Re: [PATCH][RFC 13/23]: Export of alloc_io_context() function

Jens Axboe
2008-12-11T13:34:55Z

On Wed, Dec 10 2008, Vladislav Bolkhovitin wrote:
> This patch exports alloc_io_context() function. For performance reasons
> SCST queues commands using a pool of IO threads. It is considerably
> better for performance (>30% increase on sequential reads) if threads in
> a pool have the same IO context. Since SCST can be built as a module,
> it needs alloc_io_context() function exported.
>
> Signed-off-by: Vladislav Bolkhovitin <vst@vlnb.net>
> ---
> block/blk-ioc.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff -upkr linux-2.6.27.2/block/blk-ioc.c linux-2.6.27.2/block/blk-ioc.c
> --- linux-2.6.27.2/block/blk-ioc.c 2008-10-10 02:13:53.000000000 +0400
> +++ linux-2.6.27.2/block/blk-ioc.c 2008-11-25 21:27:01.000000000 +0300
> @@ -105,6 +105,7 @@ struct io_context *alloc_io_context(gfp_
>
> return ret;
> }
> +EXPORT_SYMBOL(alloc_io_context);

Why is this needed, can't you just use CLONE_IO?

--
Jens Axboe