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authorJens Axboe <jens.axboe@oracle.com>2008-12-09 08:11:22 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-12-29 08:29:50 +0100
commitabf137dd7712132ee56d5b3143c2ff61a72a5faa (patch)
tree8334f03c598343bb93340f081fcde5ba659b440b /include
parent392ddc32982a5c661dd90dd49a3cb37f1c68b782 (diff)
downloadlinux-abf137dd7712132ee56d5b3143c2ff61a72a5faa.tar.bz2
aio: make the lookup_ioctx() lockless
The mm->ioctx_list is currently protected by a reader-writer lock, so we always grab that lock on the read side for doing ioctx lookups. As the workload is extremely reader biased, turn this into an rcu hlist so we can make lookup_ioctx() lockless. Get rid of the rwlock and use a spinlock for providing update side exclusion. There's usually only 1 entry on this list, so it doesn't make sense to look into fancier data structures. Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/aio.h5
-rw-r--r--include/linux/mm_types.h5
2 files changed, 7 insertions, 3 deletions
diff --git a/include/linux/aio.h b/include/linux/aio.h
index f6b8cf99b596..b16a957030f8 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -5,6 +5,7 @@
#include <linux/workqueue.h>
#include <linux/aio_abi.h>
#include <linux/uio.h>
+#include <linux/rcupdate.h>
#include <asm/atomic.h>
@@ -183,7 +184,7 @@ struct kioctx {
/* This needs improving */
unsigned long user_id;
- struct kioctx *next;
+ struct hlist_node list;
wait_queue_head_t wait;
@@ -199,6 +200,8 @@ struct kioctx {
struct aio_ring_info ring_info;
struct delayed_work wq;
+
+ struct rcu_head rcu_head;
};
/* prototypes */
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index fe825471d5aa..9cfc9b627fdd 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -232,8 +232,9 @@ struct mm_struct {
struct core_state *core_state; /* coredumping support */
/* aio bits */
- rwlock_t ioctx_list_lock; /* aio lock */
- struct kioctx *ioctx_list;
+ spinlock_t ioctx_lock;
+ struct hlist_head ioctx_list;
+
#ifdef CONFIG_MM_OWNER
/*
* "owner" points to a task that is regarded as the canonical