Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 31 Mar 2023 19:36:29 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <olsajiri@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Hao Luo <haoluo@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, bpf@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Stanislav Fomichev <sdf@google.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Namhyung Kim <namhyung@gmail.com>,
        Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object
Message-ID: <ZCcoLcncAVeKOZRL@casper.infradead.org>
References: <20230316170149.4106586-1-jolsa@kernel.org>
 <ZBNTMZjEoETU9d8N@casper.infradead.org>
 <ZBV3beyxYhKv/kMp@krava>
 <ZBXV3crf/wX5D9lo@casper.infradead.org>
 <ZBsihOYrMCILT2cI@kernel.org>
 <CAEf4BzakHh3qm2JBsWE8qnMmZMeM7w5vZGneKAsLM_vktPbc9g@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAEf4BzakHh3qm2JBsWE8qnMmZMeM7w5vZGneKAsLM_vktPbc9g@mail.gmail.com>
Precedence: bulk

On Fri, Mar 31, 2023 at 11:19:45AM -0700, Andrii Nakryiko wrote:
> On Wed, Mar 22, 2023 at 8:45 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> > Having said that, it seems there will be no extra memory overhead at
> > least for a fedora:36 x86_64 kernel:
> 
> Makes sense to me as well. Whatever the solution, as long as it's
> usable from NMI contexts would be fine for the purposes of fetching
> build ID. It would be good to hear from folks that are opposing adding
> a pointer field to struct file whether they prefer this way instead?

Still no.  While it may not take up any room right now, this will
surely not be the last thing added to struct file.  When something
which is genuinely useful needs to be added, that person should
not have to sort out your mess first,

NAK now, NAK tomorrow, NAK forever.  Al told you how you could do it
without trampling on core data structures.