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Mon, 13 Jul 2026 19:56:24 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Dhaval Giani Date: Mon, 13 Jul 2026 19:56:13 -0700 X-Gm-Features: AVVi8CcQ___wGeOqrsOfgmyNGziqF2dEe-CIPz-cn_kIvJqsOiZJbdSnUo6ww30 Message-ID: Subject: Re: Implementing a control group manager that isn't a persistent daemon To: Demi Marie Obenour , Tom James Hromatka , Kamalesh Babulal Content-Type: multipart/alternative; boundary="000000000000409c040656895a9f" X-MailFrom: dhaval.giani@gmail.com X-Mailman-Rule-Hits: header-match-devel.spectrum-os.org-2 X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; header-match-devel.spectrum-os.org-0; header-match-devel.spectrum-os.org-1 Message-ID-Hash: TDN6UEZE2RMYRWN54YBB2PNJXYUFSWV4 X-Message-ID-Hash: TDN6UEZE2RMYRWN54YBB2PNJXYUFSWV4 X-Mailman-Approved-At: Wed, 15 Jul 2026 09:57:56 +0000 CC: Linux cgroups development , Alyssa Ross , Spectrum OS Development X-Mailman-Version: 3.3.10 Precedence: list List-Id: Patches and low-level development discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --000000000000409c040656895a9f Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sun, Jul 12, 2026 at 3:51=E2=80=AFPM Demi Marie Obenour wrote: > Hello! > > I'm currently implementing a control group manager that isn't a > persistent daemon. Instead, it's a command-line tool. The system > I'm working on uses s6 instead of systemd, and s6 doesn't have native > control group support. > > The current plan is to offer a few options: > > 1. Create a cgroup if it doesn't exist. If it does, wait for it to > be empty. Then execute a program in that cgroup. > > 2. Create a program in a cgroup, without waiting for the cgroup to > be empty. > > 2. Kill all programs in a cgroup. > > Why can libcgroup not do the same for you? Dhaval > Unfortunately, I'm not able to wait for a cgroup to become empty. > I don't seem to be getting EPOLLPRI or EPOLLERR events. What > is the proper way to get those events? Is there a kernel version > with a bug in this area? > -- > Sincerely, > Demi Marie Obenour (she/her/hers) > > > --000000000000409c040656895a9f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Sun, Jul 12,= 2026 at 3:51=E2=80=AFPM Demi Marie Obenour <demiobenour@gmail.com> wrote:
Hello!

I'm currently implementing a control group manager that isn't a
persistent daemon.=C2=A0 Instead, it's a command-line tool.=C2=A0 The s= ystem
I'm working on uses s6 instead of systemd, and s6 doesn't have nati= ve
control group support.

The current plan is to offer a few options:

1. Create a cgroup if it doesn't exist.=C2=A0 If it does, wait for it t= o
=C2=A0 =C2=A0be empty.=C2=A0 Then execute a program in that cgroup.

2. Create a program in a cgroup, without waiting for the cgroup to
=C2=A0 =C2=A0be empty.

2. Kill all programs in a cgroup.


Why can libcgroup not do the same for = you?

Dhaval
=C2=A0
Unfortunately, I'm not able to wait for a cgroup to become empty.
I don't seem to be getting EPOLLPRI or EPOLLERR events.=C2=A0 What
is the proper way to get those events?=C2=A0 Is there a kernel version
with a bug in this area?
--
Sincerely,
Demi Marie Obenour (she/her/hers)


--000000000000409c040656895a9f--