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From: Paul Jackson <pj@sgi.com>
To: David Rientjes <rientjes@google.com>
Cc: akpm@linux-foundation.org, clameter@sgi.com,
	Lee.Schermerhorn@hp.com, ak@suse.de, randy.dunlap@oracle.com,
	linux-kernel@vger.kernel.org
Subject: Re: [patch 6/6] mempolicy: update NUMA memory policy documentation
Date: Tue, 26 Feb 2008 11:34:41 -0600	[thread overview]
Message-ID: <20080226113441.934c8c90.pj@sgi.com> (raw)
In-Reply-To: <alpine.DEB.1.00.0802250016380.12368@chino.kir.corp.google.com>

+	MPOL_F_RELATIVE_NODES:  This flag specifies that the nodemask passed
+	by the user should remain in the same context as it is for the
+	current task or VMA's set of accessible nodes after the memory
+	policy has been defined.
+
+	    Without this flag (and without MPOL_F_STATIC_NODES), anytime a
+	    mempolicy is rebound because of a change in the set of
+	    accessible nodes, the node (Preferred) or nodemask (Bind,
+	    Interleave) is remapped to the new set of accessible nodes.
+	    With this flag, the remap is done to ensure the context of the
+	    previous nodemask with its set of allowed mems is preserved.

Hmmm ... I've read this several times now ... still can't figure out
what it's saying ;).  And it doesn't really explain key aspects of
MPOL_F_RELATIVE_NODES, such as that it provides cpuset relative
numbering (use nodes 0..N-1, regardless of your current cpuset, to
refer to the first N nodes in whatever is your current cpuset.)

Perhaps we'd be further ahead of the game if you started with the
documentation changes to Documentation/vm/numa_memory_policy.txt,
in my patch:
	Date: Sun, 23 Dec 2007 22:24:02 -0600
	From: Paul Jackson <pj@sgi.com>
	To: David Rientjes <rientjes@google.com>
	Cc: Lee.Schermerhorn@hp.com, clameter@sgi.com
	Subject: Re: [RFC] cpuset relative memory policies - second choice
	Message-Id: <20071223222402.5486bf0a.pj@sgi.com>

Change MPOL_MASK_REL to MPOL_F_RELATIVE_NODES and similar changes.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.940.382.4214

  reply	other threads:[~2008-02-26 17:34 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-25 15:35 [patch 1/6] mempolicy: convert MPOL constants to enum David Rientjes
2008-02-25 15:35 ` [patch 2/6] mempolicy: support optional mode flags David Rientjes
2008-02-25 15:35   ` [patch 3/6] mempolicy: add MPOL_F_STATIC_NODES flag David Rientjes
2008-02-25 15:35     ` [patch 4/6] mempolicy: add bitmap_onto() and bitmap_fold() operations David Rientjes
2008-02-25 15:35       ` [patch 5/6] mempolicy: add MPOL_F_RELATIVE_NODES flag David Rientjes
2008-02-25 15:35         ` [patch 6/6] mempolicy: update NUMA memory policy documentation David Rientjes
2008-02-26 17:34           ` Paul Jackson [this message]
2008-02-26 21:23             ` David Rientjes
2008-02-26  6:12         ` [patch 5/6] mempolicy: add MPOL_F_RELATIVE_NODES flag Paul Jackson
2008-02-26  6:45           ` David Rientjes
2008-02-26 17:44         ` Paul Jackson
2008-02-26 21:17           ` David Rientjes
2008-02-26 21:30             ` Paul Jackson
2008-02-26 21:27           ` Lee Schermerhorn
2008-02-27  1:17         ` David Rientjes
2008-02-27  1:31           ` David Rientjes
2008-02-27  2:30           ` Paul Jackson
2008-02-27 15:37           ` Lee Schermerhorn
2008-02-27 17:09             ` Paul Jackson
2008-02-28 21:08             ` David Rientjes
2008-02-26  5:46     ` [patch 3/6] mempolicy: add MPOL_F_STATIC_NODES flag Paul Jackson
2008-02-26  6:53       ` David Rientjes
2008-02-26 17:56     ` Paul Jackson
2008-02-26 21:02       ` David Rientjes
2008-02-26 21:32         ` Lee Schermerhorn
2008-02-26 21:54           ` David Rientjes
2008-02-26 22:08             ` Paul Jackson
2008-02-26 21:39         ` Paul Jackson
2008-02-26  3:20 ` [patch 1/6] mempolicy: convert MPOL constants to enum Paul Jackson
2008-02-26  3:35   ` David Rientjes
2008-02-26  4:02     ` Paul Jackson
2008-02-26  4:21       ` David Rientjes
2008-02-26  4:46         ` Paul Jackson
2008-02-27 19:35 ` Christoph Lameter
2008-02-27 19:59   ` David Rientjes
2008-03-01  0:44 David Rientjes
2008-03-01  0:45 ` [patch 2/6] mempolicy: support optional mode flags David Rientjes
2008-03-01  0:45   ` [patch 3/6] mempolicy: add MPOL_F_STATIC_NODES flag David Rientjes
2008-03-01  0:45     ` [patch 4/6] mempolicy: add bitmap_onto() and bitmap_fold() operations David Rientjes
2008-03-01  0:45       ` [patch 5/6] mempolicy: add MPOL_F_RELATIVE_NODES flag David Rientjes
2008-03-01  0:45         ` [patch 6/6] mempolicy: update NUMA memory policy documentation David Rientjes
2008-03-01  0:55           ` Randy Dunlap
2008-03-01  1:14             ` David Rientjes

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