On 05.06.2025 18:42, Roger Pau Monné wrote: > On Fri, Mar 14, 2025 at 05:24:53PM +0000, Alejandro Vallejo wrote: >> With a single global count for the claims it's easy to substract >> domain_tot_pages() from the claim so the number given in the hypercall >> is the real reservation of the domain. This is the current behaviour. >> >> However, a later patch introduces exact-node claims and those interact >> very poorly with such a scheme. Since accounting domain_tot_pages() in >> one case but not the other seems strictly worse than not accounting them >> at all (which is at least consistent), this patch stops substracting >> tot_pages from the claim and instead checks that claimed memory + >> allocated memory don't exceed max_mem. > > Hm, while I don't have any specific interest in keeping the current > behavior, XENMEM_claim_pages is part of the stable ABI (it's not a > domctl), and hence should be stable.
Is that true? It sits inside a #if defined(__XEN__) || defined(__XEN_TOOLS__) which generally de-marks unstable (tools-only) interfaces. > Note also the comment above the > definition of XENMEM_claim_pages how it states the specific behavior > that you are trying to change (and which should have been adjusted as > part of this change). This is the more important part, imo. > I have no idea why this was made a xenmem rather than a domctl > hypercall, but if you want to change the semantics I think the only > option is introducing a new hypercall. It _is_ a memory operation, and it re-uses one of the interface structs there. (Yes, none of these would technically have prevented it from being a domctl.) Jan
