From: Hao Luo <haoluo@google.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
"open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
KP Singh <kpsingh@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Jiri Olsa <jolsa@kernel.org>, Michal Koutny <mkoutny@suse.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
David Rientjes <rientjes@google.com>,
Stanislav Fomichev <sdf@google.com>,
Shakeel Butt <shakeelb@google.com>,
Yosry Ahmed <yosryahmed@google.com>
Subject: Re: [RESEND PATCH bpf-next v9 0/5] bpf: rstat: cgroup hierarchical
Date: Wed, 24 Aug 2022 17:42:18 -0700 [thread overview]
Message-ID: <CA+khW7gQi+BK7Qy4Khk=Ro72nfNQaR2kNkwZemB9ELnDo4Nk3Q@mail.gmail.com> (raw)
In-Reply-To: <CAADnVQLT3JE8LtOYrs30mL88PNs+NaSeXgQqAPEAup5LUC+BPQ@mail.gmail.com>
On Wed, Aug 24, 2022 at 5:29 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Wed, Aug 24, 2022 at 4:31 PM Hao Luo <haoluo@google.com> wrote:
> >
> > This patch series allows for using bpf to collect hierarchical cgroup
> > stats efficiently by integrating with the rstat framework. The rstat
> > framework provides an efficient way to collect cgroup stats percpu and
> > propagate them through the cgroup hierarchy.
> >
> > The stats are exposed to userspace in textual form by reading files in
> > bpffs, similar to cgroupfs stats by using a cgroup_iter program.
> > cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes:
> > - walking a cgroup's descendants in pre-order.
> > - walking a cgroup's descendants in post-order.
> > - walking a cgroup's ancestors.
> > - process only a single object.
> >
> > When attaching cgroup_iter, one needs to set a cgroup to the iter_link
> > created from attaching. This cgroup can be passed either as a file
> > descriptor or a cgroup id. That cgroup serves as the starting point of
> > the walk.
> >
> > One can also terminate the walk early by returning 1 from the iter
> > program.
> >
> > Note that because walking cgroup hierarchy holds cgroup_mutex, the iter
> > program is called with cgroup_mutex held.
> >
> > ** Background on rstat for stats collection **
> > (I am using a subscriber analogy that is not commonly used)
> >
> > The rstat framework maintains a tree of cgroups that have updates and
> > which cpus have updates. A subscriber to the rstat framework maintains
> > their own stats. The framework is used to tell the subscriber when
> > and what to flush, for the most efficient stats propagation. The
> > workflow is as follows:
> >
> > - When a subscriber updates a cgroup on a cpu, it informs the rstat
> > framework by calling cgroup_rstat_updated(cgrp, cpu).
> >
> > - When a subscriber wants to read some stats for a cgroup, it asks
> > the rstat framework to initiate a stats flush (propagation) by calling
> > cgroup_rstat_flush(cgrp).
> >
> > - When the rstat framework initiates a flush, it makes callbacks to
> > subscribers to aggregate stats on cpus that have updates, and
> > propagate updates to their parent.
> >
> > Currently, the main subscribers to the rstat framework are cgroup
> > subsystems (e.g. memory, block). This patch series allow bpf programs to
> > become subscribers as well.
> >
> > Patches in this series are organized as follows:
> > * Patches 1-2 introduce cgroup_iter prog, and a selftest.
> > * Patches 3-5 allow bpf programs to integrate with rstat by adding the
> > necessary hook points and kfunc. A comprehensive selftest that
> > demonstrates the entire workflow for using bpf and rstat to
> > efficiently collect and output cgroup stats is added.
> >
> > ---
> > Changelog:
> > v8 -> v9:
> > - Make UNSPEC (an invalid option) as the default order for cgroup_iter.
> > - Use enum for specifying cgroup_iter order, instead of u32.
> > - Add BPF_ITER_RESHCED to cgroup_iter.
> > - Add cgroup_hierarchical_stats to s390x denylist.
>
> What 'RESEND' is for?
> It seems to confuse patchwork and BPF CI.
>
> The v9 series made it to patchwork...
>
> Please just bump the version to v10 next time.
> Don't add things to subject, since automation cannot recognize
> that yet.
Sorry about that. I thought it was RESEND because no content has
changed. It was just adding an entry in s390 denylist.
Are we good now? Or I need to send a v10?
next prev parent reply other threads:[~2022-08-25 0:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 23:31 [RESEND PATCH bpf-next v9 0/5] bpf: rstat: cgroup hierarchical Hao Luo
2022-08-24 23:31 ` [RESEND PATCH bpf-next v9 1/5] bpf: Introduce cgroup iter Hao Luo
2022-08-25 23:00 ` Yonghong Song
2022-08-29 18:07 ` Hao Luo
2022-08-24 23:31 ` [RESEND PATCH bpf-next v9 2/5] selftests/bpf: Test cgroup_iter Hao Luo
2022-08-24 23:31 ` [RESEND PATCH bpf-next v9 3/5] cgroup: bpf: enable bpf programs to integrate with rstat Hao Luo
2022-08-24 23:31 ` [RESEND PATCH bpf-next v9 4/5] selftests/bpf: extend cgroup helpers Hao Luo
2022-08-24 23:31 ` [RESEND PATCH bpf-next v9 5/5] selftests/bpf: add a selftest for cgroup hierarchical stats collection Hao Luo
2022-08-25 2:09 ` Alexei Starovoitov
2022-08-25 2:41 ` Yosry Ahmed
2022-08-25 18:43 ` Alexei Starovoitov
2022-08-25 18:45 ` Yosry Ahmed
2022-08-25 18:52 ` Hao Luo
2022-08-25 0:29 ` [RESEND PATCH bpf-next v9 0/5] bpf: rstat: cgroup hierarchical Alexei Starovoitov
2022-08-25 0:42 ` Hao Luo [this message]
2022-08-25 0:47 ` Alexei Starovoitov
2022-08-25 0:48 ` Hao Luo
2022-08-25 18:40 ` patchwork-bot+netdevbpf
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