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authorTejun Heo <tj@kernel.org>2014-11-18 02:49:51 -0500
committerTejun Heo <tj@kernel.org>2014-11-18 02:49:51 -0500
commit56c807ba4e91f0980567b6a69de239677879b17f (patch)
tree509bdb009fdd4cbc87c75b2138e07600afc357ac
parent7d172cc89b8589e4173d0c73a1ddaae408f29c9d (diff)
downloadop-kernel-dev-56c807ba4e91f0980567b6a69de239677879b17f.zip
op-kernel-dev-56c807ba4e91f0980567b6a69de239677879b17f.tar.gz
cgroup: add cgroup_subsys->css_e_css_changed()
Add a new cgroup_subsys operatoin ->css_e_css_changed(). This is invoked if any of the effective csses seen from the css's cgroup may have changed. This will be used to implement cgroup writeback support. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Zefan Li <lizefan@huawei.com>
-rw-r--r--include/linux/cgroup.h1
-rw-r--r--kernel/cgroup.c18
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index e717a39..3a04aeb 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -615,6 +615,7 @@ struct cgroup_subsys {
void (*css_released)(struct cgroup_subsys_state *css);
void (*css_free)(struct cgroup_subsys_state *css);
void (*css_reset)(struct cgroup_subsys_state *css);
+ void (*css_e_css_changed)(struct cgroup_subsys_state *css);
int (*can_attach)(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c855869..69f0335 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2836,6 +2836,24 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
}
}
+ /*
+ * The effective csses of all the descendants (excluding @cgrp) may
+ * have changed. Subsystems can optionally subscribe to this event
+ * by implementing ->css_e_css_changed() which is invoked if any of
+ * the effective csses seen from the css's cgroup may have changed.
+ */
+ for_each_subsys(ss, ssid) {
+ struct cgroup_subsys_state *this_css = cgroup_css(cgrp, ss);
+ struct cgroup_subsys_state *css;
+
+ if (!ss->css_e_css_changed || !this_css)
+ continue;
+
+ css_for_each_descendant_pre(css, this_css)
+ if (css != this_css)
+ ss->css_e_css_changed(css);
+ }
+
kernfs_activate(cgrp->kn);
ret = 0;
out_unlock:
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