On Thu, Feb 24, 2022 at 05:06:40PM +0800, Wang Jianchao (Kuaishou) wrote:
> This patch makes blk-rq-qos policies pluggable as following,
> (1) Add code to maintain the rq_qos_ops. A rq-qos policy need to
> register itself with rq_qos_register(). The original enum
> rq_qos_id will be removed in following patch. They will use
> a dynamic id maintained by rq_qos_ida.
> (2) Add .init callback into rq_qos_ops. We use it to initialize the
> resource.
> (3) Add /sys/block/x/queue/qos
> We can use '+name' or "-name" to open or close the blk-rq-qos
> policy.
This sunds like most of these should be separate patches.
> {
> struct request_queue *q = rqos->q;
> - const char *dir_name = rq_qos_id_to_name(rqos->id);
> + const char *dir_name;
> +
> + if (rqos->ops->name)
> + dir_name = rqos->ops->name;
> + else
> + dir_name = rq_qos_id_to_name(rqos->id);
Plase split out a patch to add the name to all the ops and remove
rq_qos_id_to_name, which can be at the beginning of the series.
> + spin_lock_irq(&q->rqos_lock);
> + pos = q->rq_qos;
> + if (pos) {
> + while (pos->next)
> + pos = pos->next;
> + pos->next = rqos;
> + } else {
> + q->rq_qos = rqos;
> + }
I think another really useful prep patch would be to switch the queue
linkage to use a hlist_head instead of all this open coded list
manipulation.
> + rqos = rq_qos_by_name(q, qosname);
> + if ((buf[0] == '+' && rqos)) {
> + ret = -EEXIST;
> + goto out;
> + }
> +
> + if ((buf[0] == '-' && !rqos)) {
These two conditionals have pretty odd extra braces.
