netdev - Re: [PATCH v2 bpf-next 3/9] bpf: extend is_branch

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Message-ID: <CAEf4BzZZz49_6SAtgcD+jw8BMV4fGNm+Y69QcQqxpnzknqWkfw@mail.gmail.com>
Date:   Fri, 14 Jun 2019 09:38:48 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Alexei Starovoitov <ast@...nel.org>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andriin@...com>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Kernel Team <kernel-team@...com>
Subject: Re: [PATCH v2 bpf-next 3/9] bpf: extend is_branch_taken to registers

On Fri, Jun 14, 2019 at 12:26 AM Alexei Starovoitov <ast@...nel.org> wrote:
>
> This patch extends is_branch_taken() logic from JMP+K instructions
> to JMP+X instructions.
> Conditional branches are often done when src and dst registers
> contain known scalars. In such case the verifier can follow
> the branch that is going to be taken when program executes.
> That speeds up the verification and is essential feature to support
> bounded loops.
>
> Signed-off-by: Alexei Starovoitov <ast@...nel.org>
> ---
>  kernel/bpf/verifier.c | 34 +++++++++++++++++++---------------
>  1 file changed, 19 insertions(+), 15 deletions(-)
>

Acked-by: Andrii Nakryiko <andriin@...com>