2022-04-12 21:16:39

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH v2 bpf 2/3] module: introduce module_alloc_huge

On Mon, Apr 11, 2022 at 04:35:47PM -0700, Song Liu wrote:
> Introduce module_alloc_huge, which allocates huge page backed memory in
> module memory space. The primary user of this memory is bpf_prog_pack
> (multiple BPF programs sharing a huge page).

I kow I lead you downthis road first, but I wonder if we just want to
pass a flag to module_alloc instead. This avoids duplicating all the
arch overrides.


2022-04-12 22:35:25

by Song Liu

[permalink] [raw]
Subject: Re: [PATCH v2 bpf 2/3] module: introduce module_alloc_huge

On Mon, Apr 11, 2022 at 9:20 PM Christoph Hellwig <[email protected]> wrote:
>
> On Mon, Apr 11, 2022 at 04:35:47PM -0700, Song Liu wrote:
> > Introduce module_alloc_huge, which allocates huge page backed memory in
> > module memory space. The primary user of this memory is bpf_prog_pack
> > (multiple BPF programs sharing a huge page).
>
> I kow I lead you downthis road first, but I wonder if we just want to
> pass a flag to module_alloc instead. This avoids duplicating all the
> arch overrides.

I don't think we will see many archs support bpf_prog_pack, so the __weak
version might be good enough for a long time. Adding an argument to
module_alloc seems like more trouble to me.

Thanks,
Song