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authorPeter Hurley <peter@hurleysoftware.com>2013-06-15 09:36:06 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-23 16:47:08 -0700
commit809850b7a5fcc0a96d023e1171a7944c60fd5a71 (patch)
tree5c6a22458a7d756cbfe948bfb6b7d331af01610f /include/linux/tty.h
parent2cf7b67e87f0d8db025cff12b5d29c0663bbcd87 (diff)
tty: Use lockless flip buffer free list
In preparation for lockless flip buffers, make the flip buffer free list lockless. NB: using llist is not the optimal solution, as the driver and buffer work may contend over the llist head unnecessarily. However, test measurements indicate this contention is low. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/tty.h')
-rw-r--r--include/linux/tty.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 87bbaa31ebf5..5043b12f23ea 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -11,6 +11,7 @@
#include <linux/tty_flags.h>
#include <uapi/linux/tty.h>
#include <linux/rwsem.h>
+#include <linux/llist.h>
@@ -30,7 +31,10 @@
#define __DISABLED_CHAR '\0'
struct tty_buffer {
- struct tty_buffer *next;
+ union {
+ struct tty_buffer *next;
+ struct llist_node free;
+ };
int used;
int size;
int commit;
@@ -65,7 +69,7 @@ struct tty_bufhead {
spinlock_t lock;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
- struct tty_buffer *free; /* Free queue head */
+ struct llist_head free; /* Free queue head */
int memory_used; /* Buffer space used excluding
free queue */
};