Re: [LSF/MM/BPF TOPIC] Reentrant kmalloc usable from any context

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

On Thu, Mar 20, 2025 at 11:32 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> A year ago Vlastimil kicked off a discussion:
> "What's next for the SLUB allocator"
> https://lwn.net/Articles/974138/
>
> One of the proposed goals was to adopt slub allocator to use cases
> where bespoke allocators are currently used either due to
> performance requirements or context restrictions.
> bpf_mem_alloc, kretprobe's objpool, mempool were mentioned
> as initial targets. netpoll should probably be on that list too.
>
> Performance might be addressed by sheaves
> while context restrictions are more difficult to solve.
> bpf, kretprobe, netpool don't know the context where they
> might be called. Currently bpf, kretprobe handler preallocate.
> Preallocated pools pin memory to one subsystem make it
> unavailable to the rest of the kernel.
> This has to be fixed. mm subsystem needs to own, share,
> distribute the memory.
>
> Agenda for the discussion:
> - discuss and agree on problem statement
>   what is being solved, why, requirements of the solution
> - discuss pros and cons of the existing design that we
>   made a bunch of progress on
> - brainstorm next steps

Here are the slides from the talk:
https://github.com/4ast/docs/blob/main/Reentrant%20kmalloc.pdf