From: Changwoo Min <changwoo@igalia.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Shuah Khan <shuah@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, sched-ext@lists.linux.dev,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-dev@igalia.com
Subject: Re: [PATCH] selftests/bpf: Remove duplicate copies of the arena spinlock qnodes
Date: Tue, 18 Aug 2026 01:00:04 +0900 [thread overview]
Message-ID: <75bbbff2-5ea5-493d-b543-ce40d968f3cb@igalia.com> (raw)
In-Reply-To: <c9f8616b-15df-4c5a-8184-bf4d63813afb@iogearbox.net>
Hi Daniel,
On 8/17/26 6:05 PM, Daniel Borkmann wrote:
> On 8/3/26 2:18 AM, Changwoo Min wrote:
>> bpf_arena_spin_lock.h defines its 64KB qnodes array in the header, so
>> every translation unit including it emits a copy. __weak makes them all
>> resolve to one instance, but bpftool gen object merges only the symbols
>> and concatenates each input's .addr_space.1 bytes, leaving the surplus
>> copies unreferenced in the linked object.
>>
>> libarena links ten such units, so nine copies were dead weight (bytes):
>>
>> object before after
>> -----------------------------------------------------
>> .addr_space.1 in libarena.bpf.o 676200 86376
>> libarena.skel.h 2100123 892371
>> libarena_asan.skel.h 2641124 1466477
>>
>> Declare qnodes in the header and let each program define it once:
>> libarena in src/common.bpf.c, and the arena_spin_lock test beside the
>> lock it guards.
>>
>> Tested with test_progs -t arena_spin_lock and -t libarena.
>>
>> Signed-off-by: Changwoo Min <changwoo@igalia.com>
> This doesn't apply cleanly, could you respin against latest bpf-next?
Sure. I will send the v2 rebased on the HEAD of the the bpf-next tree soon.
Regards.
Changwoo Min
>
> Thanks,
> Daniel
>
next prev parent reply other threads:[~2026-08-17 16:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-03 0:18 [PATCH] selftests/bpf: Remove duplicate copies of the arena spinlock qnodes Changwoo Min
2026-08-13 4:38 ` Kumar Kartikeya Dwivedi
2026-08-17 9:05 ` Daniel Borkmann
2026-08-17 16:00 ` Changwoo Min [this message]
2026-08-17 17:14 ` Emil Tsalapatis
2026-08-17 18:05 ` Kumar Kartikeya Dwivedi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=75bbbff2-5ea5-493d-b543-ce40d968f3cb@igalia.com \
--to=changwoo@igalia.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=emil@etsalapatis.com \
--cc=jolsa@kernel.org \
--cc=kernel-dev@igalia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=sched-ext@lists.linux.dev \
--cc=shuah@kernel.org \
--cc=song@kernel.org \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox