Hi, On Friday, October 28, 2016 09:30:07 AM Jens Axboe wrote: > On 10/28/2016 03:32 AM, Linus Walleij wrote: > > The patch to enable MQ looks like this: > > https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-stericsson.git/commit/?h=mmc-mq&id=8f79b527e2e854071d8da019451da68d4753f71d > > BTW, another viable "hack" for the depth issue would be to expose more > than one hardware queue. It's meant to map to a distinct submission > region in the hardware, but there's nothing stopping the driver from > using it differently. Might not be cleaner than just increasing the > queue depth on a single queue, though. Yes, I'm already considering this for rewritten version of my patch set as it may also help with performance when compared to non blk-mq case. Significant amount of time is spent on DMA map/unmap operations on ARM MMC hosts and I would like to do these DMA (un)mapping-s in parallel for two (or more) requests to check whether it helps the performance (hopefully the cache controller doesn't serialize these operations). BTW I'm following the discussion and still would like to help with getting blk-mq work for MMC. I'm just quite busy with other things at the moment. > That still won't solve the issue of lying about it and causing IO > scheduler confusion, of course. > > Also, 4.8 and newer have support for BLK_MQ_F_BLOCKING, if you need to > block in ->queue_rq(). That could eliminate the need to offload to a > kthread manually. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
