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From: Andrew Morton <akpm@linux-foundation.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Hugh Dickins <hughd@google.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: mmotm threatens ppc preemption again
Date: Wed, 30 Mar 2011 13:53:32 -0700	[thread overview]
Message-ID: <20110330135332.9c322e40.akpm@linux-foundation.org> (raw)
In-Reply-To: <1300674150.2402.207.camel@pasglop>

On Mon, 21 Mar 2011 13:22:30 +1100
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> On Sun, 2011-03-20 at 19:20 -0700, Hugh Dickins wrote:
> > > As long as the races to avoid are between map/unmap vs. access, yes, it
> > > -should- be fine, and we used to not do demand faulting on kernel space
> > > (but for how long ?). I'm wondering why we don't just stick a ptl in
> > > there or is there a good reason why we can't ?
> > 
> > We can - but we usually prefer to avoid unnecessary locking.
> > An arch function which locks init_mm.page_table_lock on powerpc,
> > but does nothing on others? 
> 
> That still means gratuitous differences between how the normal and
> kernel page tables are handled. Maybe that's not worth bothering ...

So what will we do here?  I still have

mm-remove-unused-token-argument-from-apply_to_page_range-callback.patch
mm-add-apply_to_page_range_batch.patch
ioremap-use-apply_to_page_range_batch-for-ioremap_page_range.patch
vmalloc-use-plain-pte_clear-for-unmaps.patch
vmalloc-use-apply_to_page_range_batch-for-vunmap_page_range.patch
vmalloc-use-apply_to_page_range_batch-for-vmap_page_range_noflush.patch
vmalloc-use-apply_to_page_range_batch-in-alloc_vm_area.patch
xen-mmu-use-apply_to_page_range_batch-in-xen_remap_domain_mfn_range.patch
xen-grant-table-use-apply_to_page_range_batch.patch

floating around and at some stage they may cause merge problems.

  reply	other threads:[~2011-03-30 20:54 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 [this message]
2011-03-30 21:07             ` Jeremy Fitzhardinge
2011-03-31  0:52               ` Benjamin Herrenschmidt
2011-03-31 17:21                 ` Jeremy Fitzhardinge
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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