Hello, Oleg. On Wed, Mar 06, 2013 at 07:16:08PM +0100, Oleg Nesterov wrote: > And how SIGFREEZE can help? If we want to interrupt the sleeps in NFS/RPC > layer we can simply add TASK_WAKEFREEZE (can be used with TASK_KILLABLE) > and change freeze_task() to do signal_wake_up_state(TASK_WAKEFREEZE). Oh yeah, we don't need another signal. We just need sigpending state and a wakeup. I wasn't really going into details. The important point is that for code paths outside signal/ptrace, freezing could look and behave about the same as signal delivery. > But if we can do this, then it should be possible so simply make these > sleeps TASK_INTERRUPTIBLE ? But it seems that we can't just because we > can't always restart, so I am totally confused. Of course, switching to another freezing mechanism doesn't make issues like this go away in itself, but it would at least allow handling such issues in easier to grasp way rather than dealing with this giant pseudo lock and allows code paths outside jobctl to simply deal with one issue - signal delivery, rather than having to deal with freezing separately. Also, while not completely identical, frozen state would at least be an extension of jobctl trap and it would be possible to allow things like killing frozen tasks or even ptracing them in well-defined manner for cgroup_freezer use cases. As it currently stands, there is no well-defined abstraction for frozen state which we can expose in any way, which sucks. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
