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Message-ID: <20121114155016.GA21657@sergelap>
Date: Wed, 14 Nov 2012 09:50:16 -0600
From: Serge Hallyn <serge.hallyn@...onical.com>
To: Tejun Heo <tj@...nel.org>
Cc: Li Zefan <lizefan@...wei.com>, cgroups@...r.kernel.org,
containers@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] cgroup:
s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/
Quoting Tejun Heo (tj@...nel.org):
> From 6e405c1ae4018d813e8ed9e0bd463d6976aebfa8 Mon Sep 17 00:00:00 2001
> From: Tejun Heo <tj@...nel.org>
> Date: Tue, 13 Nov 2012 12:21:50 -0800
>
> clone_children is only meaningful for cpuset and will stay that way.
> Rename the flag to reflect that and update documentation. Also, drop
> clone_children() wrapper in cgroup.c. The thin wrapper is used only a
> few times and one of them will go away soon.
>
> Signed-off-by: Tejun Heo <tj@...nel.org>
Thanks.
(both)
Acked-by: Serge E. Hallyn <serge.hallyn@...ntu.com>
> Cc: Glauber Costa <glommer@...allels.com>
> ---
> These two patches are based on top of "cgroup: allow->post_create() to
> fail" patchset.
>
> http://thread.gmane.org/gmane.linux.kernel.cgroups/5047
> git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-online-may-fail
>
> and availalbe in the following branch.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-remove-post_clone
>
> Thanks.
>
> Documentation/cgroups/cgroups.txt | 8 +++-----
> include/linux/cgroup.h | 6 ++++--
> kernel/cgroup.c | 28 ++++++++++++----------------
> 3 files changed, 19 insertions(+), 23 deletions(-)
>
> diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
> index b06eea2..24cdf76 100644
> --- a/Documentation/cgroups/cgroups.txt
> +++ b/Documentation/cgroups/cgroups.txt
> @@ -299,11 +299,9 @@ a cgroup hierarchy's release_agent path is empty.
> 1.5 What does clone_children do ?
> ---------------------------------
>
> -If the clone_children flag is enabled (1) in a cgroup, then all
> -cgroups created beneath will call the post_clone callbacks for each
> -subsystem of the newly created cgroup. Usually when this callback is
> -implemented for a subsystem, it copies the values of the parent
> -subsystem, this is the case for the cpuset.
> +This flag only affects the cpuset controller. If the clone_children
> +flag is enabled (1) in a cgroup, a new cpuset cgroup will copy its
> +configuration from the parent during initialization.
>
> 1.6 How do I use cgroups ?
> --------------------------
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 89c631d..926d8d1 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -143,9 +143,11 @@ enum {
> /* Control Group requires release notifications to userspace */
> CGRP_NOTIFY_ON_RELEASE,
> /*
> - * Clone cgroup values when creating a new child cgroup
> + * Clone the parent's configuration when creating a new child
> + * cpuset cgroup. For historical reasons, this option can be
> + * specified at mount time and thus is implemented here.
> */
> - CGRP_CLONE_CHILDREN,
> + CGRP_CPUSET_CLONE_CHILDREN,
> };
>
> struct cgroup {
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 46c5119..a49572e 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -296,11 +296,6 @@ static int notify_on_release(const struct cgroup *cgrp)
> return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
> }
>
> -static int clone_children(const struct cgroup *cgrp)
> -{
> - return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> -}
> -
> /*
> * for_each_subsys() allows you to iterate on each subsystem attached to
> * an active hierarchy
> @@ -1101,7 +1096,7 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
> seq_puts(seq, ",xattr");
> if (strlen(root->release_agent_path))
> seq_printf(seq, ",release_agent=%s", root->release_agent_path);
> - if (clone_children(&root->top_cgroup))
> + if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags))
> seq_puts(seq, ",clone_children");
> if (strlen(root->name))
> seq_printf(seq, ",name=%s", root->name);
> @@ -1113,7 +1108,7 @@ struct cgroup_sb_opts {
> unsigned long subsys_mask;
> unsigned long flags;
> char *release_agent;
> - bool clone_children;
> + bool cpuset_clone_children;
> char *name;
> /* User explicitly requested empty subsystem */
> bool none;
> @@ -1164,7 +1159,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
> continue;
> }
> if (!strcmp(token, "clone_children")) {
> - opts->clone_children = true;
> + opts->cpuset_clone_children = true;
> continue;
> }
> if (!strcmp(token, "xattr")) {
> @@ -1474,8 +1469,8 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
> strcpy(root->release_agent_path, opts->release_agent);
> if (opts->name)
> strcpy(root->name, opts->name);
> - if (opts->clone_children)
> - set_bit(CGRP_CLONE_CHILDREN, &root->top_cgroup.flags);
> + if (opts->cpuset_clone_children)
> + set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags);
> return root;
> }
>
> @@ -3905,7 +3900,7 @@ fail:
> static u64 cgroup_clone_children_read(struct cgroup *cgrp,
> struct cftype *cft)
> {
> - return clone_children(cgrp);
> + return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
> }
>
> static int cgroup_clone_children_write(struct cgroup *cgrp,
> @@ -3913,9 +3908,9 @@ static int cgroup_clone_children_write(struct cgroup *cgrp,
> u64 val)
> {
> if (val)
> - set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> + set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
> else
> - clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> + clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
> return 0;
> }
>
> @@ -4130,8 +4125,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
> if (notify_on_release(parent))
> set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
>
> - if (clone_children(parent))
> - set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
> + if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
> + set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
>
> for_each_subsys(root, ss) {
> struct cgroup_subsys_state *css;
> @@ -4148,7 +4143,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
> goto err_free_all;
> }
> /* At error, ->css_free() callback has to free assigned ID. */
> - if (clone_children(parent) && ss->post_clone)
> + if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags) &&
> + ss->post_clone)
> ss->post_clone(cgrp);
>
> if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
> --
> 1.7.11.7
>
> _______________________________________________
> Containers mailing list
> Containers@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/containers
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