linux-kernel - RE: [PATCH bpf-next 1/3] bpf: add batched ops support for percpu array

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Message-ID: <606bbc7db9d66_d464620822@john-XPS-13-9370.notmuch>
Date:   Mon, 05 Apr 2021 18:42:21 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Pedro Tammela <pctammela@...il.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, Shuah Khan <shuah@...nel.org>,
        Pedro Tammela <pctammela@...atatu.com>,
        David Verbeiren <david.verbeiren@...sares.net>,
        Matthieu Baerts <matthieu.baerts@...sares.net>,
        "(open list:BPF \\(Safe dynamic programs and tools\\))" 
        <netdev@...r.kernel.org>,
        bpf@...r.kernel.org (open list:BPF \(Safe dynamic programs and tools\)),
        "(open list:BPF \\(Safe dynamic programs and tools\\) open list)" 
        <linux-kernel@...r.kernel.org>,
        "(open list:BPF \\(Safe dynamic programs and tools\\) open list open
        list:KERNEL SELFTEST FRAMEWORK)" <linux-kselftest@...r.kernel.org> (open
        list:BPF \(Safe dynamic programs and tools\) open list open list:KERNEL
        SELFTEST FRAMEWORK)
Cc:     Jamal Hadi Salim <jhs@...atatu.com>
Subject: RE: [PATCH bpf-next 1/3] bpf: add batched ops support for percpu
 array

Pedro Tammela wrote:
> Suggested-by: Jamal Hadi Salim <jhs@...atatu.com>
> Signed-off-by: Pedro Tammela <pctammela@...atatu.com>
> ---

A commit message describing some of the change details and a note it uses
the for-each cpu copies (same as normal syscall on percpu map) and not the
per-cpu ones would be nice. I at least had to go and check the generic_map*
batch operations.

Also something about why generic_map_delete_batch is omitted?

>  kernel/bpf/arraymap.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
> index 463d25e1e67e..3c4105603f9d 100644
> --- a/kernel/bpf/arraymap.c
> +++ b/kernel/bpf/arraymap.c
> @@ -698,6 +698,8 @@ const struct bpf_map_ops percpu_array_map_ops = {
>  	.map_delete_elem = array_map_delete_elem,
>  	.map_seq_show_elem = percpu_array_map_seq_show_elem,
>  	.map_check_btf = array_map_check_btf,
> +	.map_lookup_batch = generic_map_lookup_batch,
> +	.map_update_batch = generic_map_update_batch,
>  	.map_set_for_each_callback_args = map_set_for_each_callback_args,
>  	.map_for_each_callback = bpf_for_each_array_elem,
>  	.map_btf_name = "bpf_array",
> -- 
> 2.25.1
>