Re: [PATCH v2 06/16] block: treat DMPG and SWAPIN requests as special

From: Jeff Moyer
Date: Thu May 03 2012 - 10:38:38 EST


Venkatraman S <svenkatr@xxxxxx> writes:

> From: Ilan Smith <ilan.smith@xxxxxxxxxxx>
>
> When exp_swapin and exp_dmpg are set, treat read requests
> marked with DMPG and SWAPIN as high priority and move to
> the front of the queue.
>
[...]
> + if (bio_swapin(bio) && blk_queue_exp_swapin(q)) {
> + spin_lock_irq(q->queue_lock);
> + where = ELEVATOR_INSERT_FLUSH;
> + goto get_rq;
> + }
> +
> + if (bio_dmpg(bio) && blk_queue_exp_dmpg(q)) {
> + spin_lock_irq(q->queue_lock);
> + where = ELEVATOR_INSERT_FLUSH;
> + goto get_rq;

Is ELEVATOR_INSERT_FRONT not good enough? It seems wrong to use _FLUSH,
here. If the semantics of ELEVATOR_INSERT_FLUSH are really what is
required, then perhaps we need to have another think about the naming of
these flags.

Cheers,
Jeff
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