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llist: Make some llist functions inline

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Because llist code will be used in performance critical scheduler
code path, make llist_add() and llist_del_all() inline to avoid
function calling overhead and related 'glue' overhead.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1315461646-1379-2-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Huang Ying
2011-09-08 14:00:42 +08:00
committed by Ingo Molnar
parent 22f92bacbe
commit 1230db8e15
5 changed files with 59 additions and 53 deletions
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64
include/linux/llist.h
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@@ -37,8 +37,28 @@
* architectures that don't have NMI-safe cmpxchg implementation, the
* list can NOT be used in NMI handler. So code uses the list in NMI
* handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
*
* Copyright 2010,2011 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <asm/system.h>
#include <asm/processor.h>
struct llist_head {
struct llist_node *first;
};
@@ -113,14 +133,46 @@ static inline void init_llist_head(struct llist_head *list)
* test whether the list is empty without deleting something from the
* list.
*/
static inline int llist_empty(const struct llist_head *head)
static inline bool llist_empty(const struct llist_head *head)
{
return ACCESS_ONCE(head->first) == NULL;
}
void llist_add(struct llist_node *new, struct llist_head *head);
void llist_add_batch(struct llist_node *new_first, struct llist_node *new_last,
struct llist_head *head);
struct llist_node *llist_del_first(struct llist_head *head);
struct llist_node *llist_del_all(struct llist_head *head);
/**
* llist_add - add a new entry
* @new: new entry to be added
* @head: the head for your lock-less list
*/
static inline void llist_add(struct llist_node *new, struct llist_head *head)
{
struct llist_node *entry, *old_entry;
#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
BUG_ON(in_nmi());
#endif
entry = head->first;
do {
old_entry = entry;
new->next = entry;
cpu_relax();
} while ((entry = cmpxchg(&head->first, old_entry, new)) != old_entry);
}
/**
* llist_del_all - delete all entries from lock-less list
* @head: the head of lock-less list to delete all entries
*
* If list is empty, return NULL, otherwise, delete all entries and
* return the pointer to the first entry. The order of entries
* deleted is from the newest to the oldest added one.
*/
static inline struct llist_node *llist_del_all(struct llist_head *head)
{
#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
BUG_ON(in_nmi());
#endif
return xchg(&head->first, NULL);
}
#endif /* LLIST_H */