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From:   Song Liu <song@kernel.org>
Date:   Mon, 11 Apr 2022 23:11:53 -0700
Message-ID: <CAPhsuW7O3V-mQo=Vsy-Qq3ZCqYT-0Osa4+YhzsYiu-84mGYZYQ@mail.gmail.com>
Subject: Re: [PATCH v2 bpf 2/3] module: introduce module_alloc_huge
To:     Christoph Hellwig <hch@infradead.org>
Cc:     bpf <bpf@vger.kernel.org>, Linux-MM <linux-mm@kvack.org>,
        open list <linux-kernel@vger.kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        rick.p.edgecombe@intel.com, imbrenda@linux.ibm.com,
        Luis Chamberlain <mcgrof@kernel.org>
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On Mon, Apr 11, 2022 at 9:20 PM Christoph Hellwig <hch@infradead.org> 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