From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
LinuxPPC-dev <linuxppc-dev@lists.ozlabs.org>,
Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
Hugh Dickins <hughd@google.com>, Dave Jones <davej@redhat.com>,
Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@redhat.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Sasha Levin <sasha.levin@oracle.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing
Date: Thu, 20 Nov 2014 11:54:06 -0800 [thread overview]
Message-ID: <CA+55aFwV80r66w4RmtY-MAUGkwmfBJe+C5KFD3ZnNgYb_KbBpQ@mail.gmail.com> (raw)
In-Reply-To: <1416478790-27522-3-git-send-email-mgorman@suse.de>
On Thu, Nov 20, 2014 at 2:19 AM, Mel Gorman <mgorman@suse.de> wrote:
> This is a preparatory patch that introduces protnone helpers for automatic
> NUMA balancing.
Oh, I hadn't noticed that you had renamed these things. It was
probably already true in your V1 version.
I do *not* think that "pte_protnone_numa()" makes sense as a name. It
only confuses people to think that there is still/again something
NUMA-special about the PTE. The whole point of the protnone changes
was to make it really very very clear that from a hardware standpoint,
this is *exactly* about protnone, and nothing else.
The fact that we then use protnone PTE's for numa faults is a VM
internal issue, it should *not* show up in the architecture page table
helpers.
I'm not NAK'ing this name, but I really think it's a very important
part of the whole patch series - to stop the stupid confusion about
NUMA entries. As far as the page tables are concerned, this has
absolutely _zero_ to do with NUMA.
We made that mistake once. We're fixing it. Let the naming *show* that
it's fixed, and this is "pte_protnone()".
The places that use this for NUMA handling might have a comment or
something. But they'll be in the VM where this matters, not in the
architecture page table description files. The comment would be
something like "if the vma is accessible, but the PTE is marked
protnone, this is a autonuma entry".
Linus
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next prev parent reply other threads:[~2014-11-20 19:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-20 10:19 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Mel Gorman
2014-11-20 10:19 ` [PATCH 01/10] mm: numa: Do not dereference pmd outside of the lock during NUMA hinting fault Mel Gorman
2014-11-20 10:19 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2014-11-20 19:54 ` Linus Torvalds [this message]
2014-11-21 9:35 ` Mel Gorman
2014-11-20 10:19 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2014-11-20 10:38 ` David Laight
2014-11-20 10:47 ` Mel Gorman
2014-11-21 5:28 ` Aneesh Kumar K.V
2014-11-20 10:19 ` [PATCH 04/10] ppc64: Add paranoid warnings for unexpected DSISR_PROTFAULT Mel Gorman
2014-11-20 10:19 ` [PATCH 05/10] mm: Convert p[te|md]_mknonnuma and remaining page table manipulations Mel Gorman
2014-11-20 10:19 ` [PATCH 06/10] mm: Remove remaining references to NUMA hinting bits and helpers Mel Gorman
2014-11-20 10:19 ` [PATCH 07/10] mm: numa: Do not trap faults on the huge zero page Mel Gorman
2014-11-20 10:19 ` [PATCH 08/10] x86: mm: Restore original pte_special check Mel Gorman
2014-11-20 10:19 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
2014-11-20 10:19 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
2014-11-20 21:50 ` [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Sasha Levin
2014-11-21 9:31 ` Mel Gorman
2014-11-21 13:57 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v3 Mel Gorman
2014-11-21 13:57 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2014-12-01 22:38 ` Benjamin Herrenschmidt
2014-12-02 10:12 ` Mel Gorman
2014-12-04 11:24 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v4 Mel Gorman
2014-12-04 11:24 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2015-01-05 10:54 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v5 Mel Gorman
2015-01-05 10:54 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
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