state when the CPU runs in
-	  userspace. It means that when a CPU runs in userspace, it is
-	  excluded from the global RCU state machine and thus doesn't
-	  try to keep the timer tick on for RCU.
-
 config CONTEXT_TRACKING_FORCE
 	bool "Force context tracking"
 	depends on CONTEXT_TRACKING
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 65137bc28b2b..8b5dd8ba9495 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -701,7 +701,7 @@ void rcu_idle_enter(void)
 }
 EXPORT_SYMBOL_GPL(rcu_idle_enter);
 
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
 /**
  * rcu_user_enter - inform RCU that we are resuming userspace.
  *
@@ -714,7 +714,7 @@ void rcu_user_enter(void)
 {
 	rcu_eqs_enter(1);
 }
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
 
 /**
  * rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle
@@ -828,7 +828,7 @@ void rcu_idle_exit(void)
 }
 EXPORT_SYMBOL_GPL(rcu_idle_exit);
 
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
 /**
  * rcu_user_exit - inform RCU that we are exiting userspace.
  *
@@ -839,7 +839,7 @@ void rcu_user_exit(void)
 {
 	rcu_eqs_exit(1);
 }
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
 
 /**
  * rcu_irq_enter - inform RCU that current CPU is entering irq away from idle
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 579ce1b929af..4008d9f95dd7 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -92,12 +92,10 @@ config NO_HZ_FULL
 	depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
 	# We need at least one periodic CPU for timekeeping
 	depends on SMP
-	# RCU_USER_QS dependency
 	depends on HAVE_CONTEXT_TRACKING
 	# VIRT_CPU_ACCOUNTING_GEN dependency
 	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
 	select NO_HZ_COMMON
-	select RCU_USER_QS
 	select RCU_NOCB_CPU
 	select VIRT_CPU_ACCOUNTING_GEN
 	select IRQ_WORK
-- 
1.8.1.5

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Thread

[PATCH tip/core/rcu 01/16] rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 15/16] scripts: Make checkpatch.pl warn on expedited RCU grace periods "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
    Re: [PATCH tip/core/rcu 15/16] scripts: Make checkpatch.pl warn on  expedited RCU grace periods Joe Perches <joe@perches.com> - 2015-07-18 00:40 +0200
  [PATCH tip/core/rcu 03/16] rcu: Change return type to bool "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 10/16] rcu: Make rcu_is_watching() really notrace "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 07/16] rcu: Fix obsolete priority-boosting comment "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 12/16] rcu: Fix backwards RCU_LOCKDEP_WARN() in synchronize_rcu_tasks() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 11/16] rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 02/16] rcu: Deinline rcu_read_lock_sched_held() if DEBUG_LOCK_ALLOC "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 05/16] rcu: Hide RCU_NOCB_CPU behind RCU_EXPERT "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 06/16] rcu: Use WRITE_ONCE in RCU_INIT_POINTER "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 04/16] rcu: Add RCU-sched flavors of get-state and cond-sync "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 14/16] rcu: update MAINTAINERS entry "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 16/16] rcu: Don't disable CPU hotplug during OOM notifiers "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 09/16] cpu: Wait for RCU grace periods concurrently "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200
  [PATCH tip/core/rcu 13/16] rcu: Clarify CONFIG_RCU_EQS_DEBUG help text "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-07-18 00:30 +0200

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