From: Jim Harris <jim.harris@samsung.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>
Subject: Re: [PATCH] cxl/region: use region (not root decoder) granularity for calculations
Date: Wed, 25 Oct 2023 15:48:36 +0000 [thread overview]
Message-ID: <ZTk40lwwUPDjswqx@ubuntu> (raw)
In-Reply-To: <6538796bcd4cf_72583294d3@dwillia2-xfh.jf.intel.com.notmuch>
On Tue, Oct 24, 2023 at 07:11:55PM -0700, Dan Williams wrote:
>
> So the reason I went looking for the interleave_granularity_store()
> version of the patch was only because this one when viewed in isolation
> has the problem that the root-decoder granularity can only be overridden
> to the region granularity when root-decoder interleave ways is 1.
>
> Is this assumed safe because interleave_granularity_store() is enforcing
> that regions must match root-decoder granularity? If "yes", then this
> likely wants a "/* See interleave_granularity_store() ... */" like
> comment to describe why this override is safe, if "no" then I am missing
> something.
The answer is "yes". I'll add a comment in the v2.
> What I liked about the idea of putting this in
> interleave_granularity_store() is keeping all the simplification
> shortcuts and commentary in one place, in case the region interleave !=
> root-decoder interleave ban is lifted.
>
> I don't mind doing this fixup in cxl_port_setup_targets(), but would
> want the comment per above.
I also debated this after identifiying the 1-line code fix. This new
approach avoids the whole "effective_granularity" special case for the
root decoders for now at least. It would need to be revisited if we
support interleaved host-bridges with region IG < root IG in the future.
next prev parent reply other threads:[~2023-10-25 15:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20231004230826uscas1p2f7957bf868a609211271e30ad8ff551f@uscas1p2.samsung.com>
2023-10-04 23:08 ` [PATCH] cxl: set root decoder granularity based on region params Jim Harris
2023-10-05 1:18 ` Dan Williams
2023-10-05 16:52 ` Jim Harris
2023-10-05 18:08 ` Dan Williams
2023-10-25 0:55 ` Dan Williams
2023-10-25 1:33 ` Jim Harris
2023-10-25 1:58 ` Dan Williams
2023-10-06 16:21 ` [PATCH] cxl/region: use region (not root decoder) granularity for calculations Jim Harris
2023-10-25 2:11 ` Dan Williams
2023-10-25 15:48 ` Jim Harris [this message]
2023-10-25 15:48 ` [PATCH v2] " Jim Harris
2023-10-26 0:11 ` Dan Williams
2023-10-26 17:11 ` Dan Williams
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