From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Avi Kivity <avi@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Paul Turner <pjt@google.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Mike Galbraith <efault@gmx.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Dan Smith <danms@us.ibm.com>,
Bharata B Rao <bharata.rao@gmail.com>,
Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC][PATCH 00/26] sched/numa
Date: Tue, 20 Mar 2012 11:48:45 +0100 [thread overview]
Message-ID: <1332240525.18960.403.camel@twins> (raw)
In-Reply-To: <4F685960.4080904@redhat.com>
On Tue, 2012-03-20 at 12:18 +0200, Avi Kivity wrote:
> On 03/19/2012 10:03 PM, Peter Zijlstra wrote:
> > On Mon, 2012-03-19 at 14:16 +0200, Avi Kivity wrote:
> > > > Afaik we do not use dma engines for memory migration.
> > >
> > > We don't, but I think we should.
> >
> > ISTR we (the community) had this discussion once. I also seem to
> > remember the general consensus being that DMA engines would mostly
> > likely not be worth the effort, although I can't really recall the
> > specifics.
> >
> > Esp. for 4k pages the setup of the offload will likely be more expensive
> > than actually doing the memcpy.
>
> If you're copying a page, yes. If you're copying a large vma, the
> per-page setup cost is likely to be very low.
>
> Especially if you're copying across nodes.
But wouldn't you then have to wait for the entire copy to complete
before accessing any of the memory? That sounds like a way worse latency
hit than the per-page lazy-migrate.
next prev parent reply other threads:[~2012-03-20 10:49 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-16 14:40 [RFC][PATCH 00/26] sched/numa Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 01/26] mm, mpol: Re-implement check_*_range() using walk_page_range() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 02/26] mm, mpol: Remove NUMA_INTERLEAVE_HIT Peter Zijlstra
2012-07-06 10:32 ` Johannes Weiner
2012-07-06 13:46 ` [tip:sched/core] mm: Fix vmstat names-values off-by-one tip-bot for Johannes Weiner
2012-07-06 14:48 ` [RFC][PATCH 02/26] mm, mpol: Remove NUMA_INTERLEAVE_HIT Minchan Kim
2012-07-06 15:02 ` Peter Zijlstra
2012-07-06 14:54 ` Kyungmin Park
2012-07-06 15:00 ` Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 03/26] mm, mpol: add MPOL_MF_LAZY Peter Zijlstra
2012-03-23 11:50 ` Mel Gorman
2012-07-06 16:38 ` Rik van Riel
2012-07-06 20:04 ` Lee Schermerhorn
2012-07-06 20:27 ` Rik van Riel
2012-07-09 11:48 ` Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 04/26] mm, mpol: add MPOL_MF_NOOP Peter Zijlstra
2012-07-06 18:40 ` Rik van Riel
2012-03-16 14:40 ` [RFC][PATCH 05/26] mm, mpol: Check for misplaced page Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 06/26] mm: Migrate " Peter Zijlstra
2012-04-03 17:32 ` Dan Smith
2012-03-16 14:40 ` [RFC][PATCH 07/26] mm: Handle misplaced anon pages Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 08/26] mm, mpol: Simplify do_mbind() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 09/26] sched, mm: Introduce tsk_home_node() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 10/26] mm, mpol: Make mempolicy home-node aware Peter Zijlstra
2012-03-16 18:34 ` Christoph Lameter
2012-03-16 21:12 ` Peter Zijlstra
2012-03-19 13:53 ` Christoph Lameter
2012-03-19 14:05 ` Peter Zijlstra
2012-03-19 15:16 ` Christoph Lameter
2012-03-19 15:23 ` Peter Zijlstra
2012-03-19 15:31 ` Christoph Lameter
2012-03-19 17:09 ` Peter Zijlstra
2012-03-19 17:28 ` Peter Zijlstra
2012-03-19 19:06 ` Christoph Lameter
2012-03-19 20:28 ` Lee Schermerhorn
2012-03-19 21:21 ` Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 11/26] mm, mpol: Lazy migrate a process/vma Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 12/26] sched, mm: sched_{fork,exec} node assignment Peter Zijlstra
2012-06-15 18:16 ` Tony Luck
2012-06-20 19:12 ` [PATCH] sched: Fix build problems when CONFIG_NUMA=y and CONFIG_SMP=n Luck, Tony
2012-03-16 14:40 ` [RFC][PATCH 13/26] sched: Implement home-node awareness Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 14/26] sched, numa: Numa balancer Peter Zijlstra
2012-07-07 18:26 ` Rik van Riel
2012-07-09 12:05 ` Peter Zijlstra
2012-07-09 12:23 ` Peter Zijlstra
2012-07-09 12:40 ` Peter Zijlstra
2012-07-09 14:50 ` Rik van Riel
2012-07-08 18:35 ` Rik van Riel
2012-07-09 12:25 ` Peter Zijlstra
2012-07-09 14:54 ` Rik van Riel
2012-07-12 22:02 ` Rik van Riel
2012-07-13 14:45 ` Don Morris
2012-07-14 16:20 ` Rik van Riel
2012-03-16 14:40 ` [RFC][PATCH 15/26] sched, numa: Implement hotplug hooks Peter Zijlstra
2012-03-19 12:16 ` Srivatsa S. Bhat
2012-03-19 12:19 ` Peter Zijlstra
2012-03-19 12:27 ` Srivatsa S. Bhat
2012-03-16 14:40 ` [RFC][PATCH 16/26] sched, numa: Abstract the numa_entity Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 17/26] srcu: revert1 Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 18/26] srcu: revert2 Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 19/26] srcu: Implement call_srcu() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 20/26] mm, mpol: Introduce vma_dup_policy() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 21/26] mm, mpol: Introduce vma_put_policy() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 22/26] mm, mpol: Split and explose some mempolicy functions Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 23/26] sched, numa: Introduce sys_numa_{t,m}bind() Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 24/26] mm, mpol: Implement numa_group RSS accounting Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 25/26] sched, numa: Only migrate long-running entities Peter Zijlstra
2012-07-08 18:34 ` Rik van Riel
2012-07-09 12:26 ` Peter Zijlstra
2012-07-09 14:53 ` Rik van Riel
2012-07-09 14:55 ` Peter Zijlstra
2012-03-16 14:40 ` [RFC][PATCH 26/26] sched, numa: A few debug bits Peter Zijlstra
2012-03-16 18:25 ` [RFC] AutoNUMA alpha6 Andrea Arcangeli
2012-03-19 18:47 ` Peter Zijlstra
2012-03-19 19:02 ` Andrea Arcangeli
2012-03-20 23:41 ` Dan Smith
2012-03-21 1:00 ` Andrea Arcangeli
2012-03-21 2:12 ` Andrea Arcangeli
2012-03-21 4:01 ` Dan Smith
2012-03-21 12:49 ` Andrea Arcangeli
2012-03-21 22:05 ` Dan Smith
2012-03-21 22:52 ` Andrea Arcangeli
2012-03-21 23:13 ` Dan Smith
2012-03-21 23:41 ` Andrea Arcangeli
2012-03-22 0:17 ` Andrea Arcangeli
2012-03-22 13:58 ` Dan Smith
2012-03-22 14:27 ` Andrea Arcangeli
2012-03-22 18:49 ` Andrea Arcangeli
2012-03-22 18:56 ` Dan Smith
2012-03-22 19:11 ` Andrea Arcangeli
2012-03-23 14:15 ` Andrew Theurer
2012-03-23 16:01 ` Andrea Arcangeli
2012-03-25 13:30 ` Andrea Arcangeli
2012-03-21 7:12 ` Ingo Molnar
2012-03-21 12:08 ` Andrea Arcangeli
2012-03-21 7:53 ` Ingo Molnar
2012-03-21 12:17 ` Andrea Arcangeli
2012-03-19 9:57 ` [RFC][PATCH 00/26] sched/numa Avi Kivity
2012-03-19 11:12 ` Peter Zijlstra
2012-03-19 11:30 ` Peter Zijlstra
2012-03-19 11:39 ` Peter Zijlstra
2012-03-19 11:42 ` Avi Kivity
2012-03-19 11:59 ` Peter Zijlstra
2012-03-19 12:07 ` Avi Kivity
2012-03-19 12:09 ` Peter Zijlstra
2012-03-19 12:16 ` Avi Kivity
2012-03-19 20:03 ` Peter Zijlstra
2012-03-20 10:18 ` Avi Kivity
2012-03-20 10:48 ` Peter Zijlstra [this message]
2012-03-20 10:52 ` Avi Kivity
2012-03-20 11:07 ` Peter Zijlstra
2012-03-20 11:48 ` Avi Kivity
2012-03-19 12:20 ` Peter Zijlstra
2012-03-19 12:24 ` Avi Kivity
2012-03-19 15:44 ` Avi Kivity
2012-03-19 13:40 ` Andrea Arcangeli
2012-03-19 20:06 ` Peter Zijlstra
2012-03-19 13:04 ` Andrea Arcangeli
2012-03-19 13:26 ` Peter Zijlstra
2012-03-19 13:57 ` Andrea Arcangeli
2012-03-19 14:06 ` Avi Kivity
2012-03-19 14:30 ` Andrea Arcangeli
2012-03-19 18:42 ` Peter Zijlstra
2012-03-20 22:18 ` Rik van Riel
2012-03-21 16:50 ` Andrea Arcangeli
2012-04-02 16:34 ` Pekka Enberg
2012-04-02 16:55 ` Rik van Riel
2012-04-02 16:54 ` Pekka Enberg
2012-04-02 17:12 ` Pekka Enberg
2012-04-02 17:23 ` Pekka Enberg
2012-03-19 14:07 ` Peter Zijlstra
2012-03-19 14:34 ` Andrea Arcangeli
2012-03-19 18:41 ` Peter Zijlstra
2012-03-19 19:13 ` Peter Zijlstra
2012-03-19 14:07 ` Andrea Arcangeli
2012-03-19 19:05 ` Peter Zijlstra
2012-03-19 13:26 ` Peter Zijlstra
2012-03-19 14:16 ` Andrea Arcangeli
2012-03-19 13:29 ` Peter Zijlstra
2012-03-19 14:19 ` Andrea Arcangeli
2012-03-19 13:39 ` Peter Zijlstra
2012-03-19 14:20 ` Andrea Arcangeli
2012-03-19 20:17 ` Christoph Lameter
2012-03-19 20:28 ` Ingo Molnar
2012-03-19 20:43 ` Christoph Lameter
2012-03-19 21:34 ` Ingo Molnar
2012-03-20 0:05 ` Linus Torvalds
2012-03-20 7:31 ` Ingo Molnar
2012-03-21 22:53 ` Nish Aravamudan
2012-03-22 9:45 ` Peter Zijlstra
2012-03-22 10:34 ` Ingo Molnar
2012-03-24 1:41 ` Nish Aravamudan
2012-03-26 11:42 ` Peter Zijlstra
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