Commit 25bca50e authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

block: improve ioprio class description comment 



In include/usapi/linux/ioprio.h, change the ioprio class enum comment
to remove the outdated reference to CFQ and mention BFQ and mq-deadline
instead. Also document the high priority NCQ command use for RT class
IOs directed at ATA drives that support NCQ priority.

Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210811033702.368488-3-damien.lemoal@wdc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a680dd72

include/uapi/linux/ioprio.h

+6 −4
Original line number Diff line number Diff line
@@ -13,10 +13,12 @@ 
#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)



/*

 * These are the io priority groups as implemented by CFQ. RT is the realtime

 * class, it always gets premium service. BE is the best-effort scheduling

 * class, the default for any process. IDLE is the idle scheduling class, it

 * is only served when no one else is using the disk.

 * These are the io priority groups as implemented by the BFQ and mq-deadline

 * schedulers. RT is the realtime class, it always gets premium service. For

 * ATA disks supporting NCQ IO priority, RT class IOs will be processed using

 * high priority NCQ commands. BE is the best-effort scheduling class, the

 * default for any process. IDLE is the idle scheduling class, it is only

 * served when no one else is using the disk.

 */

enum {

	IOPRIO_CLASS_NONE,