Re: [PATCH 001 of 4] md: Define backing_dev_info.congested_fn forraid0 and linear

From: Andrew Morton
Date: Tue Aug 29 2006 - 01:57:30 EST


On Tue, 29 Aug 2006 15:39:24 +1000
NeilBrown <neilb@xxxxxxx> wrote:

>
> Each backing_dev needs to be able to report whether it is congested,
> either by modulating BDI_*_congested in ->state, or by
> defining a ->congested_fn.
> md/raid did neither of these. This patch add a congested_fn
> which simply checks all component devices to see if they are
> congested.
>
> Signed-off-by: Neil Brown <neilb@xxxxxxx>
>
> +static int linear_congested(void *data, int bits)
> +{
> + mddev_t *mddev = data;
> + linear_conf_t *conf = mddev_to_conf(mddev);
> + int i, ret = 0;
> +
> + for (i = 0; i < mddev->raid_disks && !ret ; i++) {
> + request_queue_t *q = bdev_get_queue(conf->disks[i].rdev->bdev);
> + ret |= bdi_congested(&q->backing_dev_info, bits);

nit: `ret = ' would suffice here.

> +static int raid0_congested(void *data, int bits)
> +{
> + mddev_t *mddev = data;
> + raid0_conf_t *conf = mddev_to_conf(mddev);
> + mdk_rdev_t **devlist = conf->strip_zone[0].dev;
> + int i, ret = 0;
> +
> + for (i = 0; i < mddev->raid_disks && !ret ; i++) {
> + request_queue_t *q = bdev_get_queue(devlist[i]->bdev);
> +
> + ret |= bdi_congested(&q->backing_dev_info, bits);

And here.

> + }
> + return ret;
> +}
> +
>
> static int create_strip_zones (mddev_t *mddev)
> {
> @@ -236,6 +251,8 @@ static int create_strip_zones (mddev_t *
> mddev->queue->unplug_fn = raid0_unplug;
>
> mddev->queue->issue_flush_fn = raid0_issue_flush;
> + mddev->queue->backing_dev_info.congested_fn = raid0_congested;
> + mddev->queue->backing_dev_info.congested_data = mddev;
>
> printk("raid0: done.\n");
> return 0;
-
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