From: David Rientjes <rientjes@google.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Christoph Lameter <cl@linux-foundation.org>,
Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 5/7] Add /proc trigger for memory compaction
Date: Wed, 20 Jan 2010 12:48:05 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1001201241540.6440@chino.kir.corp.google.com> (raw)
In-Reply-To: <20100120094813.GC5154@csn.ul.ie>
On Wed, 20 Jan 2010, Mel Gorman wrote:
> > With Lee's work on mempolicy-constrained hugepage allocations, there is a
> > use-case for this explicit trigger to be exported via sysfs in the
> > longterm:
>
> True, although the per-node structures are only available on NUMA making
> it necessary to have two interfaces. The per-node one is handy enough
> because it would be just
>
> /sys/devices/system/node/nodeX/compact_node
> When written to, this node is compacted by the writing process
>
> But there does not appear to be a "good" way of having a non-NUMA
> interface. /sys/devices/system/node does not exist .... Does anyone
> remember why !NUMA does not have a /sys/devices/system/node/node0? Is
> there a good reason or was there just no point?
>
There doesn't seem to be a usecase for a fake node0 sysfs entry since it
would be a duplication of procfs.
I think it would be best to create a global /proc/sys/vm/compact trigger
that would walk all "compactable" zones system-wide and then a per-node
/sys/devices/system/node/nodeX/compact trigger for that particular node,
both with permissions 0200.
It would be helpful to be able to determine what is "compactable" at the
same time by adding both global and per-node "compact_order" tunables that
would default to HUGETLB_PAGE_ORDER. Then, the corresponding "compact"
trigger would only do work if fill_contig_page_info() shows
!free_blocks_suitable for either all zones (global trigger) or each zone
in the node's zonelist (per-node trigger).
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next prev parent reply other threads:[~2010-01-20 20:48 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-06 16:26 [RFC-PATCH 0/7] Memory Compaction v1 Mel Gorman
2010-01-06 16:26 ` [PATCH 1/7] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA Mel Gorman
2010-01-07 21:46 ` David Rientjes
2010-01-07 22:04 ` Christoph Lameter
2010-01-19 13:00 ` Mel Gorman
2010-01-06 16:26 ` [PATCH 2/7] Export unusable free space index via /proc/pagetypeinfo Mel Gorman
2010-01-06 17:10 ` Adam Litke
2010-01-06 17:29 ` Mel Gorman
2010-01-06 23:21 ` Tim Pepper
2010-01-28 22:27 ` David Rientjes
2010-02-05 10:23 ` Mel Gorman
2010-02-05 21:40 ` David Rientjes
2010-02-08 12:10 ` Mel Gorman
2010-01-06 16:26 ` [PATCH 3/7] Export fragmentation " Mel Gorman
2010-01-06 16:26 ` [PATCH 4/7] Memory compaction core Mel Gorman
2010-01-06 17:50 ` Mel Gorman
2010-01-06 18:22 ` Mel Gorman
2010-01-06 21:37 ` Andi Kleen
2010-01-06 22:07 ` Mel Gorman
2010-01-06 16:26 ` [PATCH 5/7] Add /proc trigger for memory compaction Mel Gorman
2010-01-07 22:00 ` David Rientjes
2010-01-13 23:23 ` David Rientjes
2010-01-20 9:48 ` Mel Gorman
2010-01-20 9:48 ` Mel Gorman
2010-01-20 18:12 ` Christoph Lameter
2010-01-20 20:53 ` Mel Gorman
2010-01-20 20:48 ` David Rientjes [this message]
2010-01-21 14:09 ` Mel Gorman
2010-01-21 23:34 ` David Rientjes
2010-01-06 16:26 ` [PATCH 6/7] Direct compact when a high-order allocation fails Mel Gorman
2010-01-06 16:26 ` [PATCH 7/7] Do not compact within a preferred zone after a compaction failure Mel Gorman
2010-01-13 23:28 ` David Rientjes
2010-01-20 9:51 ` Mel Gorman
2010-01-21 3:12 ` [RFC-PATCH 0/7] Memory Compaction v1 KOSAKI Motohiro
2010-01-21 10:11 ` Mel Gorman
2010-01-22 0:16 ` KOSAKI Motohiro
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