diff options
| author | Jens Axboe <jens.axboe@oracle.com> | 2008-09-13 20:26:01 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:09 +0200 |
| commit | c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 (patch) | |
| tree | ecc3d2517b3471ccc35d4cb4e3b48d4b57205061 /include/linux/blkdev.h | |
| parent | 18887ad910e56066233a07fd3cfb2fa11338b782 (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/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 10aa46c8f17..93204bf7b29 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -17,6 +17,7 @@ #include <linux/module.h> #include <linux/stringify.h> #include <linux/bsg.h> +#include <linux/smp.h> #include <asm/scatterlist.h> @@ -139,7 +140,8 @@ enum rq_flag_bits { */ struct request { struct list_head queuelist; - struct list_head donelist; + struct call_single_data csd; + int cpu; struct request_queue *q; @@ -420,6 +422,7 @@ struct request_queue #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */ #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */ #define QUEUE_FLAG_NOMERGES 10 /* disable merge attempts */ +#define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */ static inline int queue_is_locked(struct request_queue *q) { |