From 4714d1d32d97239fb5ae3e10521d3f133a899b66 Mon Sep 17 00:00:00 2001 From: Ben Blum Date: Thu, 26 May 2011 16:25:18 -0700 Subject: cgroups: read-write lock CLONE_THREAD forking per threadgroup Adds functionality to read/write lock CLONE_THREAD fork()ing per-threadgroup Add an rwsem that lives in a threadgroup's signal_struct that's taken for reading in the fork path, under CONFIG_CGROUPS. If another part of the kernel later wants to use such a locking mechanism, the CONFIG_CGROUPS ifdefs should be changed to a higher-up flag that CGROUPS and the other system would both depend on. This is a pre-patch for cgroup-procs-write.patch. Signed-off-by: Ben Blum Cc: "Eric W. Biederman" Cc: Li Zefan Cc: Matt Helsley Reviewed-by: Paul Menage Cc: Oleg Nesterov Cc: David Rientjes Cc: Miao Xie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/init_task.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/init_task.h') diff --git a/include/linux/init_task.h b/include/linux/init_task.h index bafc58c00fc..580f70c0239 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -22,6 +22,14 @@ extern struct files_struct init_files; extern struct fs_struct init_fs; +#ifdef CONFIG_CGROUPS +#define INIT_THREADGROUP_FORK_LOCK(sig) \ + .threadgroup_fork_lock = \ + __RWSEM_INITIALIZER(sig.threadgroup_fork_lock), +#else +#define INIT_THREADGROUP_FORK_LOCK(sig) +#endif + #define INIT_SIGNALS(sig) { \ .nr_threads = 1, \ .wait_chldexit = __WAIT_QUEUE_HEAD_INITIALIZER(sig.wait_chldexit),\ @@ -38,6 +46,7 @@ extern struct fs_struct init_fs; }, \ .cred_guard_mutex = \ __MUTEX_INITIALIZER(sig.cred_guard_mutex), \ + INIT_THREADGROUP_FORK_LOCK(sig) \ } extern struct nsproxy init_nsproxy; -- cgit v1.2.3-70-g09d2