From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: [PATCH 1/2] cgroup: make serial_nr_cursor available throughout cgroup.c Date: Tue, 18 Jun 2013 18:48:18 +0800 Message-ID: <51C03AF2.7050702@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo , LKML , cgroups The next patch will use it to determine if a cgroup is newly created while we're iterating the cgroup hierarchy. Signed-off-by: Li Zefan --- These two patches are based on the fixes I just sent. --- kernel/cgroup.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e8a40e3..b1d98f2 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -198,6 +198,15 @@ static DEFINE_IDR(cgroup_hierarchy_idr); static struct cgroup_name root_cgroup_name = { .name = "/" }; +/* + * Assign a monotonically increasing serial number. It guarantees + * cgroups with bigger numbers are newer than those with smaller + * numbers. Also with the list appending, it guarantees that sibling + * cgroups are always sorted in the ascending serial number order on + * the parent's ->children. + */ +static atomic64_t cgroup_serial_nr_cursor = ATOMIC64_INIT(0); + /* This flag indicates whether tasks in the fork and exit paths should * check for fork/exit handlers to call. This avoids us having to do * extra work in the fork/exit path if none of the subsystems need to @@ -4212,7 +4221,6 @@ static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp) static long cgroup_create(struct cgroup *parent, struct dentry *dentry, umode_t mode) { - static atomic64_t serial_nr_cursor = ATOMIC64_INIT(0); struct cgroup *cgrp; struct cgroup_name *name; struct cgroupfs_root *root = parent->root; @@ -4305,7 +4313,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, * sorted in the ascending serial number order on the parent's * ->children. */ - cgrp->serial_nr = atomic64_inc_return(&serial_nr_cursor); + cgrp->serial_nr = atomic64_inc_return(&cgroup_serial_nr_cursor); /* allocation complete, commit to creation */ list_add_tail(&cgrp->allcg_node, &root->allcg_list); -- 1.8.0.2