From: Eli Cohen <eli-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
To: Or Gerlitz <ogerlitz-hKgKHo2Ms0FWk0Htik3J/w@public.gmane.org>
Cc: Jack Morgenstein <jackm-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org>,
Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
Bharath Ramesh <bramesh-PjAqaU27lzQ@public.gmane.org>,
linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Maximum size for memory registration (ibv_reg_mr)
Date: Thu, 7 Oct 2010 12:13:16 +0200 [thread overview]
Message-ID: <20101007101316.GA9605@mtldesk30> (raw)
In-Reply-To: <4CAD9572.5060507-hKgKHo2Ms0FWk0Htik3J/w@public.gmane.org>
On Thu, Oct 07, 2010 at 11:40:02AM +0200, Or Gerlitz wrote:
> Roland Dreier wrote:
> >> max_mr_size returned by calling ibv_devinfo is 0xffffffffffffffff. Does this mean the size is unlimited?
> > It means that the query function might be returning bad data. What adapter is it?
>
> Yep, mlx4_ib_query_device does props->max_mr_size = ~0ull ...
>
> Jack, what would it take to fix that? I took a look and other settings are taken from
> dev->dev->caps.xxx where caps is of type mlx4_caps which is in turn filled @ drivers/net/mlx4/main.c
> :: mlx4_dev_cap I wasn't sure what field/computation would exactly account for later setting max_mr_size
>
It is not that trivial to calculate this value.
If you create a MR in kernel, it covers the entire address space and
the HCA does not pose any limit since you do not consume MTTs.
And if you use MTTs then the page size is a parameter in this
calculation - huge page, regular page etc.
Do leaving it as is seems to be the most accurate thing...
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next prev parent reply other threads:[~2010-10-07 10:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-24 22:12 Maximum size for memory registration (ibv_reg_mr) Bharath Ramesh
2010-09-24 22:36 ` Roland Dreier
[not found] ` <adar5giahvd.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2010-09-24 22:42 ` Bharath Ramesh
2010-09-24 22:47 ` Roland Dreier
[not found] ` <adamxr6ahd3.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2010-09-24 22:52 ` Bharath Ramesh
2010-09-24 22:57 ` Roland Dreier
[not found] ` <adaiq1uagwi.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2010-09-27 11:18 ` Tziporet Koren
2010-10-07 9:40 ` Or Gerlitz
[not found] ` <4CAD9572.5060507-hKgKHo2Ms0FWk0Htik3J/w@public.gmane.org>
2010-10-07 10:13 ` Eli Cohen [this message]
2010-10-07 11:21 ` Or Gerlitz
[not found] ` <4CADAD40.8080202-smomgflXvOZWk0Htik3J/w@public.gmane.org>
2010-10-07 11:49 ` Eli Cohen
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