lkml.org 
[lkml]   [2011]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 10/11] ptrace: move JOBCTL_TRAPPING wait to wait(2) and ptrace_check_attach()
Hey,

On Thu, May 12, 2011 at 05:59:10PM +0200, Oleg Nesterov wrote:
> > I don't know. Why is retrying hairy? The whole waiting logic is
> > built for clean retries. The suggested change just does it without
> > intervening sleeping and waking up. I don't see anything particularly
> > hairy there.
>
> As always, this is subjective. But I didn't mean -EAGAIN itself. In fact
> I was going to add this (simple) logic some time ago and kill the EXIT_DEAD
> state. Hmm, and I'd still like to do this...

Oh, I've been updating code and it's now using interruptible sleep +
-ERESTARTNOINTR return. It's simpler and the freezer problem is gone
too.

> I meant the whole ptrace_wait_trapping() + lock dance + retry thing.
> But of course I do not pretend my feeling is right.

Yeah, it's more complex than I would have liked. The problem is that
ptrace(2) isn't really equipped with facilities to handle async
events, so it's a bit painful to add async mechanism into the existing
mechanics, but most problems seem solvable.

> Also. _Perhaps_ we can rethink the SIGCONT trapping, and perhaps in
> this case do_wait() won't need any changes. May be.

But, if there's a better way, sure.

Thanks.

--
tejun


\
 
 \ /
  Last update: 2011-05-12 18:09    [W:0.182 / U:0.228 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site