From: Jens Axboe on
On Mon, Mar 01 2010, Richard Kennedy wrote:
> As the comment says the initial value of last_waited is never used, so
> there is no need to initialise it with the current jiffies. Jiffies is
> hot enough without accessing it for no reason.

Applied, though it will not make a huge difference in any way.
alloc_io_context() only gets called the first time a process does IO, so
it's not a hot path.

>
> Signed-off-by: Richard Kennedy <richard(a)rsk.demon.co.uk>
> ---
> patch against 2.6.33
> compiled & tested on x86_64
>
> diff --git a/block/blk-ioc.c b/block/blk-ioc.c
> index 98e6bf6..3f65c8a 100644
> --- a/block/blk-ioc.c
> +++ b/block/blk-ioc.c
> @@ -91,7 +91,7 @@ struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
> spin_lock_init(&ret->lock);
> ret->ioprio_changed = 0;
> ret->ioprio = 0;
> - ret->last_waited = jiffies; /* doesn't matter... */
> + ret->last_waited = 0; /* doesn't matter... */
> ret->nr_batch_requests = 0; /* because this is 0 */
> INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
> INIT_HLIST_HEAD(&ret->cic_list);
>
>

--
Jens Axboe

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