On 22.09.2021 14:29, Ian Jackson wrote: > I'm not sure, though, that I fully understand the design principles > behind non-order-0 allocations, and memory sizing, and so on. Your > earlier mail suggeted there may not be a design principle, and that > anything relying on non-order-0 atomic allocations is only working by > luck (or an embarassing excess of ram).
That's what I think, yes. During boot and in certain other specific places it may be okay to use such allocations, as long as failure leads to something non-destructive. A process (or VM) not getting created successfully _might_ be okay; a process or VM failing when it already runs is not okay. Just to give an example. The situation here falls in the latter category, at least from osstest's pov. IOW assuming that what gets tested is a goal in terms of functionality, VM creation failing when there is enough memory (just not in the right "shape") is not okay here. Or else the test was wrongly put in place. Therefore a goal I've been trying to follow in the hypervisor is to eliminate higher order allocations wherever possible. And I think the kernel wants to follow suit here. Jan
