From: Rik van Riel <riel@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Steven Noonan <steven@uplinklabs.net>,
Linux Kernel mailing List <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Mel Gorman <mgorman@suse.de>, Alex Thorlton <athorlton@sgi.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [BISECTED] Linux 3.12.7 introduces page map handling regression
Date: Wed, 22 Jan 2014 13:39:32 -0500 [thread overview]
Message-ID: <52E01064.9090905@redhat.com> (raw)
In-Reply-To: <CA+55aFypCEec_15J-bPAuc1G=GtnQXjnnW5+dzwODq2DNW4Bsg@mail.gmail.com>
On 01/22/2014 01:24 PM, Linus Torvalds wrote:
> On Wed, Jan 22, 2014 at 10:07 AM, Rik van Riel <riel@redhat.com> wrote:
>>
>> The difference between a numa pte and a protnone pte is
>> the VMA permissions.
>
> If that is indeed the only difference, then we should damn well get
> rid of that f*cking stupid _PAGE_NUMA name entirely.
>
> It's misleading crap. Really. Just do a quick grep for that bit, and
> you see just *how* confused people are about it:
>
> #define _PAGE_NUMA _PAGE_PROTNONE
> ...
> if ((pte_flags(a) & (_PAGE_PROTNONE | _PAGE_NUMA)) &
>
> think about it. Just *THINK* about how broken that code is. The whole
> thing is a disaster. _PAGE_NUMA must die. It's shit.
The reason things are this way is that we were
not sure whether we can indeed use _PAGE_PROTNONE
for NUMA balancing on all architectures.
If we are sure that _PAGE_PROTNONE can be used
everywhere, I agree we should get rid of the whole
_PAGE_NUMA naming, and replace that ambiguous
code with some comments and documentation instead.
next prev parent reply other threads:[~2014-01-22 18:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-21 23:27 [BISECTED] Linux 3.12.7 introduces page map handling regression Steven Noonan
2014-01-22 1:49 ` Greg Kroah-Hartman
2014-01-22 2:47 ` Linus Torvalds
2014-01-22 3:20 ` Steven Noonan
2014-01-22 5:02 ` Konrad Rzeszutek Wilk
2014-01-22 7:29 ` Steven Noonan
2014-01-22 14:29 ` Daniel Borkmann
2014-01-22 20:18 ` Elena Ufimtseva
2014-01-22 20:33 ` Steven Noonan
2014-01-23 16:23 ` Elena Ufimtseva
2014-01-23 23:20 ` Steven Noonan
2014-01-24 4:28 ` Elena Ufimtseva
2014-01-24 11:05 ` David Vrabel
2014-01-24 13:38 ` Mel Gorman
2014-01-26 18:02 ` Elena Ufimtseva
2014-02-04 6:58 ` Elena Ufimtseva
2014-02-04 11:44 ` [PATCH] Subject: [PATCH] xen: Properly account for _PAGE_NUMA during xen pte translations Mel Gorman
2014-02-04 11:48 ` David Vrabel
2014-02-04 14:38 ` Konrad Rzeszutek Wilk
2014-01-22 18:07 ` [BISECTED] Linux 3.12.7 introduces page map handling regression Rik van Riel
2014-01-22 18:24 ` Linus Torvalds
2014-01-22 18:39 ` Rik van Riel [this message]
2014-01-24 11:43 ` Mel Gorman
2014-01-23 17:03 ` Mel Gorman
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