Re: [PATCH 2/8] scsi-mq: Add support for multiple hardware queues

2014-09-26 Thread Ming Lei 
On Sat, Sep 20, 2014 at 2:05 AM, Sagi Grimberg sa...@dev.mellanox.co.il wrote:
 On 9/19/2014 3:57 PM, Bart Van Assche wrote:
 Allow a SCSI LLD to declare how many hardware queues it supports
 by setting Scsi_Host.nr_hw_queues before calling scsi_add_host().

 Note: it is assumed that each hardware queue has a queue depth of
 shost-can_queue. In other words, the total queue depth per host
 is (number of hardware queues) * (shost-can_queue).

 Signed-off-by: Bart Van Assche bvanass...@acm.org
 Cc: Christoph Hellwig h...@lst.de
 ---
   drivers/scsi/scsi_lib.c  | 2 +-
   include/scsi/scsi_host.h | 4 
   2 files changed, 5 insertions(+), 1 deletion(-)

 diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
 index d837dc1..b0b6117 100644
 --- a/drivers/scsi/scsi_lib.c
 +++ b/drivers/scsi/scsi_lib.c
 @@ -2071,7 +2071,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)

   memset(shost-tag_set, 0, sizeof(shost-tag_set));
   shost-tag_set.ops = scsi_mq_ops;
 - shost-tag_set.nr_hw_queues = 1;
 + shost-tag_set.nr_hw_queues = shost-nr_hw_queues ? : 1;
   shost-tag_set.queue_depth = shost-can_queue;
   shost-tag_set.cmd_size = cmd_size;
   shost-tag_set.numa_node = NUMA_NO_NODE;
 diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
 index ba20347..0a867d9 100644
 --- a/include/scsi/scsi_host.h
 +++ b/include/scsi/scsi_host.h
 @@ -638,6 +638,10 @@ struct Scsi_Host {
   short unsigned int sg_prot_tablesize;
   unsigned int max_sectors;
   unsigned long dma_boundary;
 + /*
 + * In scsi-mq mode, the number of hardware queues supported by the LLD.
 + */
 + unsigned nr_hw_queues;
   /*
   * Used to assign serial numbers to the cmds.
   * Protected by the host lock.


 I think this patch should be squashed with passing LLD hctx patch (in
 whatever form it ends up).

I suggest to apply this patch and related scsi-mq multi hw-queue
enablement patches first, so that any scsi drivers capable of
multi hw-queue can go without waiting for passing hctx
patches which may take a bit long since lots of drivers are involved,
as Jens said, the mapping from req to hctx is quite cheap.


Thanks,
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Re: [PATCH 2/8] scsi-mq: Add support for multiple hardware queues

2014-09-26 Thread Bart Van Assche 

On 26/09/2014 5:08, Ming Lei wrote:


I suggest to apply this patch and related scsi-mq multi hw-queue
enablement patches first, so that any scsi drivers capable of
multi hw-queue can go without waiting for passing hctx
patches which may take a bit long since lots of drivers are involved,
as Jens said, the mapping from req to hctx is quite cheap.


Hello Ming,

This week I have been traveling. I hope to find more time next week or 
the week after next week to rework this patch series and to address the 
feedback I have received from you, Jens, Christoph and Sagi.


Bart.
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Re: [PATCH 2/8] scsi-mq: Add support for multiple hardware queues

2014-09-19 Thread Sagi Grimberg 
On 9/19/2014 3:57 PM, Bart Van Assche wrote:
 Allow a SCSI LLD to declare how many hardware queues it supports
 by setting Scsi_Host.nr_hw_queues before calling scsi_add_host().

 Note: it is assumed that each hardware queue has a queue depth of
 shost-can_queue. In other words, the total queue depth per host
 is (number of hardware queues) * (shost-can_queue).

 Signed-off-by: Bart Van Assche bvanass...@acm.org
 Cc: Christoph Hellwig h...@lst.de
 ---
   drivers/scsi/scsi_lib.c  | 2 +-
   include/scsi/scsi_host.h | 4 
   2 files changed, 5 insertions(+), 1 deletion(-)

 diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
 index d837dc1..b0b6117 100644
 --- a/drivers/scsi/scsi_lib.c
 +++ b/drivers/scsi/scsi_lib.c
 @@ -2071,7 +2071,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)

   memset(shost-tag_set, 0, sizeof(shost-tag_set));
   shost-tag_set.ops = scsi_mq_ops;
 - shost-tag_set.nr_hw_queues = 1;
 + shost-tag_set.nr_hw_queues = shost-nr_hw_queues ? : 1;
   shost-tag_set.queue_depth = shost-can_queue;
   shost-tag_set.cmd_size = cmd_size;
   shost-tag_set.numa_node = NUMA_NO_NODE;
 diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
 index ba20347..0a867d9 100644
 --- a/include/scsi/scsi_host.h
 +++ b/include/scsi/scsi_host.h
 @@ -638,6 +638,10 @@ struct Scsi_Host {
   short unsigned int sg_prot_tablesize;
   unsigned int max_sectors;
   unsigned long dma_boundary;
 + /*
 + * In scsi-mq mode, the number of hardware queues supported by the LLD.
 + */
 + unsigned nr_hw_queues;
   /*
   * Used to assign serial numbers to the cmds.
   * Protected by the host lock.


I think this patch should be squashed with passing LLD hctx patch (in
whatever form it ends up).
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Re: [PATCH 2/8] scsi-mq: Add support for multiple hardware queues

2014-09-19 Thread Christoph Hellwig 
On Fri, Sep 19, 2014 at 09:05:53PM +0300, Sagi Grimberg wrote:
 I think this patch should be squashed with passing LLD hctx patch (in
 whatever form it ends up).

Agreed.
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