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Re: [PATCH 0/7] x86: Address Space Isolation, part 1: per-domain area mapping rework
- To: George Dunlap <gwd@xxxxxxxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Fri, 21 Aug 2026 10:45:28 +0200
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- Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger@xxxxxxxxxxxxxx>, Teddy Astie <teddy.astie@xxxxxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Michal Orzel <michal.orzel@xxxxxxx>, Julien Grall <julien@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Fri, 21 Aug 2026 08:45:34 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 20.08.2026 19:43, George Dunlap wrote:
> One point reviewers may want to look at specifically: patch 1 changes
> where the per-domain page-tables are allocated from, and its commit
> message discusses the (minor) NUMA-placement consequence.
While I don't recall which recent patch (series) it was, I can't very well
say "no new xenheap allocations please" there without also saying so here.
I've read over patch 1's description, and while it tries to justify this
accordingly, I still remain concerned. I think we simply have to accept
the mapping overhead, to avoid allocating from a pool which - over time -
is representing a decreasing portion of total memory systems have (on
average, and not even considering systems with extremely sparse memory
layouts, and with perhaps PDX compression not doing good enough to
compensate).
Jan
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