aboutsummaryrefslogtreecommitdiffstats
path: root/fs/bio.c
diff options
context:
space:
mode:
authorJens Axboe <jens.axboe@oracle.com>2008-09-13 14:26:01 -0400
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 02:56:09 -0400
commitc7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 (patch)
treeecc3d2517b3471ccc35d4cb4e3b48d4b57205061 /fs/bio.c
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 'fs/bio.c')
-rw-r--r--fs/bio.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/bio.c b/fs/bio.c
index bee4deca774a..6a637b5c24b5 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -111,6 +111,7 @@ void bio_init(struct bio *bio)
111{ 111{
112 memset(bio, 0, sizeof(*bio)); 112 memset(bio, 0, sizeof(*bio));
113 bio->bi_flags = 1 << BIO_UPTODATE; 113 bio->bi_flags = 1 << BIO_UPTODATE;
114 bio->bi_comp_cpu = -1;
114 atomic_set(&bio->bi_cnt, 1); 115 atomic_set(&bio->bi_cnt, 1);
115} 116}
116 117