summaryrefslogtreecommitdiff
path: root/include/linux/cgroup-defs.h
diff options
context:
space:
mode:
authorTejun Heo <tj@kernel.org>2015-05-13 23:35:16 +0300
committerTejun Heo <tj@kernel.org>2015-05-27 03:35:00 +0300
commit7d7efec368d537226142cbe559f45797f18672f9 (patch)
tree8b391dada2b97b66f9fbd4315b397516f13199de /include/linux/cgroup-defs.h
parent8ab456ac3697dbd1d3eae5d5817dba941faf89ee (diff)
downloadlinux-7d7efec368d537226142cbe559f45797f18672f9.tar.xz
sched, cgroup: reorganize threadgroup locking
threadgroup_change_begin/end() are used to mark the beginning and end of threadgroup modifying operations to allow code paths which require a threadgroup to stay stable across blocking operations to synchronize against those sections using threadgroup_lock/unlock(). It's currently implemented as a general mechanism in sched.h using per-signal_struct rwsem; however, this never grew non-cgroup use cases and becomes noop if !CONFIG_CGROUPS. It turns out that cgroups is gonna be better served with a different sycnrhonization scheme and is a bit silly to keep cgroups specific details as a general mechanism. What's general here is identifying the places where threadgroups are modified. This patch restructures threadgroup locking so that threadgroup_change_begin/end() become a place where subsystems which need to sycnhronize against threadgroup changes can hook into. cgroup_threadgroup_change_begin/end() which operate on the per-signal_struct rwsem are created and threadgroup_lock/unlock() are moved to cgroup.c and made static. This is pure reorganization which doesn't cause any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
Diffstat (limited to 'include/linux/cgroup-defs.h')
-rw-r--r--include/linux/cgroup-defs.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 55f3120fb952..1b8c93806dbd 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -14,6 +14,7 @@
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/percpu-refcount.h>
+#include <linux/percpu-rwsem.h>
#include <linux/workqueue.h>
#ifdef CONFIG_CGROUPS
@@ -460,5 +461,14 @@ struct cgroup_subsys {
unsigned int depends_on;
};
+void cgroup_threadgroup_change_begin(struct task_struct *tsk);
+void cgroup_threadgroup_change_end(struct task_struct *tsk);
+
+#else /* CONFIG_CGROUPS */
+
+static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) {}
+static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {}
+
#endif /* CONFIG_CGROUPS */
+
#endif /* _LINUX_CGROUP_DEFS_H */