On Wednesday, October 04, 2017 11:48:27 AM Ulf Hansson wrote:

[...]

quoted

quoted

MQ code that doesn't perform and therefore we cannot switch seamlessly
to MQ.

I think that switching seamlessly to blk-mq in short/medium-term
is not possible (SCSI tried and failed to do so). The changes to
the old path are very complex and besides affecting performance
they also affect error recovery handling (which needs to be tested
properly before the switch).

Agreed, and that's why I have queued up the new Kconfig option for
enabling the blkmq path from MMC.

This seems premature - the new Kconfig option change for "mmc-mq" should
belong to the patch adding "mmc-mq" support (otherwise it may just confuse
users who enable it).

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics