Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Hannes Reinecke
On 04/04/2017 05:59 PM, Ming Lei wrote: On Tue, Apr 4, 2017 at 8:07 PM, Hannes Reinecke wrote: Hi all, as discussed recently most existing HBAs have a host-wide tagset which does not map easily onto the per-queue tagset model of block mq. This patchset implements a flag

Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Hannes Reinecke
On 04/04/2017 05:32 PM, Omar Sandoval wrote: On Tue, Apr 04, 2017 at 02:07:43PM +0200, Hannes Reinecke wrote: Hi all, as discussed recently most existing HBAs have a host-wide tagset which does not map easily onto the per-queue tagset model of block mq. This patchset implements a flag

Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Bart Van Assche
On 04/04/2017 09:00 AM, Ming Lei wrote: > Just be curious, why is multi hard queue used for this case? Are there > some real cases in SCSI? Hello Ming, Yes, there is a real need for this. Background information is available in the following e-mail thread: Arun Easi, "scsi-mq - tag# and

Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Ming Lei
On Tue, Apr 4, 2017 at 8:07 PM, Hannes Reinecke wrote: > Hi all, > > as discussed recently most existing HBAs have a host-wide tagset which > does not map easily onto the per-queue tagset model of block mq. > This patchset implements a flag BLK_MQ_F_GLOBAL_TAGS for block-mq, which >

Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Bart Van Assche
On Tue, 2017-04-04 at 08:32 -0700, Omar Sandoval wrote: > blk-mq already supports a shared tagset, and scsi-mq already uses that. > When we initialize a request queue, we add it to a tagset with > blk_mq_add_queue_set(), where we automatically mark the tagset as shared > if there is more than one

Re: [RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Omar Sandoval
On Tue, Apr 04, 2017 at 02:07:43PM +0200, Hannes Reinecke wrote: > Hi all, > > as discussed recently most existing HBAs have a host-wide tagset which > does not map easily onto the per-queue tagset model of block mq. > This patchset implements a flag BLK_MQ_F_GLOBAL_TAGS for block-mq, which >

[RFC PATCH 0/2] block,scsi: support host-wide tagset

2017-04-04 Thread Hannes Reinecke
Hi all, as discussed recently most existing HBAs have a host-wide tagset which does not map easily onto the per-queue tagset model of block mq. This patchset implements a flag BLK_MQ_F_GLOBAL_TAGS for block-mq, which enables the use of a shared tagset for all hardware queues. The second patch