From: Huang Ying <ying.huang@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
ying.huang@intel.com, Peter Zijlstra <peterz@infradead.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [PATCH -mm -v2 4/5] llist, Return whether list is empty before adding in llist_add
Date: Thu, 8 Sep 2011 14:00:45 +0800 [thread overview]
Message-ID: <1315461646-1379-5-git-send-email-ying.huang@intel.com> (raw)
In-Reply-To: <1315461646-1379-1-git-send-email-ying.huang@intel.com>
This is needed by irq_work. And because list_add_xxx functions are
inline, this can be optimized out if not needed by callers.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
include/linux/llist.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -148,8 +148,10 @@ static inline bool llist_empty(const str
* llist_add - add a new entry
* @new: new entry to be added
* @head: the head for your lock-less list
+ *
+ * Return whether list is empty before adding.
*/
-static inline void llist_add(struct llist_node *new, struct llist_head *head)
+static inline bool llist_add(struct llist_node *new, struct llist_head *head)
{
struct llist_node *entry, *old_entry;
@@ -164,6 +166,8 @@ static inline void llist_add(struct llis
break;
cpu_relax();
}
+
+ return old_entry == NULL;
}
/**
@@ -171,8 +175,10 @@ static inline void llist_add(struct llis
* @new_first: first entry in batch to be added
* @new_last: last entry in batch to be added
* @head: the head for your lock-less list
+ *
+ * Return whether list is empty before adding.
*/
-static inline void llist_add_batch(struct llist_node *new_first,
+static inline bool llist_add_batch(struct llist_node *new_first,
struct llist_node *new_last,
struct llist_head *head)
{
@@ -189,6 +195,8 @@ static inline void llist_add_batch(struc
break;
cpu_relax();
}
+
+ return old_entry == NULL;
}
/**
next prev parent reply other threads:[~2011-09-08 6:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-08 6:00 [PATCH -mm -v2 0/5] irq_work, Use llist in irq_work Huang Ying
2011-09-08 6:00 ` [PATCH -mm -v2 1/5] llist, Make all llist functions inline Huang Ying
2011-09-08 6:00 ` [PATCH -mm -v2 2/5] llist, Define macro to check NMI safe cmpxchg Huang Ying
2011-09-08 6:00 ` [PATCH -mm -v2 3/5] llist, Move cpu_relax after cmpxchg Huang Ying
2011-09-08 6:00 ` Huang Ying [this message]
2011-09-08 6:00 ` [PATCH -mm -v2 5/5] irq_work, Use llist in irq_work Huang Ying
2011-09-12 14:05 ` [PATCH 6/5] llist: Add llist_next() Peter Zijlstra
2011-09-12 14:05 ` [PATCH 7/5] sched: Convert to use llist Peter Zijlstra
2011-09-12 14:05 ` [PATCH 8/5] llist: Remove cpu_relax() usage in cmpxchg loops Peter Zijlstra
2011-09-12 14:23 ` Andi Kleen
2011-09-12 14:23 ` Peter Zijlstra
2011-09-12 14:47 ` Mathieu Desnoyers
2011-09-12 15:09 ` Peter Zijlstra
2011-09-12 15:24 ` Peter Zijlstra
2011-09-12 16:38 ` Andi Kleen
2011-09-12 18:53 ` Peter Zijlstra
2011-09-12 14:26 ` Avi Kivity
2011-09-12 14:32 ` Peter Zijlstra
2011-09-13 11:43 ` Avi Kivity
2011-09-13 14:22 ` Peter Zijlstra
2011-09-13 14:51 ` Avi Kivity
2011-09-13 14:53 ` Peter Zijlstra
2011-09-12 14:06 ` [PATCH -mm -v2 0/5] irq_work, Use llist in irq_work Peter Zijlstra
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