Paul Menage wrote: > From: Ben Blum <[email protected]> > > > Adds functionality to read/write lock CLONE_THREAD fork()ing per-threadgroup > > This patch adds an rwsem that lives in a threadgroup's sighand_struct (next to > the sighand's atomic count, to piggyback on its cacheline), and two functions > in kernel/cgroup.c (for now) for easily+safely obtaining and releasing it. 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, and the lock/unlock functions could be > moved to sched.c or so. > > Signed-off-by: Ben Blum <[email protected]> > Signed-off-by: Paul Menage <[email protected]> >
Looks fine to me. Acked-by: Li Zefan <[email protected]> ... > +struct sighand_struct *threadgroup_fork_lock(struct task_struct *tsk) > +{ > + struct sighand_struct *sighand; > + struct task_struct *p; > + > + /* tasklist lock protects sighand_struct's disappearance in exit(). */ > + read_lock(&tasklist_lock); > + if (likely(tsk->sighand)) { > + /* simple case - check the thread we were given first */ > + sighand = tsk->sighand; > + } else { > + sighand = NULL; > + /* > + * tsk is exiting; try to find another thread in the group > + * whose sighand pointer is still alive. > + */ > + rcu_read_lock(); since we are holding tasklist_lock, I think we don't need to take rcu lock? > + list_for_each_entry_rcu(p, &tsk->thread_group, thread_group) { > + if (p->sighand) { > + sighand = tsk->sighand; s/tsk->sighand/p->sighand > + break; > + } > + } > + rcu_read_unlock(); > + } _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
