Re: [PATCH 02/10] Common flat fair queuing code in elevaotor layer

From: Gui Jianfeng
Date: Thu Mar 19 2009 - 02:29:18 EST


Vivek Goyal wrote:
...
> +
> +int elv_init_ioq(struct elevator_queue *eq, struct io_queue *ioq,
> + void *sched_queue, int ioprio_class, int ioprio,
> + int is_sync)
> +{
> + struct elv_fq_data *efqd = &eq->efqd;
> + struct io_group *iog = io_lookup_io_group_current(efqd->queue);
> +
> + RB_CLEAR_NODE(&ioq->entity.rb_node);
> + atomic_set(&ioq->ref, 0);
> + ioq->efqd = efqd;
> + ioq->entity.budget = efqd->elv_slice[is_sync];
> + elv_ioq_set_ioprio_class(ioq, ioprio_class);
> + elv_ioq_set_ioprio(ioq, ioprio);
> + ioq->pid = current->pid;

Hi Vivek,

If we are using a scheduler other than cfq, IOW single ioq is used.
that storing a pid to the ioq makes no sense, it just stores the first
serviced task.

> + ioq->sched_queue = sched_queue;
> + elv_mark_ioq_idle_window(ioq);
> + bfq_init_entity(&ioq->entity, iog);
> + return 0;
> +}
> +EXPORT_SYMBOL(elv_init_ioq);
...
> +
> +extern int elv_slice_idle;
> +extern int elv_slice_async;
> +
> +/* Logging facilities. */
> +#define elv_log_ioq(efqd, ioq, fmt, args...) \
> + blk_add_trace_msg((efqd)->queue, "%d" fmt, (ioq)->pid, ##args)

Maybe we need to use current->pid instead, for ioq->pid is not valid
sometimes.

> +
> +#define elv_log(efqd, fmt, args...) \
> + blk_add_trace_msg((efqd)->queue, "" fmt, ##args)
> +
> +#define ioq_sample_valid(samples) ((samples) > 80)
> +


--
Regards
Gui Jianfeng

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