From: Stanislav Fomichev <sdf@google.com>
To: Jose Fernandez <josef@netflix.com>
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>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org,
Tycho Andersen <tycho@tycho.pizza>
Subject: Re: [PATCH V2 bpf-next 1/2] bpf: add bpf_task_get_cgroup kfunc
Date: Mon, 18 Mar 2024 09:07:13 -0700 [thread overview]
Message-ID: <ZfhmsVTIe-khu9uP@google.com> (raw)
In-Reply-To: <20240316162241.628855-1-josef@netflix.com>
On 03/16, Jose Fernandez wrote:
> This patch enhances the BPF helpers by adding a kfunc to retrieve the
> cgroup v2 of a task, addressing a previous limitation where only
> bpf_task_get_cgroup1 was available for cgroup v1. The new kfunc is
> particularly useful for scenarios where obtaining the cgroup ID of a
> task other than the "current" one is necessary, which the existing
> bpf_get_current_cgroup_id helper cannot accommodate. A specific use
> case at Netflix involved the sched_switch tracepoint, where we had to
> get the cgroup IDs of both the prev and next tasks.
>
> The bpf_task_get_cgroup kfunc acquires and returns a reference to a
> task's default cgroup, ensuring thread-safe access by correctly
> implementing RCU read locking and unlocking. It leverages the existing
> cgroup.h helper, and cgroup_tryget to safely acquire a reference to it.
>
> Signed-off-by: Jose Fernandez <josef@netflix.com>
> Reviewed-by: Tycho Andersen <tycho@tycho.pizza>
Acked-by: Stanislav Fomichev <sdf@google.com>
prev parent reply other threads:[~2024-03-18 16:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-16 16:22 [PATCH V2 bpf-next 1/2] bpf: add bpf_task_get_cgroup kfunc Jose Fernandez
2024-03-16 16:22 ` [PATCH V2 bpf-next 2/2] selftests/bpf: add selftest for bpf_task_get_cgroup Jose Fernandez
2024-03-18 3:10 ` Ratheesh Kannoth
2024-03-18 3:15 ` Alexei Starovoitov
2024-03-18 9:58 ` Jiri Olsa
2024-03-19 0:30 ` Jose Fernandez
2024-03-18 15:54 ` [PATCH V2 bpf-next 1/2] bpf: add bpf_task_get_cgroup kfunc Yonghong Song
2024-03-18 16:07 ` Stanislav Fomichev [this message]
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