> > On 6/23/20 1:25 PM, John Garry wrote: > > On 11/06/2020 09:26, John Garry wrote: > >> On 11/06/2020 03:57, Ming Lei wrote: > >>> On Thu, Jun 11, 2020 at 01:29:09AM +0800, John Garry wrote: > >>>> From: Hannes Reinecke <hare@xxxxxxx> > >>>> > >>>> The function does not set the depth, but rather transitions from > >>>> shared to non-shared queues and vice versa. > >>>> So rename it to blk_mq_update_tag_set_shared() to better reflect > >>>> its purpose. > >>> > >>> It is fine to rename it for me, however: > >>> > >>> This patch claims to rename blk_mq_update_tag_set_shared(), but also > >>> change blk_mq_init_bitmap_tags's signature. > >> > >> I was going to update the commit message here, but forgot again... > >> > >>> > >>> So suggest to split this patch into two or add comment log on > >>> changing blk_mq_init_bitmap_tags(). > >> > >> I think I'll just split into 2x commits. > > > > Hi Hannes, > > > > Do you have any issue with splitting the undocumented changes into > > another patch as so: > > > No, that's perfectly fine. > > Kashyap, I've also attached an updated patch for the elevator_count patch; > if > you agree John can include it in the next version. Hannes - Patch looks good. Header does not include problem statement. How about adding below in header ? High CPU utilization on "native_queued_spin_lock_slowpath" due to lock contention is possible in mq-deadline and bfq io scheduler when nr_hw_queues is more than one. It is because kblockd work queue can submit IO from all online CPUs (through blk_mq_run_hw_queues) even though only one hctx has pending commands. Elevator callback "has_work" for mq-deadline and bfq scheduler consider pending work if there are any IOs on request queue and it does not account hctx context. I have not seen performance drop after this patch, but I will continue further testing. John - One more thing, I am working on megaraid_sas driver to provide both host_tagset = 1 and 0 option through module parameter. Kashyap > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke Teamlead Storage & Networking > hare@xxxxxxx +49 911 74053 688 > SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 > (AG Nürnberg), Geschäftsführer: Felix Imendörffer
