Re: [PATCH 1/2][UPDATED] cgroup: make serial_nr_cursor available throughout cgroup.c
From: Tejun Heo <hidden>
Date: 2013-06-18 18:16:25
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lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From 794611a1dfcb055d7d41ce133378dd8197d73e38 Mon Sep 17 00:00:00 2001 From: Li Zefan <redacted> Date: Tue, 18 Jun 2013 18:53:53 +0800 The next patch will use it to determine if a cgroup is newly created while we're iterating the cgroup hierarchy. tj: Rephrased the comment on top of cgroup_serial_nr_cursor. Signed-off-by: Li Zefan <redacted> Signed-off-by: Tejun Heo <redacted> --- Applied to cgroup/for-3.11 with minor update. Thanks. kernel/cgroup.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1d4f471..e6571ca 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 to cgroups. It + * guarantees cgroups with bigger numbers are newer than those with smaller + * numbers. Also, as cgroups are always appended to the parent's + * ->children list, it guarantees that sibling cgroups are always sorted in + * the ascending serial number order on the list. + */ +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
@@ -4222,7 +4231,6 @@ 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;
@@ -4309,13 +4317,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, goto err_free_all; lockdep_assert_held(&dentry->d_inode->i_mutex); - /* - * Assign a monotonically increasing serial number. With the list - * appending below, it guarantees that sibling cgroups are always - * 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);
--
1.8.2.1