Re: [PATCH 6/8] cfq-iosched: move cfq_group determination from cfq_find_alloc_queue() to cfq_get_queue()

From: Jeff Moyer
Date: Tue Jun 09 2015 - 10:32:48 EST


Tejun Heo <tj@xxxxxxxxxx> writes:

> This is necessary for making async cfq_cgroups per-cfq_group instead
> of per-cfq_data. While this change makes cfq_get_queue() perform RCU
> locking and look up cfq_group even when it reuses async queue, the
> extra overhead is extremely unlikely to be noticeable given that this
> is already sitting behind cic->cfqq[] cache and the overall cost of
> cfq operation.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
> Cc: Arianna Avanzini <avanzini.arianna@xxxxxxxxx>

Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
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