On Mon, 2018-10-29 at 13:53 -0600, Jens Axboe wrote: +AD4 On 10/29/18 1:40 PM, Bart Van Assche wrote: +AD4 +AD4 On Mon, 2018-10-29 at 10:37 -0600, Jens Axboe wrote: +AD4 +AD4 +AD4 -static int cpu+AF8-to+AF8-queue+AF8-index(unsigned int nr+AF8-queues, const int cpu) +AD4 +AD4 +AD4 +-static int cpu+AF8-to+AF8-queue+AF8-index(struct blk+AF8-mq+AF8-queue+AF8-map +ACo-qmap, +AD4 +AD4 +AD4 +- unsigned int nr+AF8-queues, const int cpu) +AD4 +AD4 +AD4 +AHs +AD4 +AD4 +AD4 - return cpu +ACU nr+AF8-queues+ADs +AD4 +AD4 +AD4 +- return qmap-+AD4-queue+AF8-offset +- (cpu +ACU nr+AF8-queues)+ADs +AD4 +AD4 +AD4 +AH0 +AD4 +AD4 +AD4 +AD4 +AD4 +AD4 +AFs ... +AF0 +AD4 +AD4 +AD4 +AD4 +AD4 +AD4 --- a/include/linux/blk-mq.h +AD4 +AD4 +AD4 +-+-+- b/include/linux/blk-mq.h +AD4 +AD4 +AD4 +AEAAQA -78,10 +-78,11 +AEAAQA struct blk+AF8-mq+AF8-hw+AF8-ctx +AHs +AD4 +AD4 +AD4 struct blk+AF8-mq+AF8-queue+AF8-map +AHs +AD4 +AD4 +AD4 unsigned int +ACo-mq+AF8-map+ADs +AD4 +AD4 +AD4 unsigned int nr+AF8-queues+ADs +AD4 +AD4 +AD4 +- unsigned int queue+AF8-offset+ADs +AD4 +AD4 +AD4 +AH0AOw +AD4 +AD4 +AD4 +AD4 I think it's unfortunate that the blk-mq core uses the .queue+AF8-offset member but +AD4 +AD4 that mapping functions in block drivers are responsible for setting that member. +AD4 +AD4 Since the block driver mapping functions have to set blk+AF8-mq+AF8-queue+AF8-map.nr+AF8-queues, +AD4 +AD4 how about adding a loop in blk+AF8-mq+AF8-update+AF8-queue+AF8-map() that derives .queue+AF8-offset +AD4 +AD4 from .nr+AF8-queues from previous array entries? +AD4 +AD4 It's not a simple increment, so the driver has to be the one setting it. If +AD4 we end up sharing queues, for instance, then the driver will need to set +AD4 it to the start offset of that set. If you go two patches forward you +AD4 can see that exact construct. +AD4 +AD4 IOW, it's the driver that controls the offset, not the core. If sharing of hardware queues between hardware queue types is supported, what should hctx-+AD4-type be set to? Additionally, patch 5 adds code that uses hctx-+AD4-type as an array index. How can that code work if a single hardware queue can be shared by multiple hardware queue types? Thanks, Bart.
