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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Fri, 19 Apr 2024 08:49:36 -0700
Message-ID: <CAADnVQ+hPNQ3-fVj-5qt+UrT8yPavE9L7AaphsLLEKwve21P-g@mail.gmail.com>
Subject: Re: [PATCH bpf-next 17/18] bpf: add bpf_wq_start
To: Benjamin Tissoires <bentiss@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, 
	Andrii Nakryiko <andrii@kernel.org>, Martin KaFai Lau <martin.lau@linux.dev>, 
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>, 
	Yonghong Song <yonghong.song@linux.dev>, John Fastabend <john.fastabend@gmail.com>, 
	KP Singh <kpsingh@kernel.org>, Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>, 
	Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>, 
	bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, 
	"open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@vger.kernel.org>
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On Fri, Apr 19, 2024 at 8:14=E2=80=AFAM Benjamin Tissoires <bentiss@kernel.=
org> wrote:
>
>
> Honestly I just felt the patch series was big enough for a PoC and
> comparison with sleepable bpf_timer. But if we think this needs not to
> be added, I guess that works too :)

It certainly did its job to compare the two and imo bpf_wq with kfunc appro=
ach
looks cleaner overall and will be easier to extend in the long term.

I mean that we'll be adding 3 kfuncs initially:
bpf_wq_init, bpf_wq_start, bpf_wq_set_callback.

imo that's good enough to land it and get some exposure.
I'll be using it right away to refactor bpf_arena_alloc.h into
actual arena allocator for bpf progs that is not just a selftest.

I'm currently working on locks for bpf_arena.
Kumar has a patch set that adds bpf_preempt_disble kfunc and
coupled with bpf_wq we'll have all mechanisms to build
arbitrary data structures/algorithms as bpf programs.