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Commit 019129d5 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU 



For the short term, map synchronize_rcu_expedited() to
synchronize_rcu() for TREE_PREEMPT_RCU and to
synchronize_sched_expedited() for TREE_RCU.

Longer term, there needs to be a real expedited grace period for
TREE_PREEMPT_RCU, but candidate patches to date are considerably
more complex and intrusive.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: npiggin@suse.de
Cc: jens.axboe@oracle.com
LKML-Reference: <12555405592331-git-send-email->
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 37c72e56

include/linux/rcutree.h

+1 −5
Original line number Diff line number Diff line
@@ -76,11 +76,7 @@ static inline void __rcu_read_unlock_bh(void) 


extern void call_rcu_sched(struct rcu_head *head,

			   void (*func)(struct rcu_head *rcu));



static inline void synchronize_rcu_expedited(void)

{

	synchronize_sched_expedited();

}

extern void synchronize_rcu_expedited(void);



static inline void synchronize_rcu_bh_expedited(void)

{

kernel/rcutree_plugin.h

+21 −0
Original line number Diff line number Diff line
@@ -392,6 +392,17 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) 
}

EXPORT_SYMBOL_GPL(call_rcu);



/*

 * Wait for an rcu-preempt grace period.  We are supposed to expedite the

 * grace period, but this is the crude slow compatability hack, so just

 * invoke synchronize_rcu().

 */

void synchronize_rcu_expedited(void)

{

	synchronize_rcu();

}

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);



/*

 * Check to see if there is any immediate preemptable-RCU-related work

 * to be done.
@@ -564,6 +575,16 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) 
}

EXPORT_SYMBOL_GPL(call_rcu);



/*

 * Wait for an rcu-preempt grace period, but make it happen quickly.

 * But because preemptable RCU does not exist, map to rcu-sched.

 */

void synchronize_rcu_expedited(void)

{

	synchronize_sched_expedited();

}

EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);



/*

 * Because preemptable RCU does not exist, it never has any work to do.

 */