On 1/17/23 17:13, Christoph Hellwig wrote: > On Tue, Jan 17, 2023 at 05:06:52PM +0900, Damien Le Moal wrote: >> They can, by using a large limit for "low priority" IOs. But then, these >> would still have a limit while any IO issued simultaneously without a CDL >> index specified would have no limit at all. So strictly speaking, the no >> limit IOs should be considered as even lower priority that CDL IOs with >> large limits. >> >> The other aspect here is that on ATA drives, CDL and NCQ priority cannot >> be used together. A mix of CDL and high priority commands cannot be sent >> to a device. Combining this with the above thinking, it made sense to me >> to have the CDL priority class handled the same as the RT class (as that >> is the one that maps to ATA NCQ high prio commands). > > Ok. Maybe document this a bit better in the commit log. OK. Will do. -- Damien Le Moal Western Digital Research