Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 5 Aug 2010 13:26:21 -0700 | Subject | Re: [PATCH 2/2] CRED: Fix __task_cred()'s lockdep check and banner comment |
| |
On Thu, Aug 5, 2010 at 1:13 PM, Eric W. Biederman <ebiederm@xmission.com> wrote: > > I think it is totally reasonable to add a per pid lock, > that would protect the pid->task[...] hlist. That would make > things clearer and finer grained without a lot of effort. Just > a little more struct pid bloat, and a little extra care in fork, > when we add to those lists.
Hmm. Have you taken a look at Nick Piggin's VFS scalability patches? They introduce this "RCU-safe hash chain lock", where each hashchain has a lock-bit in the low bit. I wonder if that would be the right thing to use?
> Even with the per-pgrp lock we still need a lock on the global process > list for the kill -KILL -1 case. Which suggests that tasklist_lock is > still needed for part of kill_something_info.
Well, that -1 case is special anyway. The fact that we might want to use the tasklist_lock there is not very relevant, I think. That is _not_ a hotpath, really (at least not under any relevant loads, I'm sure you could make a silly benchmark of "kill(-1,0)").
Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |