From: Mel Gorman <mgorman@suse.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Turner <pjt@google.com>,
Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
Christoph Lameter <cl@linux.com>, Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH, v2] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones
Date: Wed, 21 Nov 2012 11:40:26 +0000 [thread overview]
Message-ID: <20121121114025.GY8218@suse.de> (raw)
In-Reply-To: <20121120160918.GA18167@gmail.com>
On Tue, Nov 20, 2012 at 05:09:18PM +0100, Ingo Molnar wrote:
>
> Ok, the patch withstood a bit more testing as well. Below is a
> v2 version of it, with a couple of cleanups (no functional
> changes).
>
> Thanks,
>
> Ingo
>
> ----------------->
> Subject: mm, numa: Turn 4K pte NUMA faults into effective hugepage ones
> From: Ingo Molnar <mingo@kernel.org>
> Date: Tue Nov 20 15:48:26 CET 2012
>
> Reduce the 4K page fault count by looking around and processing
> nearby pages if possible.
>
> To keep the logic and cache overhead simple and straightforward
> we do a couple of simplifications:
>
> - we only scan in the HPAGE_SIZE range of the faulting address
> - we only go as far as the vma allows us
>
> Also simplify the do_numa_page() flow while at it and fix the
> previous double faulting we incurred due to not properly fixing
> up freshly migrated ptes.
>
> Suggested-by: Mel Gorman <mgorman@suse.de>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Hugh Dickins <hughd@google.com>
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> ---
> mm/memory.c | 99 ++++++++++++++++++++++++++++++++++++++----------------------
> 1 file changed, 64 insertions(+), 35 deletions(-)
>
This is functionally similar to what balancenuma does but there is one key
difference worth noting. I only mark the PMD pmd_numa if all the pages
pointed to by the updated[*] PTEs underneath are on the same node. The
intention is that if the workload is converged on a PMD boundary then a
migration of all the pages underneath will be remote->local copies. If the
workload is not converged on a PMD boundary and you handle all the faults
then you are potentially incurring remote->remote copies.
It also means that if the workload is not converged on the PMD boundary
then a PTE fault is just one page. With yours, it will be the full PMD
every time, right?
[*] Note I said only the updated ptes are checked. I do not check every
PTE underneath. I could but felt the benefit would be marginal.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-11-21 11:40 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-19 2:14 [PATCH 00/27] Latest numa/core release, v16 Ingo Molnar
2012-11-19 2:14 ` [PATCH 01/27] mm/generic: Only flush the local TLB in ptep_set_access_flags() Ingo Molnar
2012-11-19 2:14 ` [PATCH 02/27] x86/mm: Only do a local tlb flush " Ingo Molnar
2012-11-19 2:14 ` [PATCH 03/27] x86/mm: Introduce pte_accessible() Ingo Molnar
2012-11-19 2:14 ` [PATCH 04/27] mm: Only flush the TLB when clearing an accessible pte Ingo Molnar
2012-11-19 2:14 ` [PATCH 05/27] x86/mm: Completely drop the TLB flush from ptep_set_access_flags() Ingo Molnar
2012-11-19 2:14 ` [PATCH 06/27] mm: Count the number of pages affected in change_protection() Ingo Molnar
2012-11-19 2:14 ` [PATCH 07/27] mm: Optimize the TLB flush of sys_mprotect() and change_protection() users Ingo Molnar
2012-11-19 2:14 ` [PATCH 08/27] sched, numa, mm: Add last_cpu to page flags Ingo Molnar
2012-11-19 2:14 ` [PATCH 09/27] sched, mm, numa: Create generic NUMA fault infrastructure, with architectures overrides Ingo Molnar
2012-11-19 2:14 ` [PATCH 10/27] sched: Make find_busiest_queue() a method Ingo Molnar
2012-11-19 2:14 ` [PATCH 11/27] sched, numa, mm: Describe the NUMA scheduling problem formally Ingo Molnar
2012-11-19 2:14 ` [PATCH 12/27] numa, mm: Support NUMA hinting page faults from gup/gup_fast Ingo Molnar
2012-11-19 2:14 ` [PATCH 13/27] mm/migrate: Introduce migrate_misplaced_page() Ingo Molnar
2012-11-19 2:14 ` [PATCH 14/27] sched, numa, mm, arch: Add variable locality exception Ingo Molnar
2012-11-19 2:14 ` [PATCH 15/27] sched, numa, mm: Add credits for NUMA placement Ingo Molnar
2012-11-19 2:14 ` [PATCH 16/27] sched, mm, x86: Add the ARCH_SUPPORTS_NUMA_BALANCING flag Ingo Molnar
2012-11-19 2:14 ` [PATCH 17/27] sched, numa, mm: Add the scanning page fault machinery Ingo Molnar
2012-11-19 2:14 ` [PATCH 18/27] sched: Add adaptive NUMA affinity support Ingo Molnar
2012-11-19 2:14 ` [PATCH 19/27] sched: Implement constant, per task Working Set Sampling (WSS) rate Ingo Molnar
2012-11-19 2:14 ` [PATCH 20/27] sched, numa, mm: Count WS scanning against present PTEs, not virtual memory ranges Ingo Molnar
2012-11-19 2:14 ` [PATCH 21/27] sched: Implement slow start for working set sampling Ingo Molnar
2012-11-19 2:14 ` [PATCH 22/27] sched, numa, mm: Interleave shared tasks Ingo Molnar
2012-11-19 2:14 ` [PATCH 23/27] sched: Implement NUMA scanning backoff Ingo Molnar
2012-11-19 2:14 ` [PATCH 24/27] sched: Improve convergence Ingo Molnar
2012-11-19 2:14 ` [PATCH 25/27] sched: Introduce staged average NUMA faults Ingo Molnar
2012-11-19 2:14 ` [PATCH 26/27] sched: Track groups of shared tasks Ingo Molnar
2012-11-19 2:14 ` [PATCH 27/27] sched: Use the best-buddy 'ideal cpu' in balancing decisions Ingo Molnar
2012-11-19 16:29 ` [PATCH 00/27] Latest numa/core release, v16 Mel Gorman
2012-11-19 19:13 ` Ingo Molnar
2012-11-19 21:18 ` Mel Gorman
2012-11-19 22:36 ` Ingo Molnar
2012-11-19 23:00 ` Mel Gorman
2012-11-20 0:41 ` Rik van Riel
2012-11-21 10:58 ` Mel Gorman
2012-11-20 1:02 ` Linus Torvalds
2012-11-20 7:17 ` Ingo Molnar
2012-11-20 7:37 ` David Rientjes
2012-11-20 7:48 ` Ingo Molnar
2012-11-20 8:01 ` Ingo Molnar
2012-11-20 8:11 ` David Rientjes
2012-11-21 11:14 ` Mel Gorman
2012-11-20 10:20 ` Mel Gorman
2012-11-20 10:47 ` Mel Gorman
2012-11-20 15:29 ` [PATCH] mm, numa: Turn 4K pte NUMA faults into effective hugepage ones Ingo Molnar
2012-11-20 16:09 ` [PATCH, v2] " Ingo Molnar
2012-11-20 16:31 ` Rik van Riel
2012-11-20 16:52 ` Ingo Molnar
2012-11-21 12:08 ` Mel Gorman
2012-11-21 8:12 ` Ingo Molnar
2012-11-21 2:41 ` David Rientjes
2012-11-21 9:34 ` Ingo Molnar
2012-11-21 11:40 ` Mel Gorman [this message]
2012-11-23 1:26 ` Alex Shi
2012-11-20 17:56 ` numa/core regressions fixed - more testers wanted Ingo Molnar
2012-11-21 1:54 ` Andrew Theurer
2012-11-21 3:22 ` Rik van Riel
2012-11-21 4:10 ` Hugh Dickins
2012-11-21 17:59 ` Andrew Theurer
2012-11-21 11:52 ` Mel Gorman
2012-11-21 22:15 ` Andrew Theurer
2012-11-21 3:33 ` David Rientjes
2012-11-21 9:38 ` Ingo Molnar
2012-11-21 11:06 ` Ingo Molnar
2012-11-21 8:39 ` Alex Shi
2012-11-22 1:21 ` Ingo Molnar
2012-11-23 13:31 ` Ingo Molnar
2012-11-23 15:23 ` Alex Shi
2012-11-26 2:11 ` Alex Shi
2012-11-28 14:21 ` Alex Shi
2012-11-20 10:40 ` [PATCH 00/27] Latest numa/core release, v16 Ingo Molnar
2012-11-20 11:40 ` Mel Gorman
2012-11-21 10:38 ` Mel Gorman
2012-11-21 19:37 ` Andrea Arcangeli
2012-11-21 19:56 ` Mel Gorman
2012-11-19 20:07 ` Ingo Molnar
2012-11-19 21:37 ` Mel Gorman
2012-11-20 0:50 ` David Rientjes
2012-11-20 1:05 ` David Rientjes
2012-11-20 6:00 ` Ingo Molnar
2012-11-20 6:20 ` David Rientjes
2012-11-20 7:44 ` Ingo Molnar
2012-11-20 7:48 ` Paul Turner
2012-11-20 8:20 ` David Rientjes
2012-11-20 9:06 ` Ingo Molnar
2012-11-20 9:41 ` [patch] x86/vsyscall: Add Kconfig option to use native vsyscalls, switch to it Ingo Molnar
2012-11-20 23:01 ` Andy Lutomirski
2012-11-21 0:43 ` David Rientjes
2012-11-20 12:02 ` [PATCH] x86/mm: Don't flush the TLB on #WP pmd fixups Ingo Molnar
2012-11-20 12:31 ` Ingo Molnar
2012-11-21 11:47 ` Mel Gorman
2012-11-21 1:22 ` David Rientjes
2012-11-21 17:02 ` [PATCH 00/27] Latest numa/core release, v16 Linus Torvalds
2012-11-21 17:10 ` Ingo Molnar
2012-11-21 17:20 ` Ingo Molnar
2012-11-22 4:31 ` David Rientjes
2012-11-21 17:40 ` Ingo Molnar
2012-11-21 22:04 ` Linus Torvalds
2012-11-21 22:46 ` Ingo Molnar
2012-11-21 17:45 ` Rik van Riel
2012-11-21 18:04 ` Ingo Molnar
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