On Mon, Feb 05, 2018 at 07:58:29AM +0100, Hannes Reinecke wrote: > On 02/03/2018 05:21 AM, Ming Lei wrote: > > Hi All, > > > > This patchset supports global tags which was started by Hannes originally: > > > > https://marc.info/?l=linux-block&m=149132580511346&w=2 > > > > Also inroduce 'force_blk_mq' to 'struct scsi_host_template', so that > > driver can avoid to support two IO paths(legacy and blk-mq), especially > > recent discusion mentioned that SCSI_MQ will be enabled at default soon. > > > > https://marc.info/?l=linux-scsi&m=151727684915589&w=2 > > > > With the above two changes, it should be easier to convert SCSI drivers' > > reply queue into blk-mq's hctx, then the automatic irq affinity issue can > > be solved easily, please see detailed descrption in commit log. > > > > Also drivers may require to complete request on the submission CPU > > for avoiding hard/soft deadlock, which can be done easily with blk_mq > > too. > > > > https://marc.info/?t=151601851400001&r=1&w=2 > > > > The final patch uses the introduced 'force_blk_mq' to fix virtio_scsi > > so that IO hang issue can be avoided inside legacy IO path, this issue is > > a bit generic, at least HPSA/virtio-scsi are found broken with v4.15+. > > > > Thanks > > Ming > > > > Ming Lei (5): > > blk-mq: tags: define several fields of tags as pointer > > blk-mq: introduce BLK_MQ_F_GLOBAL_TAGS > > block: null_blk: introduce module parameter of 'g_global_tags' > > scsi: introduce force_blk_mq > > scsi: virtio_scsi: fix IO hang by irq vector automatic affinity > > > > block/bfq-iosched.c | 4 +-- > > block/blk-mq-debugfs.c | 11 ++++---- > > block/blk-mq-sched.c | 2 +- > > block/blk-mq-tag.c | 67 +++++++++++++++++++++++++++++----------------- > > block/blk-mq-tag.h | 15 ++++++++--- > > block/blk-mq.c | 31 ++++++++++++++++----- > > block/blk-mq.h | 3 ++- > > block/kyber-iosched.c | 2 +- > > drivers/block/null_blk.c | 6 +++++ > > drivers/scsi/hosts.c | 1 + > > drivers/scsi/virtio_scsi.c | 59 +++------------------------------------- > > include/linux/blk-mq.h | 2 ++ > > include/scsi/scsi_host.h | 3 +++ > > 13 files changed, 105 insertions(+), 101 deletions(-) > > > Thanks Ming for picking this up. > > I'll give it a shot and see how it behaves on other hardware. Hi Hannes, Thanks for looking at it. I am working on V2, which has fixed some issues, and added your patch of 'scsi: Add template flag 'host_tagset', but causes a HPSA kernel oops. Once it is fixed, I will posted V2 out, then there will be one real example about how to use global tags for converting reply queue to blk-mq hctx. https://github.com/ming1/linux/commits/v4.15-for-next-global-tags-V2 Thanks, Ming
