Messages in this thread Patch in this message | | | From | Waiman Long <> | Subject | [PATCH v2 1/2] cgroup: Add a hint to allow v1 controller to use v2 behavior | Date | Thu, 17 Aug 2017 14:25:38 -0400 |
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For some cgroup controllers, the behavior on cgroup v1 differs somewhat from cgroup v2. To indicate that a controller can use v2 behavior in cgroup v1, a new cgroupfs mount option "v2_mode" is added. This is essentially a hint, there is no obligation for a controller to comply with this semantics.
Signed-off-by: Waiman Long <longman@redhat.com> --- include/linux/cgroup-defs.h | 5 +++++ kernel/cgroup/cgroup-v1.c | 6 ++++++ 2 files changed, 11 insertions(+)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 09f4c7d..fae33ed 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -74,6 +74,11 @@ enum { * aren't writeable from inside the namespace. */ CGRP_ROOT_NS_DELEGATE = (1 << 3), + + /* + * A hint that v1 cgroup should use v2 behavior, if applicable. + */ + CGRP_ROOT_V2_MODE = (1 << 4), }; /* cftype->flags */ diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 7bf4b15..77e22a4 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -846,6 +846,8 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo seq_puts(seq, ",noprefix"); if (root->flags & CGRP_ROOT_XATTR) seq_puts(seq, ",xattr"); + if (root->flags & CGRP_ROOT_V2_MODE) + seq_puts(seq, ",v2_mode"); spin_lock(&release_agent_path_lock); if (strlen(root->release_agent_path)) @@ -900,6 +902,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) opts->cpuset_clone_children = true; continue; } + if (!strcmp(token, "v2_mode")) { + opts->flags |= CGRP_ROOT_V2_MODE; + continue; + } if (!strcmp(token, "xattr")) { opts->flags |= CGRP_ROOT_XATTR; continue; -- 1.8.3.1
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