Commit b3e627d3 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Paul E. McKenney
Browse files

rcu: Make PREEMPT_RCU be a modifier to TREE_RCU 



Currently PREEMPT_RCU and TREE_RCU are mutually exclusive Kconfig
options.  But PREEMPT_RCU actually specifies a kind of TREE_RCU,
namely a preemptible TREE_RCU. This commit therefore makes PREEMPT_RCU
be a modifer to the TREE_RCU Kconfig option.  This has the benefit of
simplifying several of the #if expressions that formerly needed to
check both, but now need only check one or the other.

Signed-off-by: default avatarLai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: default avatarLai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 03bd2983

include/linux/rcupdate.h

+2 −2
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ do { \ 
 * TREE_RCU and rcu_barrier_() primitives in TINY_RCU.

 */



#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)

#if defined(CONFIG_TREE_RCU)

#include <linux/rcutree.h>

#elif defined(CONFIG_TINY_RCU)

#include <linux/rcutiny.h>
@@ -601,7 +601,7 @@ do { \ 
 * read-side critical section that would block in a !PREEMPT kernel.

 * But if you want the full story, read on!

 *

 * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU),

 * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU),

 * it is illegal to block while in an RCU read-side critical section.

 * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION

 * kernel builds, RCU read-side critical sections may be preempted,

include/trace/events/rcu.h

+2 −2
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ TRACE_EVENT(rcu_utilization, 
	TP_printk("%s", __entry->s)

);



#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)

#if defined(CONFIG_TREE_RCU)



/*

 * Tracepoint for grace-period events.  Takes a string identifying the
@@ -432,7 +432,7 @@ TRACE_EVENT_RCU(rcu_fqs, 
		  __entry->cpu, __entry->qsevent)

);



#endif /* #if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) */

#endif /* #if defined(CONFIG_TREE_RCU) */



/*

 * Tracepoint for dyntick-idle entry/exit events.  These take a string

kernel/rcu/Kconfig

+7 −6
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ menu "RCU Subsystem" 


config TREE_RCU

	bool

	default y if !PREEMPTION && SMP

	default y if SMP

	help

	  This option selects the RCU implementation that is

	  designed for very large SMP system with hundreds or
@@ -17,6 +17,7 @@ config TREE_RCU 
config PREEMPT_RCU

	bool

	default y if PREEMPTION

	select TREE_RCU

	help

	  This option selects the RCU implementation that is

	  designed for very large SMP systems with hundreds or
@@ -78,7 +79,7 @@ config TASKS_RCU 
	  user-mode execution as quiescent states.



config RCU_STALL_COMMON

	def_bool ( TREE_RCU || PREEMPT_RCU )

	def_bool TREE_RCU

	help

	  This option enables RCU CPU stall code that is common between

	  the TINY and TREE variants of RCU.  The purpose is to allow
@@ -86,13 +87,13 @@ config RCU_STALL_COMMON 
	  making these warnings mandatory for the tree variants.



config RCU_NEED_SEGCBLIST

	def_bool ( TREE_RCU || PREEMPT_RCU || TREE_SRCU )

	def_bool ( TREE_RCU || TREE_SRCU )



config RCU_FANOUT

	int "Tree-based hierarchical RCU fanout value"

	range 2 64 if 64BIT

	range 2 32 if !64BIT

	depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT

	depends on TREE_RCU && RCU_EXPERT

	default 64 if 64BIT

	default 32 if !64BIT

	help
@@ -112,7 +113,7 @@ config RCU_FANOUT_LEAF 
	int "Tree-based hierarchical RCU leaf-level fanout value"

	range 2 64 if 64BIT

	range 2 32 if !64BIT

	depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT

	depends on TREE_RCU && RCU_EXPERT

	default 16

	help

	  This option controls the leaf-level fanout of hierarchical
@@ -187,7 +188,7 @@ config RCU_BOOST_DELAY 


config RCU_NOCB_CPU

	bool "Offload RCU callback processing from boot-selected CPUs"

	depends on TREE_RCU || PREEMPT_RCU

	depends on TREE_RCU

	depends on RCU_EXPERT || NO_HZ_FULL

	default n

	help

kernel/rcu/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -9,6 +9,5 @@ obj-$(CONFIG_TINY_SRCU) += srcutiny.o 
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o

obj-$(CONFIG_RCU_PERF_TEST) += rcuperf.o

obj-$(CONFIG_TREE_RCU) += tree.o

obj-$(CONFIG_PREEMPT_RCU) += tree.o

obj-$(CONFIG_TINY_RCU) += tiny.o

obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o

kernel/rcu/rcu.h

+1 −1
Original line number Diff line number Diff line
@@ -454,7 +454,7 @@ enum rcutorture_type { 
	INVALID_RCU_FLAVOR

};



#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)

#if defined(CONFIG_TREE_RCU)

void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,

			    unsigned long *gp_seq);

void do_trace_rcu_torture_read(const char *rcutorturename,

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