Messages in this thread Patch in this message | | | Date | Wed, 10 Jan 2018 04:44:14 -0800 | From | Roman Gushchin <> | Subject | Re: cgroups(7): documenting /sys/kernel/cgroup files |
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Hello Michael,
On Wed, Jan 10, 2018 at 05:23:32AM +0100, Michael Kerrisk (man-pages) wrote: > Hello Roman, > > On 8 January 2018 at 22:11, Michael Kerrisk (man-pages) > <mtk.manpages@gmail.com> wrote: > > Hello Roman, > > > > I wrote cgroups(7) text below to document the files added by you in > > Linux 4.15. Could you let me know if the following text is okay please: > > > > /sys/kernel/cgroup files > > /sys/kernel/cgroup/delegate (since Linux 4.15) > > This file exports a list of the cgroups v2 files (one per > > line) that are delegatable (i.e., whose ownership should be > > changed to the user ID of the delegatee). In the future, > > the set of delegatable files may change or grow, and this > > file provides a way for the kernel to inform user-space > > applications of which files must be delegated. As at Linux > > 4.15, one sees the following when inspecting this file: > > > > $ cat /sys/kernel/cgroup/delegate > > cgroup.procs > > cgroup.subtree_control > > I have a question about /sys/kernel/cgroup/delegate: why does this > file not list cgroup.threads, since that is also a file that > (potentially) should be delegated?
cc Tejun
cgroup.threads is not listed because it's not delegatable (doesn't have CFTYPE_NS_DELEGATABLE flag set). I don't know if it was intended or just an accident (I believe the latter).
Thanks!
PS In the latter case the following patch should fix it:
From fdf19edb6e9594e48e89d4510767b9eb6ca2d9dd Mon Sep 17 00:00:00 2001 From: Roman Gushchin <guro@fb.com> Date: Wed, 10 Jan 2018 04:35:12 -0800 Subject: [PATCH] cgroup: make cgroup.threads delegatable
Make cgroup.threads file delegatable. The behavior of cgroup.threads should follow the behavior of cgroup.procs.
Signed-off-by: Roman Gushchin <guro@fb.com> Discovered-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Tejun Heo <tj@kernel.org> --- kernel/cgroup/cgroup.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 0b1ffe147f24..b74d9ee1425c 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4449,6 +4449,7 @@ static struct cftype cgroup_base_files[] = { }, { .name = "cgroup.threads", + .flags = CFTYPE_NS_DELEGATABLE, .release = cgroup_procs_release, .seq_start = cgroup_threads_start, .seq_next = cgroup_procs_next, -- 2.14.3
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