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| author | Jens Axboe <jens.axboe@oracle.com> | 2008-09-13 22:26:01 +0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 10:56:09 +0400 |
| commit | c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 (patch) | |
| tree | ecc3d2517b3471ccc35d4cb4e3b48d4b57205061 /block/blk-settings.c | |
| parent | 18887ad910e56066233a07fd3cfb2fa11338b782 (diff) | |
| download | linux-c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832.tar.xz | |
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 'block/blk-settings.c')
| -rw-r--r-- | block/blk-settings.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index d70692badcdb..a60e959a12c4 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -443,7 +443,7 @@ void blk_queue_update_dma_alignment(struct request_queue *q, int mask) } EXPORT_SYMBOL(blk_queue_update_dma_alignment); -static int __init blk_settings_init(void) +int __init blk_settings_init(void) { blk_max_low_pfn = max_low_pfn - 1; blk_max_pfn = max_pfn - 1; |