aio: give shared kioctx fields their own cachelines

[akpm@linux-foundation.org: make reqs_active __cacheline_aligned_in_smp]
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/aio.c

@@ -67,13 +67,6 @@ struct kioctx {
 	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.
@@ -92,19 +85,29 @@ struct kioctx {
 	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----*/