From: "'David Gibson'" <david@gibson.dropbear.id.au>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: IA64 non-contiguous memory space bugs
Date: Wed, 22 Feb 2006 13:15:10 +1100 [thread overview]
Message-ID: <20060222021510.GC23574@localhost.localdomain> (raw)
In-Reply-To: <200602220132.k1M1Vxg09552@unix-os.sc.intel.com>
On Tue, Feb 21, 2006 at 05:31:59PM -0800, Chen, Kenneth W wrote:
> David Gibson wrote on Tuesday, February 21, 2006 4:14 PM
> > Second problem is in the hugepage logic in free_pgtables()
> > (mm/memory.c). As far as I can tell it's complete crap, and only
> > works by accident, for different accidental reasons on ppc64 and ia64,
> > the only archs that have a non-trivial is_hugepage_only_range().
> > Except that I'm not sure it does entirely work by accident on ia64:
> > suppose a process has a hugepage mapping that begins some way after
> > the beginning of the hugepage address range. Before
> > hugetlb_free_pgd_range() gets called on that area, it will be called
> > on the next normal page VMA down - but with an end address at the
> > beginning of the hugepage VMA and so extending into the hugepage
> > address range. I don't really understand the ia64 pagetable mapping
> > stuff well enough to tell if that's dangerous or not.
>
> I don't see any problem in the ia64 code. The start and end address is
> what the vma specified. Floor and ceiling is just a hint for free_pgtables()
> to free any left over page tables between vma holes (to prev and next).
> As far as I can tell, the code looks fine.
Ah, yes, I see now. free_pgd_range() only iterates through to end,
not ceiling so it should be fine.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
next prev parent reply other threads:[~2006-02-22 2:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 0:13 IA64 non-contiguous memory space bugs David Gibson
2006-02-22 0:39 ` David S. Miller
2006-02-22 2:17 ` David Gibson
2006-02-22 1:31 ` Chen, Kenneth W
2006-02-22 1:51 ` Chen, Kenneth W
2006-02-22 2:25 ` 'David Gibson'
2006-02-22 2:45 ` Chen, Kenneth W
2006-02-22 16:35 ` Hugh Dickins
2006-02-22 23:49 ` 'David Gibson'
2006-02-23 20:13 ` Hugh Dickins
2006-02-24 0:11 ` 'David Gibson'
2006-02-24 1:14 ` Chen, Kenneth W
2006-02-24 2:46 ` 'David Gibson'
2006-02-22 2:15 ` 'David Gibson' [this message]
2006-02-22 2:53 ` Chen, Kenneth W
2006-02-22 3:55 ` David Mosberger-Tang
2006-02-22 4:02 ` David Gibson
2006-02-22 16:19 ` Chen, Kenneth W
2006-02-22 23:26 ` 'David Gibson'
2006-02-22 3:01 Zhang, Yanmin
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