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From: Christoph Lameter <cl@linux.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, Pekka Enberg <penberg@cs.helsinki.fi>,
	akpm@linux-foundation.org, Mel Gorman <mel@skynet.ie>,
	andi@firstfloor.org, Rik van Riel <riel@redhat.com>,
	Dave Chinner <dchinner@redhat.com>,
	Christoph Hellwig <hch@lst.de>
Subject: [RFC 0/8] Xarray object migration V1
Date: Wed, 27 Dec 2017 16:06:36 -0600	[thread overview]
Message-ID: <20171227220636.361857279@linux.com> (raw)

This is a patchset on top of Matthew Wilcox Xarray code and implements
object migration of xarray nodes. The migration is integrated into
the defragmetation and shrinking logic of the slab allocator.

Defragmentation will ensure that all xarray slab pages have
less objects available than specified by the slab defrag ratio.

Slab shrinking will create a slab cache with optimal object
density. Only one slab page will have available objects per node.

To test apply this patchset on top of Matthew Wilcox Xarray code
from Dec 11th (See infradead github).

Then go to

/sys/kernel/slab/radix_tree

Inspect the number of partial slab pages

	cat partial

And then perform a cache shrink operation

	echo 1 >shrink


This is just a barebones approach using a special mode
of the slab migration patchset that does not require refcounts.

If this is acceptable then additional functionality can be added:

1. Migration of objects to a specific node

2. Dispersion of objects across all nodes (MPOL_INTERLEAVE)

3. Subsystems can request to move an object to a specific node.

4. Tying into the page migration and page defragmentation logic so
   that so far unmovable pages that are in the way of creating a
   contiguous block of memory will become movable.

This is only possible for xarray for now but it would be worthwhile
to extend this to dentries and inodes.
 

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             reply	other threads:[~2017-12-27 22:06 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-27 22:06 Christoph Lameter [this message]
2017-12-27 22:06 ` [RFC 2/8] slub: Add defrag_ratio field and sysfs support Christoph Lameter
2017-12-30  6:20   ` Matthew Wilcox
2018-01-02 14:53     ` Christopher Lameter
2017-12-27 22:06 ` [RFC 3/8] slub: Add isolate() and migrate() methods Christoph Lameter
2017-12-30  6:42   ` Matthew Wilcox
2018-01-01 21:20     ` Matthew Wilcox
2018-01-02 14:56       ` Christopher Lameter
2018-01-02 14:55     ` Christopher Lameter
2017-12-27 22:06 ` [RFC 4/8] slub: Sort slab cache list and establish maximum objects for defrag slabs Christoph Lameter
2017-12-27 22:06 ` [RFC 5/8] slub: Slab defrag core Christoph Lameter
2017-12-27 22:06 ` [RFC 6/8] slub: Extend slabinfo to support -D and -F options Christoph Lameter
2017-12-27 22:06 ` [RFC 7/8] xarray: Implement migration function for objects Christoph Lameter
2017-12-27 22:06 ` [RFC 8/8] Add debugging output Christoph Lameter
2017-12-28  5:19 ` [RFC 0/8] Xarray object migration V1 Randy Dunlap
2017-12-28 14:57   ` Christopher Lameter
2017-12-28 17:18     ` James Bottomley
2017-12-28 17:33       ` Benjamin LaHaise
2017-12-28 17:40         ` James Bottomley
2017-12-28 19:17           ` Benjamin LaHaise
2017-12-28 20:00             ` James Bottomley
2017-12-28 20:33               ` Benjamin LaHaise
2017-12-28 22:24 ` Dave Chinner
2017-12-29  0:19   ` Christopher Lameter

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