linux-kernel - Re: [PATCH v5 bpf-next 0/7] bpf_prog

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Date:   Fri, 21 Jan 2022 01:06:33 +0000
From:   Song Liu <songliubraving@...com>
To:     Peter Ziljstra <peterz@...radead.org>
CC:     bpf <bpf@...r.kernel.org>, Networking <netdev@...r.kernel.org>,
        "Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Kernel Team <Kernel-team@...com>, X86 ML <x86@...nel.org>
Subject: Re: [PATCH v5 bpf-next 0/7] bpf_prog_pack allocator

Hi Peter,

> On Jan 20, 2022, at 11:12 AM, Song Liu <song@...nel.org> wrote:
> 
> Changes v4 => v5:
> 1. Do not use atomic64 for bpf_jit_current. (Alexei)
> 
> Changes v3 => v4:
> 1. Rename text_poke_jit() => text_poke_copy(). (Peter)
> 2. Change comment style. (Peter)
> 
> Changes v2 => v3:
> 1. Fix tailcall.
> 
> Changes v1 => v2:
> 1. Use text_poke instead of writing through linear mapping. (Peter)
> 2. Avoid making changes to non-x86_64 code.
> 
> Most BPF programs are small, but they consume a page each. For systems
> with busy traffic and many BPF programs, this could also add significant
> pressure to instruction TLB.
> 
> This set tries to solve this problem with customized allocator that pack
> multiple programs into a huge page.
> 
> Patches 1-5 prepare the work. Patch 6 contains key logic of the allocator.
> Patch 7 uses this allocator in x86_64 jit compiler.
> 
> Song Liu (7):
>  x86/Kconfig: select HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP
>  bpf: use bytes instead of pages for bpf_jit_[charge|uncharge]_modmem
>  bpf: use size instead of pages in bpf_binary_header
>  bpf: add a pointer of bpf_binary_header to bpf_prog
>  x86/alternative: introduce text_poke_copy
>  bpf: introduce bpf_prog_pack allocator
>  bpf, x86_64: use bpf_prog_pack allocator

Could you please share your feedback for and/or ack this set?

Thanks,
Song