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authorJens Axboe <jens.axboe@oracle.com>2008-09-13 20:26:01 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 08:56:09 +0200
commitc7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 (patch)
treeecc3d2517b3471ccc35d4cb4e3b48d4b57205061 /include/linux/elevator.h
parent18887ad910e56066233a07fd3cfb2fa11338b782 (diff)
block: add support for IO CPU affinity
This patch adds support for controlling the IO completion CPU of either all requests on a queue, or on a per-request basis. We export a sysfs variable (rq_affinity) which, if set, migrates completions of requests to the CPU that originally submitted it. A bio helper (bio_set_completion_cpu()) is also added, so that queuers can ask for completion on that specific CPU. In testing, this has been show to cut the system time by as much as 20-40% on synthetic workloads where CPU affinity is desired. This requires a little help from the architecture, so it'll only work as designed for archs that are using the new generic smp helper infrastructure. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/elevator.h')
-rw-r--r--include/linux/elevator.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 639624b55fbe..bb791c311a56 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -173,15 +173,15 @@ enum {
#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
/*
- * Hack to reuse the donelist list_head as the fifo time holder while
+ * Hack to reuse the csd.list list_head as the fifo time holder while
* the request is in the io scheduler. Saves an unsigned long in rq.
*/
-#define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next)
-#define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp))
+#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next)
+#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp))
#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
#define rq_fifo_clear(rq) do { \
list_del_init(&(rq)->queuelist); \
- INIT_LIST_HEAD(&(rq)->donelist); \
+ INIT_LIST_HEAD(&(rq)->csd.list); \
} while (0)
/*