aio: give shared kioctx fields their own cachelines

[[e-mail]: make reqs_active __cacheline_aligned_in_smp]
Signed-off-by: Kent Overstreet <[e-mail]>
Cc: Zach Brown <[e-mail]>
Cc: Felipe Balbi <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Mark Fasheh <[e-mail]>
Cc: Joel Becker <[e-mail]>
Cc: Rusty Russell <[e-mail]>
Cc: Jens Axboe <[e-mail]>
Cc: Asai Thambi S P <[e-mail]>
Cc: Selvan Mani <[e-mail]>
Cc: Sam Bradshaw <[e-mail]>
Cc: Jeff Moyer <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: Benjamin LaHaise <[e-mail]>
Reviewed-by: "Theodore Ts'o" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/aio.c

···
 	unsigned long		user_id;
 	struct hlist_node	list;
 
-	wait_queue_head_t	wait;
-
-	spinlock_t		ctx_lock;
-
-	atomic_t		reqs_active;
-	struct list_head	active_reqs;	/* used for cancellation */
-
 	/*
 	 * This is what userspace passed to io_setup(), it's not used for
 	 * anything but counting against the global max_reqs quota.
···
 	struct page		**ring_pages;
 	long			nr_pages;
 
+	struct rcu_head		rcu_head;
+	struct work_struct	rcu_work;
+
+	struct {
+		atomic_t	reqs_active;
+	} ____cacheline_aligned_in_smp;
+
+	struct {
+		spinlock_t	ctx_lock;
+		struct list_head active_reqs;	/* used for cancellation */
+	} ____cacheline_aligned_in_smp;
+
 	struct {
 		struct mutex	ring_lock;
-	} ____cacheline_aligned;
+		wait_queue_head_t wait;
+	} ____cacheline_aligned_in_smp;
 
 	struct {
 		unsigned	tail;
 		spinlock_t	completion_lock;
-	} ____cacheline_aligned;
+	} ____cacheline_aligned_in_smp;
 
 	struct page		*internal_pages[AIO_RING_PAGES];
-
-	struct rcu_head		rcu_head;
-	struct work_struct	rcu_work;
 };
 
 /*------ sysctl variables----*/