Changes css_set freeing mechanism to be under RCU This is a prepatch for making the procs file writable. In order to free the old css_sets for each task to be moved as they're being moved, the freeing mechanism must be RCU-protected, or else we would have to have a call to synchronize_rcu() for each task before freeing its old css_set. Signed-off-by: Ben Blum <bblum@xxxxxxxxxx> --- include/linux/cgroup.h | 3 +++ kernel/cgroup.c | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b934b72..24e3f1a 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -260,6 +260,9 @@ struct css_set { * during subsystem registration (at boot time). */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; + + /* For RCU-protected deletion */ + struct rcu_head rcu_head; }; /* diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 7e6b183..637a54e 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -288,6 +288,12 @@ static void unlink_css_set(struct css_set *cg) } } +static void free_css_set_rcu(struct rcu_head *obj) +{ + struct css_set *cg = container_of(obj, struct css_set, rcu_head); + kfree(cg); +} + static void __put_css_set(struct css_set *cg, int taskexit) { int i; @@ -317,7 +323,7 @@ static void __put_css_set(struct css_set *cg, int taskexit) } } rcu_read_unlock(); - kfree(cg); + call_rcu(&cg->rcu_head, free_css_set_rcu); } /* _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers