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Commit d4efe6c5 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcu: Shrink Tiny SRCU a bit 



In Tiny SRCU, __srcu_read_lock() is a trivial function, outweighed by
its EXPORT_SYMBOL_GPL(), and on many architectures, its call sequence.
This commit therefore moves it to srcutiny.h so that it can be inlined.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 07f6e64b

include/linux/srcutiny.h

+15 −0
Original line number Diff line number Diff line
@@ -63,6 +63,21 @@ void srcu_drive_gp(struct work_struct *wp); 


void synchronize_srcu(struct srcu_struct *sp);



/*

 * Counts the new reader in the appropriate per-CPU element of the

 * srcu_struct.  Can be invoked from irq/bh handlers, but the matching

 * __srcu_read_unlock() must be in the same handler instance.  Returns an

 * index that must be passed to the matching srcu_read_unlock().

 */

static inline int __srcu_read_lock(struct srcu_struct *sp)

{

	int idx;



	idx = READ_ONCE(sp->srcu_idx);

	WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);

	return idx;

}



static inline void synchronize_srcu_expedited(struct srcu_struct *sp)

{

	synchronize_srcu(sp);

kernel/rcu/srcutiny.c

+0 −16
Original line number Diff line number Diff line
@@ -95,22 +95,6 @@ void cleanup_srcu_struct(struct srcu_struct *sp) 
}

EXPORT_SYMBOL_GPL(cleanup_srcu_struct);



/*

 * Counts the new reader in the appropriate per-CPU element of the

 * srcu_struct.  Can be invoked from irq/bh handlers, but the matching

 * __srcu_read_unlock() must be in the same handler instance.  Returns an

 * index that must be passed to the matching srcu_read_unlock().

 */

int __srcu_read_lock(struct srcu_struct *sp)

{

	int idx;



	idx = READ_ONCE(sp->srcu_idx);

	WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);

	return idx;

}

EXPORT_SYMBOL_GPL(__srcu_read_lock);



/*

 * Removes the count for the old reader from the appropriate element of

 * the srcu_struct.