On 7/24/2015 9:40 PM, Steve Wise wrote:
-----Original Message-----
From: Jason Gunthorpe [mailto:jgunthorpe@xxxxxxxxxxxxxxxxxxxx]
Sent: Friday, July 24, 2015 11:41 AM
To: Steve Wise
Cc: dledford@xxxxxxxxxx; infinipath@xxxxxxxxx; sagig@xxxxxxxxxxxx; ogerlitz@xxxxxxxxxxxx; roid@xxxxxxxxxxxx; linux-
rdma@xxxxxxxxxxxxxxx; eli@xxxxxxxxxxxx; target-devel@xxxxxxxxxxxxxxx; linux-nfs@xxxxxxxxxxxxxxx; bfields@xxxxxxxxxxxx
Subject: Re: [PATCH V6 1/9] RDMA/iser: Limit sg tablesize and max_sectors to device fastreg max depth
On Fri, Jul 24, 2015 at 11:18:21AM -0500, Steve Wise wrote:
Currently the sg tablesize, which dictates fast register page list
depth to use, does not take into account the limits of the rdma device.
So adjust it once we discover the device fastreg max depth limit. Also
adjust the max_sectors based on the resulting sg tablesize.
Huh. How does this relate to the max_page_list_len argument:
struct ib_mr *ib_alloc_fast_reg_mr(struct ib_pd *pd, int max_page_list_len)
Shouldn't max_fast_reg_page_list_len be checked during the above?
Ie does this still make sense:
drivers/infiniband/ulp/iser/iser_verbs.c: desc->data_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE + 1);
?
The only ULP that checks this is SRP, so basically, all our ULPs are
probably quietly broken? cxgb3 has a limit of 10 (!?!?!!)
Yea seems like some drivers need to enforce this in ib_alloc_fast_reg_mr() as well as ib_alloc_fast_reg_page_list(), and ULPs need
to not exceed the device max.
I will fix iser to limit the mr and page_list allocation based on the device max.
Steve, I have a patch that addresses this in the pipe.
The patch is support for up to 8MB transfer size for 4.3 (hopefully).
So no need for you to tackle this.
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