| Message ID | 20180927015513.24020-1-damien.lemoal@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] block: fix deadline elevator drain for zoned block devices | expand |
On 9/26/18 7:55 PM, Damien Le Moal wrote: > When the deadline scheduler is used with a zoned block device, writes > to a zone will be dispatched one at a time. This causes the warning > message: > > deadline: forced dispatching is broken (nr_sorted=X), please report this > > to be displayed when switching to another elevator with the legacy I/O > path while write requests to a zone are being retained in the scheduler > queue. > > Prevent this message from being displayed when executing > elv_drain_elevator() for a zoned block device. __blk_drain_queue() will > loop until all writes are dispatched and completed, resulting in the > desired elevator queue drain without extensive modifications to the > deadline code itself to handle forced-dispatch calls. Dropped the previous one and added this one.
diff --git a/block/elevator.c b/block/elevator.c index 6a06b5d040e5..fae58b2f906f 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -609,7 +609,7 @@ void elv_drain_elevator(struct request_queue *q) while (e->type->ops.sq.elevator_dispatch_fn(q, 1)) ; - if (q->nr_sorted && printed++ < 10) { + if (q->nr_sorted && !blk_queue_is_zoned(q) && printed++ < 10 ) { printk(KERN_ERR "%s: forced dispatching is broken " "(nr_sorted=%u), please report this\n", q->elevator->type->elevator_name, q->nr_sorted);
When the deadline scheduler is used with a zoned block device, writes to a zone will be dispatched one at a time. This causes the warning message: deadline: forced dispatching is broken (nr_sorted=X), please report this to be displayed when switching to another elevator with the legacy I/O path while write requests to a zone are being retained in the scheduler queue. Prevent this message from being displayed when executing elv_drain_elevator() for a zoned block device. __blk_drain_queue() will loop until all writes are dispatched and completed, resulting in the desired elevator queue drain without extensive modifications to the deadline code itself to handle forced-dispatch calls. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Fixes: 8dc8146f9c92 ("deadline-iosched: Introduce zone locking support") Cc: stable@vger.kernel.org --- Changes from v2: * Move zoned block device test before 'printed' increment as suggested by Bart * Added "Fixes" tag and cc stable Changes from v1: * Fixed typo in commit message block/elevator.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)