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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Nick Piggin <npiggin@kernel.dk>
Cc: "Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Could we do immediate pte zaps in vunmap?
Date: Fri, 26 Nov 2010 00:10:51 -0800	[thread overview]
Message-ID: <4CEF6B8B.8080206@goop.org> (raw)

What if vm_unmap_ram() and co. immediately zeroed out the ptes, but
lazily deferred the tlb flushes?  It seems to me there's no benefit in
batching up the pte clearing since that can't be amortized like the tlb
flush.

I think that would solve the problem we have with the interactions
between lazy unmap and Xen.  The issue is having stray pte entries
around (because Xen keeps track of those as part of its page-type
mechanism), but stale tlb entries are no problem.

Thanks,
    J

             reply	other threads:[~2010-11-26  8:10 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-26  8:10 Jeremy Fitzhardinge [this message]
2010-11-27 10:36 ` Could we do immediate pte zaps in vunmap? Nick Piggin
2010-11-29 20:32   ` [PATCH RFC] vmalloc: eagerly clear ptes on vunmap Jeremy Fitzhardinge
2010-11-29 20:32     ` Jeremy Fitzhardinge
2010-11-30 12:42     ` Nick Piggin
2010-11-30 12:42       ` Nick Piggin
2010-11-30 17:45       ` Jeremy Fitzhardinge
2010-11-30 17:45         ` Jeremy Fitzhardinge
2010-12-01  0:29     ` Andrew Morton
2010-12-01  0:29       ` Andrew Morton
2010-12-01  3:09       ` Jeremy Fitzhardinge
2010-12-01  3:09         ` Jeremy Fitzhardinge
2010-12-01  3:23         ` Andrew Morton
2010-12-01  3:23           ` Andrew Morton
2010-12-01  8:16           ` Jeremy Fitzhardinge
2010-12-01  8:16             ` Jeremy Fitzhardinge

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