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authorBen Blum <bblum@andrew.cmu.edu>2011-05-27 03:25:18 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-27 04:12:34 +0400
commit4714d1d32d97239fb5ae3e10521d3f133a899b66 (patch)
treefb50707cefc386bf4e87cac9661a38dcfe3192df /include/linux/init_task.h
parentdcb3a08e69629ea65a3e9647da730bfaf670497d (diff)
downloadlinux-4714d1d32d97239fb5ae3e10521d3f133a899b66.tar.xz
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 <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/init_task.h')
-rw-r--r--include/linux/init_task.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index bafc58c00fc3..580f70c02391 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;