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From: Don Morris <don.morris@hp.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	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,
	Paul Turner <pjt@google.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 20/31] sched, numa, mm/mpol: Make mempolicy home-node aware
Date: Thu, 01 Nov 2012 07:10:30 -0700	[thread overview]
Message-ID: <509282D6.8010808@hp.com> (raw)
In-Reply-To: <20121101135813.GX3888@suse.de>

On 11/01/2012 06:58 AM, Mel Gorman wrote:
> On Thu, Oct 25, 2012 at 02:16:37PM +0200, Peter Zijlstra wrote:
>> Add another layer of fallback policy to make the home node concept
>> useful from a memory allocation PoV.
>>
>> This changes the mpol order to:
>>
>>  - vma->vm_ops->get_policy	[if applicable]
>>  - vma->vm_policy		[if applicable]
>>  - task->mempolicy
>>  - tsk_home_node() preferred	[NEW]
>>  - default_policy
>>
>> Note that the tsk_home_node() policy has Migrate-on-Fault enabled to
>> facilitate efficient on-demand memory migration.
>>
> 
> Makes sense and it looks like a VMA policy, if set, will still override
> the home_node policy as you'd expect. At some point this may need to cope
> with node hot-remove. Also, at some point this must be dealing with the
> case where mbind() is called but the home_node is not in the nodemask.
> Does that happen somewhere else in the series? (maybe I'll see it later)
> 

I'd expect one of the first things to be done in the sequence of
hot-removing a node would be to take the cpus offline (at least
out of being schedulable). Hence the tasks would be migrated
to other nodes/processors, which should result in a home node
update the same as if the scheduler had simply chosen a better
home for them anyway. The memory would then migrate either
via the home node change by the tasks themselves or via
migration to evacuate the outgoing node (with the preferred
migration target using the new home node).

As long as no one wants to do something crazy like offline
a node before taking the resources away from the scheduler
and memory management, it should all work out.

Don Morris

  reply	other threads:[~2012-11-01 14:10 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   ` [PATCH 04/31] " 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 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 [this message]
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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