Re: [PATCH -mm 3/3] proc: make task_sig() lockless

From: Oleg Nesterov
Date: Tue Apr 13 2010 - 16:03:19 EST


OK. Andrew, please drop

proc-make-collect_sigign_sigcatch-rcu-safe.patch
proc-make-task_sig-lockless.patch

On 04/12, Roland McGrath wrote:
>
> > Yes, /proc/pid/status can report the intermediate state, I even sent
> > the updated changelog to document this.
> >
> > But if you are not sure this is OK, I am worried. Do you think we should
> > drop this patch? If yes, I won't argue.
>
> I'm not dead-set against it, but I am hesitant. My inclination is not to
> remove any previous userland atomicity guarantees with regard to observable
> signal state in any form.

OK. Not that I really understand why do we need atomicity, but OK.

I was going to remove ->siglock from /fs/proc/ completely (except
do_io_accounting), but given that nobody replied to do_task_stat patches
this will not happen soon.

> At least, don't do that in part of a whole
> cleanup flurry where it is intermixed with lots of changes that really are
> pure cleanup with absolutely no userland-observable change.

OK. Anyway, these changes are simple, we can reconsider them later.

Oleg.

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