On 2/5/18 8:20 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' and 'host_tagset' 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 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 and the > 8th patch for converting HPSA. > > 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 6th 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+. > > The 7th & 8th patch fixes HPSA's IO issue which is caused by the reply > queue selection algorithem. > > Laurence has verified that this patch makes HPSA working with the linus > tree with this patchset. Do you have any performance numbers for this patchset? I'd be curious to know how big the hit is. -- Jens Axboe
