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authorTejun Heo <tj@kernel.org>2016-03-03 09:57:58 -0500
committerTejun Heo <tj@kernel.org>2016-03-03 09:57:58 -0500
commit88cb04b96a1934ecbfd1d324e7cde55890c1a576 (patch)
tree7dc80e8c3054d07ed8a7cc54c738eeae50a69513 /kernel/cgroup.c
parent6cd0f5bbaf594f40a97d01dbc565dda41f30d37c (diff)
downloadlinux-sh-88cb04b96a1934ecbfd1d324e7cde55890c1a576.tar.gz
cgroup: explicitly track whether a cgroup_subsys_state is visible to userland
Currently, whether a css (cgroup_subsys_state) has its interface files created is not tracked and assumed to change together with the owning cgroup's lifecycle. cgroup directory and interface creation is being separated out from internal object creation to help refactoring and eventually allow cgroups which are not visible through cgroupfs. This patch adds CSS_VISIBLE to track whether a css has its interface files created and perform management operations only when necessary which helps decoupling interface file handling from internal object lifecycle. After this patch, all css interface file management functions can be called regardless of the current state and will achieve the expected result. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4178e45becb4..a9a53ca942f3 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1421,6 +1421,11 @@ static void css_clear_dir(struct cgroup_subsys_state *css,
struct cgroup *cgrp = cgrp_override ?: css->cgroup;
struct cftype *cfts;
+ if (!(css->flags & CSS_VISIBLE))
+ return;
+
+ css->flags &= ~CSS_VISIBLE;
+
list_for_each_entry(cfts, &css->ss->cfts, node)
cgroup_addrm_files(css, cgrp, cfts, false);
}
@@ -1439,6 +1444,9 @@ static int css_populate_dir(struct cgroup_subsys_state *css,
struct cftype *cfts, *failed_cfts;
int ret;
+ if (css->flags & CSS_VISIBLE)
+ return 0;
+
if (!css->ss) {
if (cgroup_on_dfl(cgrp))
cfts = cgroup_dfl_base_files;
@@ -1455,6 +1463,9 @@ static int css_populate_dir(struct cgroup_subsys_state *css,
goto err;
}
}
+
+ css->flags |= CSS_VISIBLE;
+
return 0;
err:
list_for_each_entry(cfts, &css->ss->cfts, node) {
@@ -3403,7 +3414,7 @@ static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
struct cgroup *cgrp = css->cgroup;
- if (cgroup_is_dead(cgrp))
+ if (!(css->flags & CSS_VISIBLE))
continue;
ret = cgroup_addrm_files(css, cgrp, cfts, is_add);