On 4/18/23 22:07, Christoph Hellwig wrote:
deadline_add_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
{
struct rb_root *root = deadline_rb_root(per_prio, rq);
+ struct request **next_rq __maybe_unused;
elv_rb_add(root, rq);
+#ifdef CONFIG_BLK_DEV_ZONED
+ next_rq = &per_prio->next_rq[rq_data_dir(rq)];
+ if (*next_rq == NULL || !blk_queue_is_zoned(rq->q))
+ return;
+ /*
+ * If a request got requeued or requests have been submitted out of
+ * order, make sure that per zone the request with the lowest LBA is
+ * submitted first.
+ */
+ if (blk_rq_pos(rq) < blk_rq_pos(*next_rq) &&
+ blk_rq_zone_no(rq) == blk_rq_zone_no(*next_rq))
+ *next_rq = rq;
+#endif
Please key move this into a helper only called when blk_queue_is_zoned
is true.
Hi Christoph,
I'm looking into an alternative, namely to remove the next_rq member
from struct dd_per_prio and instead to do the following:
* Track the offset (blk_rq_pos()) of the most recently dispatched
request ("latest_pos").
* Where the next_rq member is read, look up the request that comes after
latest_pos in the RB-tree. This should require an effort that is similar
to updating next_rq after having dispatched a request.
With this approach the code quoted above and that is surrounded with
#ifdef/#endif will disappear.
Bart.
