Received-SPF: pass (google.com: domain of linux-kernel+bounces-202210-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To: Jesper Dangaard Brouer <hawk@kernel.org>, Sebastian Andrzej Siewior
 <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, "David S. Miller"
 <davem@davemloft.net>, Boqun Feng <boqun.feng@gmail.com>, Daniel Borkmann
 <daniel@iogearbox.net>, Eric Dumazet <edumazet@google.com>, Frederic
 Weisbecker <frederic@kernel.org>, Ingo Molnar <mingo@redhat.com>, Jakub
 Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, Peter
 Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>,
 Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>, Alexei
 Starovoitov <ast@kernel.org>, Andrii Nakryiko <andrii@kernel.org>, Eduard
 Zingerman <eddyz87@gmail.com>, Hao Luo <haoluo@google.com>, Jiri Olsa
 <jolsa@kernel.org>, John Fastabend <john.fastabend@gmail.com>, KP Singh
 <kpsingh@kernel.org>, Martin KaFai Lau <martin.lau@linux.dev>, Song Liu
 <song@kernel.org>, Stanislav Fomichev <sdf@google.com>, Yonghong Song
 <yonghong.song@linux.dev>, bpf@vger.kernel.org
Subject: Re: [PATCH v3 net-next 14/15] net: Reference bpf_redirect_info via
 task_struct on PREEMPT_RT.
In-Reply-To: <9afab1bb-43d6-4f17-b45d-7f4569d9db70@kernel.org>
References: <20240529162927.403425-1-bigeasy@linutronix.de>
 <20240529162927.403425-15-bigeasy@linutronix.de> <87y17sfey6.fsf@toke.dk>
 <20240531103807.QjzIOAOh@linutronix.de>
 <9afab1bb-43d6-4f17-b45d-7f4569d9db70@kernel.org>
Date: Wed, 05 Jun 2024 12:37:36 +0200
Message-ID: <871q5bad5b.fsf@toke.dk>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Jesper Dangaard Brouer <hawk@kernel.org> writes:

> On 31/05/2024 12.38, Sebastian Andrzej Siewior wrote:
>> On 2024-05-30 00:09:21 [+0200], Toke H=C3=B8iland-J=C3=B8rgensen wrote:
>>> [...]
>>>> @@ -240,12 +240,14 @@ static int cpu_map_bpf_prog_run(struct bpf_cpu_m=
ap_entry *rcpu, void **frames,
>>>>   				int xdp_n, struct xdp_cpumap_stats *stats,
>>>>   				struct list_head *list)
>>>>   {
>>>> +	struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
>>>>   	int nframes;
>  >>
>>> I think we need to zero-initialise all the context objects we allocate
>>> on the stack.
>>>
>> Okay, I can do that.
>
> Hmm, but how will this affect performance?

My hunch would be that this would be in a cache line we're touching
anyway, so it won't make much difference? But better measure, I suppose :)

-Toke