Commit f9411ebe authored by Ingo Molnar's avatar Ingo Molnar
Browse files

rcu: Separate the RCU synchronization types and APIs into <linux/rcupdate_wait.h> 



So rcupdate.h is a pretty complex header, in particular it includes
<linux/completion.h> which includes <linux/wait.h> - creating a
dependency that includes <linux/wait.h> in <linux/sched.h>,
which prevents the isolation of <linux/sched.h> from the derived
<linux/wait.h> header.

Solve part of the problem by decoupling rcupdate.h from completions:
this can be done by separating out the rcu_synchronize types and APIs,
and updating their usage sites.

Since this is a mostly RCU-internal types this will not just simplify
<linux/sched.h>'s dependencies, but will make all the hundreds of
.c files that include rcupdate.h but not completions or wait.h build
faster.

( For rcutiny this means that two dependent APIs have to be uninlined,
  but that shouldn't be much of a problem as they are rare variants. )

Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 4b53a341

fs/autofs4/autofs_i.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/mutex.h>

#include <linux/spinlock.h>

#include <linux/list.h>

#include <linux/completion.h>



/* This is the range of ioctl() numbers we claim as ours */

#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY

include/linux/dcache.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/rcupdate.h>

#include <linux/lockref.h>

#include <linux/stringhash.h>

#include <linux/wait.h>



struct path;

struct vfsmount;

include/linux/rcupdate.h

+0 −40
Original line number Diff line number Diff line
@@ -40,7 +40,6 @@ 
#include <linux/cpumask.h>

#include <linux/seqlock.h>

#include <linux/lockdep.h>

#include <linux/completion.h>

#include <linux/debugobjects.h>

#include <linux/bug.h>

#include <linux/compiler.h>
@@ -226,45 +225,6 @@ void call_rcu_sched(struct rcu_head *head, 


void synchronize_sched(void);



/*

 * Structure allowing asynchronous waiting on RCU.

 */

struct rcu_synchronize {

	struct rcu_head head;

	struct completion completion;

};

void wakeme_after_rcu(struct rcu_head *head);



void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,

		   struct rcu_synchronize *rs_array);



#define _wait_rcu_gp(checktiny, ...) \

do {									\

	call_rcu_func_t __crcu_array[] = { __VA_ARGS__ };		\

	struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)];	\

	__wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array),		\

			__crcu_array, __rs_array);			\

} while (0)



#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)



/**

 * synchronize_rcu_mult - Wait concurrently for multiple grace periods

 * @...: List of call_rcu() functions for the flavors to wait on.

 *

 * This macro waits concurrently for multiple flavors of RCU grace periods.

 * For example, synchronize_rcu_mult(call_rcu, call_rcu_bh) would wait

 * on concurrent RCU and RCU-bh grace periods.  Waiting on a give SRCU

 * domain requires you to write a wrapper function for that SRCU domain's

 * call_srcu() function, supplying the corresponding srcu_struct.

 *

 * If Tiny RCU, tell _wait_rcu_gp() not to bother waiting for RCU

 * or RCU-bh, given that anywhere synchronize_rcu_mult() can be called

 * is automatically a grace period.

 */

#define synchronize_rcu_mult(...) \

	_wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)



/**

 * call_rcu_tasks() - Queue an RCU for invocation task-based grace period

 * @head: structure to be used for queueing the RCU updates.

include/linux/rcupdate_wait.h

0 → 100644
+50 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_SCHED_RCUPDATE_WAIT_H

#define _LINUX_SCHED_RCUPDATE_WAIT_H



/*

 * RCU synchronization types and methods:

 */



#include <linux/rcupdate.h>

#include <linux/completion.h>



/*

 * Structure allowing asynchronous waiting on RCU.

 */

struct rcu_synchronize {

	struct rcu_head head;

	struct completion completion;

};

void wakeme_after_rcu(struct rcu_head *head);



void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,

		   struct rcu_synchronize *rs_array);



#define _wait_rcu_gp(checktiny, ...) \

do {									\

	call_rcu_func_t __crcu_array[] = { __VA_ARGS__ };		\

	struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)];	\

	__wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array),		\

			__crcu_array, __rs_array);			\

} while (0)



#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)



/**

 * synchronize_rcu_mult - Wait concurrently for multiple grace periods

 * @...: List of call_rcu() functions for the flavors to wait on.

 *

 * This macro waits concurrently for multiple flavors of RCU grace periods.

 * For example, synchronize_rcu_mult(call_rcu, call_rcu_bh) would wait

 * on concurrent RCU and RCU-bh grace periods.  Waiting on a give SRCU

 * domain requires you to write a wrapper function for that SRCU domain's

 * call_srcu() function, supplying the corresponding srcu_struct.

 *

 * If Tiny RCU, tell _wait_rcu_gp() not to bother waiting for RCU

 * or RCU-bh, given that anywhere synchronize_rcu_mult() can be called

 * is automatically a grace period.

 */

#define synchronize_rcu_mult(...) \

	_wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)



#endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */

include/linux/rcutiny.h

+2 −9
Original line number Diff line number Diff line
@@ -53,15 +53,8 @@ static inline void cond_synchronize_sched(unsigned long oldstate) 
	might_sleep();

}



static inline void rcu_barrier_bh(void)

{

	wait_rcu_gp(call_rcu_bh);

}



static inline void rcu_barrier_sched(void)

{

	wait_rcu_gp(call_rcu_sched);

}

extern void rcu_barrier_bh(void);

extern void rcu_barrier_sched(void);



static inline void synchronize_rcu_expedited(void)

{

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