[PATCH 20/33] aio: give shared kioctx fields their own cachelines

From: Kent Overstreet
Date: Thu Mar 21 2013 - 12:44:47 EST


[akpm@xxxxxxxxxxxxxxxxxxxx: make reqs_active __cacheline_aligned_in_smp]
Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Zach Brown <zab@xxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mfasheh@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Asai Thambi S P <asamymuthupa@xxxxxxxxxx>
Cc: Selvan Mani <smani@xxxxxxxxxx>
Cc: Sam Bradshaw <sbradshaw@xxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 0e283ad..b71691d 100644
--- a/fs/aio.c
+++ b/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----*/
--
1.8.1.3

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