tty: Avoid false-sharing flip buffer ptrs

Separate the head and tail ptrs to avoid cache-line contention
(so called 'false-sharing') between concurrent threads.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-06-15 09:36:12 -04:00 committed by Greg Kroah-Hartman
parent d7a68be4f2
commit 8c1fb49ba1

View file

@ -65,13 +65,13 @@ static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
struct tty_bufhead {
struct tty_buffer *head; /* Queue head */
struct work_struct work;
struct mutex flush_mutex;
struct tty_buffer sentinel;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
struct llist_head free; /* Free queue head */
atomic_t memory_used; /* In-use buffers excluding free list */
struct tty_buffer *tail; /* Active buffer */
};
/*
* When a break, frame error, or parity error happens, these codes are