All of lore.kernel.org
 help / color / mirror / Atom feed
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;
 }
 
 /**

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1315461646-1379-5-git-send-email-ying.huang@intel.com \
    --to=ying.huang@intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=andi@firstfloor.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=peterz@infradead.org \
    --subject='Re: [PATCH -mm -v2 4/5] llist, Return whether list is empty before adding in llist_add' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.