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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Wed, 2 Dec 2020 18:54:46 -0800
Message-ID: <CAADnVQJThW0_5jJ=0ejjc3jh+w9_qzctqfZ-GvJrNQcKiaGYEQ@mail.gmail.com>
Subject: Re: [PATCH bpf-next v9 00/34] bpf: switch to memcg-based memory accounting
To:     Roman Gushchin <guro@fb.com>
Cc:     bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Network Development <netdev@vger.kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Kernel Team <kernel-team@fb.com>
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On Tue, Dec 1, 2020 at 1:59 PM Roman Gushchin <guro@fb.com> wrote:
>
> 5) Cryptic -EPERM is returned on exceeding the limit. Libbpf even had
>    a function to "explain" this case for users.
...
> v9:
>   - always charge the saved memory cgroup, by Daniel, Toke and Alexei
>   - added bpf_map_kzalloc()
>   - rebase and minor fixes

This looks great. Applied.
Please follow up with a change to libbpf's pr_perm_msg().
That helpful warning should stay for old kernels, but it would be
misleading for new kernels.
libbpf probably needs a feature check to make this warning conditional.

Thanks!