From 3c14f8b44fafaa60519440bea1591e495b928327 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 13 Aug 2013 20:22:51 -0400 Subject: [PATCH] cgroup: move subsys file removal to kill_css() With the planned unified hierarchy, individual css's will be created and destroyed dynamically across the lifetime of a cgroup. To enable such usages, css destruction is being decoupled from cgroup destruction. This patch moves subsys file removal from cgroup_destroy_locked() to kill_css(). While this changes the order of destruction operations, the changes shouldn't be noticeable to cgroup subsystems or userland. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- kernel/cgroup.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 7b7575f..3137e38 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4599,13 +4599,15 @@ static void css_killed_ref_fn(struct percpu_ref *ref) * kill_css - destroy a css * @css: css to destroy * - * This function initiates destruction of @css by putting its base - * reference. ->css_offline() will be invoked asynchronously once - * css_tryget() is guaranteed to fail and when the reference count reaches - * zero, @css will be released. + * This function initiates destruction of @css by removing cgroup interface + * files and putting its base reference. ->css_offline() will be invoked + * asynchronously once css_tryget() is guaranteed to fail and when the + * reference count reaches zero, @css will be released. */ static void kill_css(struct cgroup_subsys_state *css) { + cgroup_clear_dir(css->cgroup, 1 << css->ss->subsys_id); + /* * Killing would put the base ref, but we need to keep it alive * until after ->css_offline(). @@ -4703,10 +4705,10 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) cgroup_destroy_css_killed(cgrp); /* - * Clear and remove @cgrp directory. The removal puts the base ref - * but we aren't quite done with @cgrp yet, so hold onto it. + * Clear the base files and remove @cgrp directory. The removal + * puts the base ref but we aren't quite done with @cgrp yet, so + * hold onto it. */ - cgroup_clear_dir(cgrp, cgrp->root->subsys_mask); cgroup_addrm_files(cgrp, cgroup_base_files, false); dget(d); cgroup_d_remove_dir(d); -- 2.7.4