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From: Jeremy Fitzhardinge <jeremy@goop•org>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: linuxppc-dev@lists•ozlabs.org,
	Andrew Morton <akpm@linux-foundation•org>,
	Hugh Dickins <hughd@google•com>,
	Peter Zijlstra <a.p.zijlstra@chello•nl>
Subject: Re: mmotm threatens ppc preemption again
Date: Thu, 31 Mar 2011 10:21:20 -0700	[thread overview]
Message-ID: <4D94B810.4000107@goop.org> (raw)
In-Reply-To: <1301532729.2407.16.camel@pasglop>

On 03/30/2011 05:52 PM, Benjamin Herrenschmidt wrote:
> We deal with preemption already since the PTL turns into a mutex on -rt,
> so we could bring that patch into mainline. The easiest approach however
> for now would be to not do the kernel batched updates on kernel
> (solution 4), and I can sort it out later if I want to enable it.
>
> The problem is that it's hard for me to "fix" that with the current
> accessors as arch_enter_lazy_mmu_mode() don't get any argument that
> could point me to which mm is being operated on.
>
> Jeremy, I haven't had a chance to look at your patches in detail, do
> you just use those accessors or do you create new ones for batching
> kernel updates in which case powerpc could just make them do nothing ?
>
> Else, we could have one patch that adds an mm argument accross the tree,
> it shouldn't be too hard.

No, its the same accessors for both, since the need to distinguish them
hasn't really come up.  Could you put a "if (preemptable()) return;"
guard in your implementations?

Otherwise I have no objections to passing the mm in (we'll probably just
continue to ignore the arg in x86-land).

Thanks,
    J

  reply	other threads:[~2011-03-31 17:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-20  4:11 mmotm threatens ppc preemption again Hugh Dickins
2011-03-20 23:53 ` Benjamin Herrenschmidt
2011-03-21  1:41   ` Hugh Dickins
2011-03-21  1:50     ` Benjamin Herrenschmidt
2011-03-21  2:20       ` Hugh Dickins
2011-03-21  2:22         ` Benjamin Herrenschmidt
2011-03-30 20:53           ` Andrew Morton
2011-03-30 21:07             ` Jeremy Fitzhardinge
2011-03-31  0:52               ` Benjamin Herrenschmidt
2011-03-31 17:21                 ` Jeremy Fitzhardinge [this message]
2011-03-31 20:38                   ` Benjamin Herrenschmidt
2011-05-18 23:29                     ` Jeremy Fitzhardinge
2011-03-21 11:24   ` Jeremy Fitzhardinge
2011-03-21 22:52     ` Benjamin Herrenschmidt
2011-03-22 13:34       ` Jeremy Fitzhardinge

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