From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Hugh Dickins <hughd@google.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
linuxppc-dev@lists.ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: mmotm threatens ppc preemption again
Date: Mon, 21 Mar 2011 13:22:30 +1100 [thread overview]
Message-ID: <1300674150.2402.207.camel@pasglop> (raw)
In-Reply-To: <alpine.LSU.2.00.1103201901340.7257@sister.anvils>
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 ...
Cheers,
Ben.
next prev parent reply other threads:[~2011-03-21 2:23 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 [this message]
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
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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