Messages in this thread | | | Date | Wed, 27 Mar 2024 09:52:07 +0100 | Subject | Re: [PATCH 0/3] minor fixes and supplement for ptdesc | From | David Hildenbrand <> |
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On 26.03.24 20:07, Vishal Moola wrote: > On Mon, Mar 04, 2024 at 07:07:17PM +0800, Qi Zheng wrote: >> Hi all, > > Sorry for the late review. Thanks for looking at doing some ptdesc > conversions. This patchset has the right idea and looks *mostly* fine. > >> In this series, the [PATCH 1/3] and [PATCH 2/3] are fixes for some issues >> discovered during code inspection. >> >> The [PATCH 3/3] is a supplement to ptdesc conversion in s390, I don't know >> why this is not done in the commit 6326c26c1514 ("s390: convert various pgalloc >> functions to use ptdescs"), maybe I missed something. And since I don't have an > > It's important to keep in mind the end goal of ptdescs, cleaning up much > of the struct page field misuse by standardizing their usage. s390 page > tables and gmap are similar but not the same, so the conversions require > deeper thought. > > My initial "Split ptdesc from struct page" patchset tried to focus on the > most straightforward, simple conversions in order to introduce the > descriptor and lay a foundation for future conversions - you can see some > more complicated iterations v6 and prior. > > When converting to ptdescs (and any other newer descriptors), we should > be careful about generating superficial code churn instead of using > them to solve the problems they are trying to solve.
The gmap shadow pages are page tables that are not linked into the user page tables.
I recall I raised in the past that using ptdesc from them is confusing.
-- Cheers,
David / dhildenb
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