Re: ipc,sem: sysv semaphore scalability

From: Davidlohr Bueso
Date: Fri Mar 29 2013 - 22:08:44 EST


On Sat, 2013-03-30 at 08:36 +0700, Emmanuel Benisty wrote:
> Hi Linus,
>
> On Sat, Mar 30, 2013 at 6:16 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > Emmanuel, can you try the attached patch? I think it applies cleanly
> > on top of the scalability series too without any changes, but I didn't
> > check if the patches perhaps changed some of the naming or something.
>
> I had to slightly modify the patch since it wouldn't match the changes
> introduced by 7-7-ipc-sem-fine-grained-locking-for-semtimedop.patch,
> hope that was the right thing to do. So, what I tried was: original 7
> patches + the one liner + your patch blindly modified by me on the top
> of 3.9-rc4 and I'm still having twilight zone issues.

Not sure which one liner you refer to, but, if you haven't already done
so, please try with these fixes (queued in linux-next):

http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=a9cead0347283f3e72a39e7b76a3cc479b048e51
http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=4db64b89525ac357cba754c3120065adddd9ec31

I've been trying to reproduce your twilight zone problem on five
different machines now without any luck. Is there anything you're doing
to trigger the issue? Does the machine boot ok and then do weird things,
say after X starts, open some program, etc?

Thanks,
Davidlohr

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