From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Gushchin Subject: Re: [PATCH 2/5] docs/cgroup: add entry for cgroup.kill Date: Thu, 29 Apr 2021 20:22:03 -0700 Message-ID: References: <20210429120113.2238065-1-brauner@kernel.org> <20210429120113.2238065-2-brauner@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=date : from : to : cc : subject : message-id : references : content-type : in-reply-to : mime-version; s=facebook; bh=QM3TwYOmgGt8gt7A54p7wXFWNh2YZdFv2N9SQ0DZZlY=; b=OTaDRaQkhkvuD1/3zGSq1g5WfTs3cMAaQaGwFhQnoJjmLJafrEyPg2ySc77GoqnbdIOh JWZg10vOr6JW+teKUy1aew5Iw5UbWIefABk6dARkDVfPGR/yz+VCKi23IwzZxPt9jyLX Et1eTHCPXc6Bq5u80m/FlyS57v6A1d/3nrw= Content-Disposition: inline In-Reply-To: <20210429120113.2238065-2-brauner-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-ID: Content-Transfer-Encoding: 7bit To: Christian Brauner Cc: Tejun Heo , Shakeel Butt , Zefan Li , Johannes Weiner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Christian Brauner On Thu, Apr 29, 2021 at 02:01:10PM +0200, Christian Brauner wrote: > From: Christian Brauner > > Give a brief overview of the cgroup.kill functionality. > > Cc: Roman Gushchin > Cc: Tejun Heo > Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > Signed-off-by: Christian Brauner > --- > Documentation/admin-guide/cgroup-v2.rst | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index 64c62b979f2f..c9f656a84590 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -949,6 +949,23 @@ All cgroup core files are prefixed with "cgroup." > it's possible to delete a frozen (and empty) cgroup, as well as > create new sub-cgroups. > > + cgroup.kill > + A write-only single value file which exists in non-root cgroups. > + The only allowed value is "1". > + > + Writing "1" to the file causes the cgroup and all descendant cgroups to > + be killed. This means that all processes located in the affected cgroup > + tree will be killed via SIGKILL. > + > + Killing a cgroup tree will deal with concurrent forks appropriately and > + is protected against migrations. If callers require strict guarantees > + they can issue the cgroup.kill request after a freezing the cgroup via > + cgroup.freeze. Hm, is it necessarily? What additional guarantees adds using the freezer? > + > + In a threaded cgroup, writing this file fails with EOPNOTSUPP as > + killing cgroups is a process directed operation, i.e. it affects > + the whole thread-group. > + > Controllers > =========== > > -- > 2.27.0 >