From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: William Lee Irwin III <wli@holomorphy.com>,
Andi Kleen <ak@suse.de>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Nick Piggin <nickpiggin@yahoo.com.au>,
"H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Why preallocate pmd in x86 32-bit PAE?
Date: Fri, 16 Nov 2007 11:14:36 -0800 [thread overview]
Message-ID: <473DEC1C.8080506@goop.org> (raw)
In-Reply-To: <alpine.LFD.0.9999.0711160921510.4260@woody.linux-foundation.org>
Linus Torvalds wrote:
> So don't do it. Just preallocate for the magic 4-entry PGD. You can make
> the special case just be something like
>
Yes, OK, it makes sense. Conceptually they would be dynamically
allocated and freed, but they'd just happen to start allocated, to avoid
the tlb flush of populating the pgd of an active pagetable. If you
happened to do a 1G munmap, it may end up freeing and reallocating them,
but that's going to be very rare. Either way, the other special cases
are avoided (though pgd_populate would still need to be correct, on the
offchance it gets invoked).
J
next prev parent reply other threads:[~2007-11-16 19:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-15 21:57 Why preallocate pmd in x86 32-bit PAE? Jeremy Fitzhardinge
2007-11-15 22:12 ` Linus Torvalds
2007-11-15 22:42 ` H. Peter Anvin
2007-11-16 0:40 ` William Lee Irwin III
2007-11-16 0:41 ` H. Peter Anvin
2007-11-16 11:16 ` Andi Kleen
2007-11-16 15:45 ` H. Peter Anvin
2007-11-16 15:53 ` Andi Kleen
2007-11-16 16:10 ` H. Peter Anvin
2007-11-16 17:12 ` Jeremy Fitzhardinge
2007-11-16 17:35 ` Linus Torvalds
2007-11-16 18:30 ` Jeremy Fitzhardinge
2007-11-16 19:14 ` Jeremy Fitzhardinge [this message]
2007-11-16 19:22 ` Linus Torvalds
2007-11-16 19:43 ` Jeremy Fitzhardinge
2007-11-16 17:45 ` H. Peter Anvin
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