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

From: Divyesh Shah
Date: Thu Apr 02 2009 - 00:07:23 EST


On Wed, Mar 11, 2009 at 6:56 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> +/*
> + * elv_exit_fq_data is called before we call elevator_exit_fn. Before
> + * we ask elevator to cleanup its queues, we do the cleanup here so
> + * that all the group and idle tree references to ioq are dropped. Later
> + * during elevator cleanup, ioc reference will be dropped which will lead
> + * to removal of ioscheduler queue as well as associated ioq object.
> + */
> +void elv_exit_fq_data(struct elevator_queue *e)
> +{
> + struct elv_fq_data *efqd = &e->efqd;
> + struct request_queue *q = efqd->queue;
> +
> + if (!elv_iosched_fair_queuing_enabled(e))
> + return;
> +
> + elv_shutdown_timer_wq(e);
> +
> + spin_lock_irq(q->queue_lock);
> + /* This should drop all the idle tree references of ioq */
> + elv_free_idle_ioq_list(e);
> + spin_unlock_irq(q->queue_lock);
> +
> + elv_shutdown_timer_wq(e);
> +
> + BUG_ON(timer_pending(&efqd->idle_slice_timer));
> + io_free_root_group(e);
> +}
>

Hi Vivek,
When cleaning up the elv_fq_data and ioqs for the iogs
associated with a device on elv_exit(), I don't see any iogs except
the root group being freed. In io_disconnect_groups() you remove the
ioqs from each of the iog and move them to the root iog and then
delete the root iog. Am I missing something here or are there leftover
iogs at elv_exit?

-Divyesh
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