From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rik van Riel <riel@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 04/31] x86/mm: Introduce pte_accessible()
Date: Thu, 1 Nov 2012 10:42:32 +0000 [thread overview]
Message-ID: <20121101104232.GP3888@suse.de> (raw)
In-Reply-To: <20121025124832.770994193@chello.nl>
On Thu, Oct 25, 2012 at 02:16:21PM +0200, Peter Zijlstra wrote:
> From: Rik van Riel <riel@redhat.com>
>
> We need pte_present to return true for _PAGE_PROTNONE pages, to indicate that
> the pte is associated with a page.
>
> However, for TLB flushing purposes, we would like to know whether the pte
> points to an actually accessible page. This allows us to skip remote TLB
> flushes for pages that are not actually accessible.
>
It feels like we are putting the cart before the horse to be taking TLB
flushing optimisations into account this early in the series. That
aside, what was wrong with the following patches?
autonuma: define _PAGE_NUMA
arch-dependant definition of a flag that happens to be PROT_NONE
on x86 but could be anything at all really which would help portability
autonuma: pte_numa() and pmd_numa()
makes pte_present do what you want
adds pte_numa and pmd_numa which potentially could have been
used instead of pte_accessible
autonuma: teach gup_fast about pmd_numa
sortof self-explanatory
and building on those? The arch-dependant nature of _PAGE_NUMA might have
avoided Linus sending the childrens college fund to the swear jar and
avoided this complaint;
===
because you have no idea if other architectures do
(a) the same trick as x86 does for PROT_NONE (I can already tell you
from a quick grep that ia64, m32r, m68k and sh do it)
(b) might not perhaps be caching non-present pte's anyway
====
The "autonuma: define _PAGE_NUMA" happens to use PROT_NONE but as an
implementation detail rather than by design and as a bonus point describes
what it is doing. The "autonuma" part in the title is misleading, it's
not autonuma-specific at all and could have been dropped or just renamed
"numa:"
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-11-01 10:42 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 12:16 [PATCH 00/31] numa/core patches Peter Zijlstra
2012-10-25 12:16 ` [PATCH 01/31] sched, numa, mm: Make find_busiest_queue() a method Peter Zijlstra
2012-10-25 12:16 ` [PATCH 02/31] sched, numa, mm: Describe the NUMA scheduling problem formally Peter Zijlstra
2012-11-01 9:56 ` Mel Gorman
2012-11-01 13:13 ` Rik van Riel
2012-10-25 12:16 ` [PATCH 03/31] mm/thp: Preserve pgprot across huge page split Peter Zijlstra
2012-11-01 10:22 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 04/31] x86/mm: Introduce pte_accessible() Peter Zijlstra
2012-10-25 20:10 ` Linus Torvalds
2012-10-26 6:24 ` [PATCH 04/31, v2] " Ingo Molnar
2012-11-01 10:42 ` Mel Gorman [this message]
2012-10-25 12:16 ` [PATCH 05/31] x86/mm: Reduce tlb flushes from ptep_set_access_flags() Peter Zijlstra
2012-10-25 20:17 ` Linus Torvalds
2012-10-26 2:30 ` Rik van Riel
2012-10-26 2:56 ` Linus Torvalds
2012-10-26 3:57 ` Rik van Riel
2012-10-26 4:23 ` Linus Torvalds
2012-10-26 6:42 ` Ingo Molnar
2012-10-26 12:34 ` Michel Lespinasse
2012-10-26 12:48 ` Andi Kleen
2012-10-26 13:16 ` Rik van Riel
2012-10-26 13:26 ` Ingo Molnar
2012-10-26 13:28 ` Ingo Molnar
2012-10-26 18:44 ` [PATCH 1/3] x86/mm: only do a local TLB flush in ptep_set_access_flags() Rik van Riel
2012-10-26 18:49 ` Linus Torvalds
2012-10-26 19:16 ` Rik van Riel
2012-10-26 19:18 ` Linus Torvalds
2012-10-26 19:21 ` Rik van Riel
2012-10-29 15:23 ` Rik van Riel
2012-12-21 9:57 ` trailing flush_tlb_fix_spurious_fault in handle_pte_fault (was Re: [PATCH 1/3] x86/mm: only do a local TLB flush in ptep_set_access_flags()) Vineet Gupta
2012-10-26 18:45 ` [PATCH 2/3] x86,mm: drop TLB flush from ptep_set_access_flags Rik van Riel
2012-10-26 21:12 ` Alan Cox
2012-10-27 3:49 ` Rik van Riel
2012-10-27 10:29 ` Ingo Molnar
2012-10-27 13:40 ` Rik van Riel
2012-10-29 16:57 ` Borislav Petkov
2012-10-29 17:06 ` Linus Torvalds
2012-11-17 14:50 ` Borislav Petkov
2012-11-17 14:56 ` Linus Torvalds
2012-11-17 15:17 ` Borislav Petkov
2012-11-17 15:24 ` Rik van Riel
2012-11-17 21:53 ` Shentino
2012-11-18 15:29 ` Michel Lespinasse
2012-10-26 18:46 ` [PATCH 3/3] mm,generic: only flush the local TLB in ptep_set_access_flags Rik van Riel
2012-10-26 18:48 ` Linus Torvalds
2012-10-26 18:53 ` Linus Torvalds
2012-10-26 18:57 ` Rik van Riel
2012-10-26 19:16 ` Linus Torvalds
2012-10-26 19:33 ` [PATCH -v2 " Rik van Riel
2012-10-26 13:23 ` [PATCH 05/31] x86/mm: Reduce tlb flushes from ptep_set_access_flags() Michel Lespinasse
2012-10-26 17:01 ` Linus Torvalds
2012-10-26 17:54 ` Rik van Riel
2012-10-26 18:02 ` Linus Torvalds
2012-10-26 18:14 ` Rik van Riel
2012-10-26 18:41 ` Linus Torvalds
2012-10-25 12:16 ` [PATCH 06/31] mm: Only flush the TLB when clearing an accessible pte Peter Zijlstra
2012-10-25 12:16 ` [PATCH 07/31] sched, numa, mm, s390/thp: Implement pmd_pgprot() for s390 Peter Zijlstra
2012-11-01 10:49 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 08/31] sched, numa, mm, MIPS/thp: Add pmd_pgprot() implementation Peter Zijlstra
2012-10-25 12:16 ` [PATCH 09/31] mm/pgprot: Move the pgprot_modify() fallback definition to mm.h Peter Zijlstra
2012-10-25 12:16 ` [PATCH 10/31] mm/mpol: Remove NUMA_INTERLEAVE_HIT Peter Zijlstra
2012-10-25 20:58 ` Andi Kleen
2012-10-26 7:59 ` Ingo Molnar
2012-10-25 12:16 ` [PATCH 11/31] mm/mpol: Make MPOL_LOCAL a real policy Peter Zijlstra
2012-11-01 10:58 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 12/31] mm/mpol: Add MPOL_MF_NOOP Peter Zijlstra
2012-11-01 11:10 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 13/31] mm/mpol: Check for misplaced page Peter Zijlstra
2012-10-25 12:16 ` [PATCH 14/31] mm/mpol: Create special PROT_NONE infrastructure Peter Zijlstra
2012-11-01 11:51 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 15/31] mm/mpol: Add MPOL_MF_LAZY Peter Zijlstra
2012-11-01 12:01 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 16/31] numa, mm: Support NUMA hinting page faults from gup/gup_fast Peter Zijlstra
2012-10-25 12:16 ` [PATCH 17/31] mm/migrate: Introduce migrate_misplaced_page() Peter Zijlstra
2012-11-01 12:20 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 18/31] mm/mpol: Use special PROT_NONE to migrate pages Peter Zijlstra
2012-10-25 12:16 ` [PATCH 19/31] sched, numa, mm: Introduce tsk_home_node() Peter Zijlstra
2012-11-01 13:48 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 20/31] sched, numa, mm/mpol: Make mempolicy home-node aware Peter Zijlstra
2012-11-01 13:58 ` Mel Gorman
2012-11-01 14:10 ` Don Morris
2012-10-25 12:16 ` [PATCH 21/31] sched, numa, mm: Introduce sched_feat_numa() Peter Zijlstra
2012-11-01 14:00 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 22/31] sched, numa, mm: Implement THP migration Peter Zijlstra
2012-11-01 14:16 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 23/31] sched, numa, mm: Implement home-node awareness Peter Zijlstra
2012-11-01 15:06 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 24/31] sched, numa, mm: Introduce last_nid in the pageframe Peter Zijlstra
2012-11-01 15:17 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 25/31] sched, numa, mm/mpol: Add_MPOL_F_HOME Peter Zijlstra
2012-10-25 12:16 ` [PATCH 26/31] sched, numa, mm: Add fault driven placement and migration policy Peter Zijlstra
2012-10-25 20:53 ` Linus Torvalds
2012-10-26 7:15 ` Ingo Molnar
2012-10-26 13:50 ` Ingo Molnar
2012-10-26 14:11 ` Peter Zijlstra
2012-10-26 14:14 ` Ingo Molnar
2012-10-26 16:47 ` Linus Torvalds
2012-10-30 19:23 ` Rik van Riel
2012-11-01 15:40 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 27/31] sched, numa, mm: Add credits for NUMA placement Peter Zijlstra
2012-10-25 12:16 ` [PATCH 28/31] sched, numa, mm: Implement constant, per task Working Set Sampling (WSS) rate Peter Zijlstra
2012-11-01 15:48 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 29/31] sched, numa, mm: Add NUMA_MIGRATION feature flag Peter Zijlstra
2012-10-25 12:16 ` [PATCH 30/31] sched, numa, mm: Implement slow start for working set sampling Peter Zijlstra
2012-11-01 15:52 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 31/31] sched, numa, mm: Add memcg support to do_huge_pmd_numa_page() Peter Zijlstra
2012-10-26 9:07 ` [PATCH 00/31] numa/core patches Zhouping Liu
2012-10-26 9:08 ` Peter Zijlstra
2012-10-26 9:20 ` Ingo Molnar
2012-10-26 9:41 ` Zhouping Liu
2012-10-26 10:20 ` Zhouping Liu
2012-10-26 10:24 ` Ingo Molnar
2012-10-28 17:56 ` Johannes Weiner
2012-10-29 2:44 ` Zhouping Liu
2012-10-29 6:50 ` [PATCH] sched, numa, mm: Add memcg support to do_huge_pmd_numa_page() Ingo Molnar
2012-10-29 8:24 ` Johannes Weiner
2012-10-29 8:36 ` Zhouping Liu
2012-10-29 11:15 ` Ingo Molnar
2012-10-30 6:29 ` [PATCH 00/31] numa/core patches Zhouping Liu
2012-10-31 0:48 ` Johannes Weiner
2012-10-31 7:26 ` Hugh Dickins
2012-10-31 13:15 ` Zhouping Liu
2012-10-31 17:31 ` Hugh Dickins
2012-11-01 13:41 ` Hugh Dickins
2012-11-02 3:23 ` Zhouping Liu
2012-11-02 23:06 ` Hugh Dickins
2012-10-30 12:20 ` Mel Gorman
2012-10-30 15:28 ` Andrew Morton
2012-10-30 16:59 ` Mel Gorman
2012-11-03 11:04 ` Alex Shi
2012-11-03 12:21 ` Mel Gorman
2012-11-10 2:47 ` Alex Shi
2012-11-12 9:50 ` Mel Gorman
2012-11-09 8:51 ` Rik van Riel
2012-11-05 17:11 ` Srikar Dronamraju
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