lkml.org 
[lkml]   [2009]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4/9] support checking of cgroup subsystem dependencies
Date
From: Li Zefan <lizf@cn.fujitsu.com>

From: Li Zefan <lizf@cn.fujitsu.com>

This allows one subsystem to require to be mounted only when some other
subsystems are also present in or not in the proposed hierarchy.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
Documentation/cgroups/cgroups.txt | 5 +++++
include/linux/cgroup.h | 2 ++
kernel/cgroup.c | 19 ++++++++++++++++++-
3 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
index 6eb1a97..6938025 100644
--- a/Documentation/cgroups/cgroups.txt
+++ b/Documentation/cgroups/cgroups.txt
@@ -552,6 +552,11 @@ and root cgroup. Currently this will only involve movement between
the default hierarchy (which never has sub-cgroups) and a hierarchy
that is being created/destroyed (and hence has no sub-cgroups).

+int subsys_depend(struct cgroup_subsys *ss, unsigned long subsys_bits)
+Called when a cgroup subsystem wants to check if some other subsystems
+are also present in the proposed hierarchy. If this method returns error,
+the mount of the cgroup filesystem will fail.
+
4. Questions
============

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 665fa70..37ace23 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -385,6 +385,8 @@ struct cgroup_subsys {
struct cgroup *cgrp);
void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp);
void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
+ int (*subsys_depend)(struct cgroup_subsys *ss,
+ unsigned long subsys_bits);

int subsys_id;
int active;
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 382109b..fad3f08 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -830,6 +830,23 @@ static int cgroup_show_options(struct seq_file *seq, struct vfsmount *vfs)
return 0;
}

+static int check_subsys_dependency(unsigned long subsys_bits)
+{
+ int i;
+ int ret;
+ struct cgroup_subsys *ss;
+
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ ss = subsys[i];
+ if (test_bit(i, &subsys_bits) && ss->subsys_depend) {
+ ret = ss->subsys_depend(ss, subsys_bits);
+ if (ret)
+ return ret;
+ }
+ }
+ return 0;
+}
+
struct cgroup_sb_opts {
unsigned long subsys_bits;
unsigned long flags;
@@ -890,7 +907,7 @@ static int parse_cgroupfs_options(char *data,
if (!opts->subsys_bits)
return -EINVAL;

- return 0;
+ return check_subsys_dependency(opts->subsys_bits);
}

static int cgroup_remount(struct super_block *sb, int *flags, char *data)
--
1.5.6.3


\
 
 \ /
  Last update: 2009-04-14 22:25    [W:0.159 / U:55.772 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site