From: Rik van Riel <riel@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
florian@openwrt.org, Borislav Petkov <borislav.petkov@amd.com>
Subject: Re: [PATCH 2/3] x86,mm: drop TLB flush from ptep_set_access_flags
Date: Sat, 27 Oct 2012 09:40:41 -0400 [thread overview]
Message-ID: <508BE459.2080406@redhat.com> (raw)
In-Reply-To: <20121026221254.7d32c8bf@pyramind.ukuu.org.uk>
On 10/26/2012 05:12 PM, Alan Cox wrote:
> On Fri, 26 Oct 2012 14:45:02 -0400
> Rik van Riel <riel@redhat.com> wrote:
>
>> Intel has an architectural guarantee that the TLB entry causing
>> a page fault gets invalidated automatically. This means
>> we should be able to drop the local TLB invalidation.
>>
>> Because of the way other areas of the page fault code work,
>> chances are good that all x86 CPUs do this. However, if
>> someone somewhere has an x86 CPU that does not invalidate
>> the TLB entry causing a page fault, this one-liner should
>> be easy to revert.
>
> This does not strike me as a good standard of validation for such a change
>
> At the very least we should have an ACK from AMD and from VIA, and
> preferably ping RDC and some of the other embedded folks. Given an AMD
> and VIA ACK I'd be fine. I doubt anyone knows any more what Cyrix CPUs
> did or cared about and I imagine H Peter or Linus can answer for
> Transmeta ;-)
Florian, would you happen to know who at RDC could be contacted
to verify whether a TLB entry causing a page fault gets
invalidated automatically, upon entering the page fault path?
Borislav, would you happen to know whether AMD (and VIA) CPUs
automatically invalidate TLB entries that cause page faults?
If you do not know, would you happen who to ask? :)
If these CPUs do not invalidate a TLB entry causing a page
fault (a write fault on a read-only PTE), then we may have to
change the kernel so flush_tlb_fix_spurious_fault does
something on the CPU models in question...
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
florian@openwrt.org, Borislav Petkov <borislav.petkov@amd.com>
Subject: Re: [PATCH 2/3] x86,mm: drop TLB flush from ptep_set_access_flags
Date: Sat, 27 Oct 2012 09:40:41 -0400 [thread overview]
Message-ID: <508BE459.2080406@redhat.com> (raw)
In-Reply-To: <20121026221254.7d32c8bf@pyramind.ukuu.org.uk>
On 10/26/2012 05:12 PM, Alan Cox wrote:
> On Fri, 26 Oct 2012 14:45:02 -0400
> Rik van Riel <riel@redhat.com> wrote:
>
>> Intel has an architectural guarantee that the TLB entry causing
>> a page fault gets invalidated automatically. This means
>> we should be able to drop the local TLB invalidation.
>>
>> Because of the way other areas of the page fault code work,
>> chances are good that all x86 CPUs do this. However, if
>> someone somewhere has an x86 CPU that does not invalidate
>> the TLB entry causing a page fault, this one-liner should
>> be easy to revert.
>
> This does not strike me as a good standard of validation for such a change
>
> At the very least we should have an ACK from AMD and from VIA, and
> preferably ping RDC and some of the other embedded folks. Given an AMD
> and VIA ACK I'd be fine. I doubt anyone knows any more what Cyrix CPUs
> did or cared about and I imagine H Peter or Linus can answer for
> Transmeta ;-)
Florian, would you happen to know who at RDC could be contacted
to verify whether a TLB entry causing a page fault gets
invalidated automatically, upon entering the page fault path?
Borislav, would you happen to know whether AMD (and VIA) CPUs
automatically invalidate TLB entries that cause page faults?
If you do not know, would you happen who to ask? :)
If these CPUs do not invalidate a TLB entry causing a page
fault (a write fault on a read-only PTE), then we may have to
change the kernel so flush_tlb_fix_spurious_fault does
something on the CPU models in question...
--
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next prev parent reply other threads:[~2012-10-27 13:38 UTC|newest]
Thread overview: 269+ 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 ` 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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 02/31] sched, numa, mm: Describe the NUMA scheduling problem formally Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 9:56 ` Mel Gorman
2012-11-01 9:56 ` Mel Gorman
2012-11-01 13:13 ` Rik van Riel
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
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 10:22 ` Mel Gorman
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 12:16 ` Peter Zijlstra
2012-10-25 20:10 ` Linus Torvalds
2012-10-25 20:10 ` Linus Torvalds
2012-10-26 6:24 ` [PATCH 04/31, v2] " Ingo Molnar
2012-10-26 6:24 ` Ingo Molnar
2012-11-01 10:42 ` [PATCH 04/31] " Mel Gorman
2012-11-01 10:42 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 05/31] x86/mm: Reduce tlb flushes from ptep_set_access_flags() Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-10-25 20:17 ` Linus Torvalds
2012-10-25 20:17 ` Linus Torvalds
2012-10-26 2:30 ` Rik van Riel
2012-10-26 2:30 ` Rik van Riel
2012-10-26 2:56 ` Linus Torvalds
2012-10-26 2:56 ` Linus Torvalds
2012-10-26 3:57 ` Rik van Riel
2012-10-26 3:57 ` Rik van Riel
2012-10-26 4:23 ` Linus Torvalds
2012-10-26 4:23 ` Linus Torvalds
2012-10-26 6:42 ` Ingo Molnar
2012-10-26 6:42 ` Ingo Molnar
2012-10-26 12:34 ` Michel Lespinasse
2012-10-26 12:34 ` Michel Lespinasse
2012-10-26 12:48 ` Andi Kleen
2012-10-26 12:48 ` Andi Kleen
2012-10-26 13:16 ` Rik van Riel
2012-10-26 13:16 ` Rik van Riel
2012-10-26 13:26 ` Ingo Molnar
2012-10-26 13:26 ` Ingo Molnar
2012-10-26 13:28 ` 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 18:44 ` Rik van Riel
2012-10-26 18:49 ` Linus Torvalds
2012-10-26 18:49 ` Linus Torvalds
2012-10-26 19:16 ` Rik van Riel
2012-10-26 19:16 ` Rik van Riel
2012-10-26 19:18 ` Linus Torvalds
2012-10-26 19:18 ` Linus Torvalds
2012-10-26 19:21 ` Rik van Riel
2012-10-26 19:21 ` Rik van Riel
2012-10-29 15:23 ` 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
2012-12-21 9:57 ` 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 18:45 ` Rik van Riel
2012-10-26 21:12 ` Alan Cox
2012-10-26 21:12 ` Alan Cox
2012-10-27 3:49 ` Rik van Riel
2012-10-27 3:49 ` Rik van Riel
2012-10-27 10:29 ` Ingo Molnar
2012-10-27 10:29 ` Ingo Molnar
2012-10-27 13:40 ` Rik van Riel [this message]
2012-10-27 13:40 ` Rik van Riel
2012-10-29 16:57 ` Borislav Petkov
2012-10-29 16:57 ` Borislav Petkov
2012-10-29 17:06 ` Linus Torvalds
2012-10-29 17:06 ` Linus Torvalds
2012-11-17 14:50 ` Borislav Petkov
2012-11-17 14:50 ` Borislav Petkov
2012-11-17 14:56 ` Linus Torvalds
2012-11-17 14:56 ` Linus Torvalds
2012-11-17 15:17 ` Borislav Petkov
2012-11-17 15:17 ` Borislav Petkov
2012-11-17 15:24 ` Rik van Riel
2012-11-17 15:24 ` Rik van Riel
2012-11-17 21:53 ` Shentino
2012-11-17 21:53 ` Shentino
2012-11-18 15:29 ` Michel Lespinasse
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 18:46 ` Rik van Riel
2012-10-26 18:48 ` Linus Torvalds
2012-10-26 18:48 ` Linus Torvalds
2012-10-26 18:53 ` Linus Torvalds
2012-10-26 18:53 ` Linus Torvalds
2012-10-26 18:57 ` Rik van Riel
2012-10-26 18:57 ` Rik van Riel
2012-10-26 19:16 ` Linus Torvalds
2012-10-26 19:16 ` Linus Torvalds
2012-10-26 19:33 ` [PATCH -v2 " Rik van Riel
2012-10-26 19:33 ` 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 13:23 ` Michel Lespinasse
2012-10-26 17:01 ` Linus Torvalds
2012-10-26 17:01 ` Linus Torvalds
2012-10-26 17:54 ` Rik van Riel
2012-10-26 17:54 ` Rik van Riel
2012-10-26 18:02 ` Linus Torvalds
2012-10-26 18:02 ` Linus Torvalds
2012-10-26 18:14 ` Rik van Riel
2012-10-26 18:14 ` Rik van Riel
2012-10-26 18:41 ` Linus Torvalds
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 07/31] sched, numa, mm, s390/thp: Implement pmd_pgprot() for s390 Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 10:49 ` Mel Gorman
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 ` 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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 10/31] mm/mpol: Remove NUMA_INTERLEAVE_HIT Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-10-25 20:58 ` Andi Kleen
2012-10-25 20:58 ` Andi Kleen
2012-10-26 7:59 ` Ingo Molnar
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
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 10:58 ` Mel Gorman
2012-11-01 10:58 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 12/31] mm/mpol: Add MPOL_MF_NOOP Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 11:10 ` Mel Gorman
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 14/31] mm/mpol: Create special PROT_NONE infrastructure Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 11:51 ` Mel Gorman
2012-11-01 11:51 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 15/31] mm/mpol: Add MPOL_MF_LAZY Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 12:01 ` Mel Gorman
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 17/31] mm/migrate: Introduce migrate_misplaced_page() Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 12:20 ` Mel Gorman
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 19/31] sched, numa, mm: Introduce tsk_home_node() Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 13:48 ` Mel Gorman
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
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 13:58 ` Mel Gorman
2012-11-01 13:58 ` Mel Gorman
2012-11-01 14:10 ` Don Morris
2012-11-01 14:10 ` Don Morris
2012-10-25 12:16 ` [PATCH 21/31] sched, numa, mm: Introduce sched_feat_numa() Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 14:00 ` Mel Gorman
2012-11-01 14:00 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 22/31] sched, numa, mm: Implement THP migration Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 14:16 ` Mel Gorman
2012-11-01 14:16 ` Mel Gorman
2012-10-25 12:16 ` [PATCH 23/31] sched, numa, mm: Implement home-node awareness Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 15:06 ` Mel Gorman
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
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 15:17 ` Mel Gorman
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 ` 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 12:16 ` Peter Zijlstra
2012-10-25 20:53 ` Linus Torvalds
2012-10-25 20:53 ` Linus Torvalds
2012-10-26 7:15 ` Ingo Molnar
2012-10-26 7:15 ` Ingo Molnar
2012-10-26 13:50 ` Ingo Molnar
2012-10-26 13:50 ` Ingo Molnar
2012-10-26 14:11 ` Peter Zijlstra
2012-10-26 14:11 ` Peter Zijlstra
2012-10-26 14:14 ` Ingo Molnar
2012-10-26 14:14 ` Ingo Molnar
2012-10-26 16:47 ` Linus Torvalds
2012-10-26 16:47 ` Linus Torvalds
2012-10-30 19:23 ` Rik van Riel
2012-10-30 19:23 ` Rik van Riel
2012-11-01 15:40 ` Mel Gorman
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 28/31] sched, numa, mm: Implement constant, per task Working Set Sampling (WSS) rate Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 15:48 ` Mel Gorman
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 ` Peter Zijlstra
2012-10-25 12:16 ` [PATCH 30/31] sched, numa, mm: Implement slow start for working set sampling Peter Zijlstra
2012-10-25 12:16 ` Peter Zijlstra
2012-11-01 15:52 ` Mel Gorman
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
2012-10-25 12:16 ` 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 9:08 ` Peter Zijlstra
2012-10-26 9:20 ` Ingo Molnar
2012-10-26 9:20 ` Ingo Molnar
2012-10-26 9:41 ` Zhouping Liu
2012-10-26 9:41 ` Zhouping Liu
2012-10-26 10:20 ` Zhouping Liu
2012-10-26 10:20 ` Zhouping Liu
2012-10-26 10:24 ` Ingo Molnar
2012-10-26 10:24 ` Ingo Molnar
2012-10-28 17:56 ` Johannes Weiner
2012-10-28 17:56 ` Johannes Weiner
2012-10-29 2:44 ` Zhouping Liu
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 6:50 ` Ingo Molnar
2012-10-29 8:24 ` Johannes Weiner
2012-10-29 8:24 ` Johannes Weiner
2012-10-29 8:36 ` Zhouping Liu
2012-10-29 8:36 ` Zhouping Liu
2012-10-29 11:15 ` Ingo Molnar
2012-10-29 11:15 ` Ingo Molnar
2012-10-30 6:29 ` [PATCH 00/31] numa/core patches Zhouping Liu
2012-10-30 6:29 ` Zhouping Liu
2012-10-31 0:48 ` Johannes Weiner
2012-10-31 0:48 ` Johannes Weiner
2012-10-31 7:26 ` Hugh Dickins
2012-10-31 7:26 ` Hugh Dickins
2012-10-31 13:15 ` Zhouping Liu
2012-10-31 13:15 ` Zhouping Liu
2012-10-31 17:31 ` Hugh Dickins
2012-10-31 17:31 ` Hugh Dickins
2012-11-01 13:41 ` Hugh Dickins
2012-11-01 13:41 ` Hugh Dickins
2012-11-02 3:23 ` Zhouping Liu
2012-11-02 3:23 ` Zhouping Liu
2012-11-02 23:06 ` Hugh Dickins
2012-11-02 23:06 ` Hugh Dickins
2012-10-30 12:20 ` Mel Gorman
2012-10-30 12:20 ` Mel Gorman
2012-10-30 15:28 ` Andrew Morton
2012-10-30 15:28 ` Andrew Morton
2012-10-30 16:59 ` Mel Gorman
2012-10-30 16:59 ` Mel Gorman
2012-11-03 11:04 ` Alex Shi
2012-11-03 11:04 ` Alex Shi
2012-11-03 12:21 ` Mel Gorman
2012-11-03 12:21 ` Mel Gorman
2012-11-10 2:47 ` Alex Shi
2012-11-10 2:47 ` Alex Shi
2012-11-12 9:50 ` Mel Gorman
2012-11-12 9:50 ` Mel Gorman
2012-11-09 8:51 ` Rik van Riel
2012-11-09 8:51 ` Rik van Riel
2012-11-05 17:11 ` Srikar Dronamraju
2012-11-05 17:11 ` Srikar Dronamraju
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