LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: David Rientjes <rientjes@google.com>
To: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	Andi Kleen <ak@suse.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [patch 5/6] mempolicy: add MPOL_F_RELATIVE_NODES flag
Date: Tue, 26 Feb 2008 17:17:05 -0800 (PST)	[thread overview]
Message-ID: <alpine.DEB.1.00.0802261704310.25919@chino.kir.corp.google.com> (raw)
In-Reply-To: <alpine.DEB.1.00.0802250016120.12368@chino.kir.corp.google.com>

On Mon, 25 Feb 2008, David Rientjes wrote:

> Adds another optional mode flag, MPOL_F_RELATIVE_NODES, that specifies
> nodemasks passed via set_mempolicy() or mbind() should be considered
> relative to the current task's mems_allowed.
> 

Here's some examples of the functional changes between the default 
actions of the various mempolicy modes and the new behavior with 
MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES.

To read this, the logical order follows from the left-most column to the 
right-most:

 - "mems" is the task's mems_allowed as constrained by its attached
   cpuset,

 - "nodemask" is the mask passed with the set_mempolicy() or mbind() call 
   for that particular policy,

 - the first "result" is the nodemask that the policy is effected over,

 - "rebind" is the nodemask of a subsequent change to the cpuset's mems,
   and

 - the second "result" is the nodemask that the policy is now effected 
   over.

			MPOL_INTERLEAVE
			---------------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-2[*]		4-6		4-5
	1-3	1-2		1-2		0-2		0-1
	1-3	1-3		1-3		4-7		4-6
	1-3	2-4		2-3		0-2		1-2
	1-3	2-6		2-3		4-7		5-6
	1-3	4-7		EINVAL
	1-3	0-7		1-3		4-7		4-6

			MPOL_PREFERRED
			--------------
	mems	nodemask	result		rebind		result
	1-3	0		EINVAL
	1-3	2		2		4-7		5
	1-3	5		EINVAL

			MPOL_BIND
			---------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-2		0-2		0-1
	1-3	1-2		1-2		2-7		2-3
	1-3	1-3		1-3		0-1		0-1
	1-3	2-4		2-3		3-6		4-5
	1-3	2-6		2-3		5		5
	1-3	4-7		EINVAL
	1-3	0-7		1-3		1-3		1-3

 [*] Notice how the resulting nodemask for all of these examples when
     creating the mempolicy is intersected with mems_allowed.  This is
     the current behavior, with contextualize_policy(), and is identical
     to the initial result of the MPOL_F_STATIC_NODES case.

     Perhaps it would make more sense to remap the nodemask when it is
     created, as well, in the ~MPOL_F_STATIC_NODES case.  For example, in
     this case, the "result" would be 1-3 instead.

     That is a departure from what is currently implemented in HEAD (and,
     thus, can be used as ample justification for the above behavior) but
     makes more sense.  Thoughts?

			MPOL_INTERLEAVE | MPOL_F_STATIC_NODES
			-------------------------------------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-2		4-6		nil
	1-3	1-2		1-2		0-2		1-2
	1-3	1-3		1-3		4-7		nil
	1-3	2-4		2-3		0-2		2
	1-3	2-6		2-3		4-7		4-6
	1-3	4-7		EINVAL
	1-3	0-7		1-3		4-7		4-7

			MPOL_PREFERRED | MPOL_F_STATIC_NODES
			------------------------------------
	mems	nodemask	result		rebind		result
	1-3	0		EINVAL
	1-3	2		2		4-7		-1[**]
	1-3	5		EINVAL

 [**] Upon further rebind with a nodemask of 2, the preferred node would
      again be 2.

			MPOL_BIND | MPOL_F_STATIC_NODES
			-------------------------------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-2		0-2		0-2
	1-3	1-2		1-2		2-7		2
	1-3	1-3		1-3		0-1		1
	1-3	2-4		2-3		3-6		3-4
	1-3	2-6		2-3		5		5
	1-3	4-7		EINVAL
	1-3	0-7		1-3		1-3		1-3

			MPOL_INTERLEAVE | MPOL_F_RELATIVE_NODES
			---------------------------------------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-3		4-6		4-6
	1-3	1-2		2-3		0-2		1-2
	1-3	1-3		1-3		4-7		5-7
	1-3	2-4		1-3		0-2		0-2
	1-3	2-6		1-3		4-7		4-7
	1-3	4-7		1-3		0-1,5		0-1,5
	1-3	0-7		1-3		4-7		4-7

			MPOL_PREFERRED | MPOL_F_RELATIVE_NODES
			--------------------------------------
	mems	nodemask	result		rebind		result[***]
	1-3	0		1		0		1
	1-3	2		3		4-7		3
	1-3	5		3		0-7		3

 [***] All of these results are wrong and will be corrected in the next
       posting of the patchset.  They change the preferred node in some
       cases to be a node that is expressly excluded from being accessed
       by the cpuset mems change.

			MPOL_BIND | MPOL_F_RELATIVE_NODES
			---------------------------------
	mems	nodemask	result		rebind		result
	1-3	0-2		1-3		0-2		0-2
	1-3	1-2		2-3		2-7		3-4
	1-3	1-3		1-3		0-1		0-1
	1-3	2-4		1-3		3-6		3,5-6
	1-3	2-6		1-3		5		5
	1-3	4-7		1-3		0-3,6		0-2,6
	1-3	0-7		1-3		1-3		1-3

  parent reply	other threads:[~2008-02-27  1:17 UTC|newest]

Thread overview: 36+ 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
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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.1.00.0802261704310.25919@chino.kir.corp.google.com \
    --to=rientjes@google.com \
    --cc=Lee.Schermerhorn@hp.com \
    --cc=ak@suse.de \
    --cc=clameter@sgi.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pj@sgi.com \
    --subject='Re: [patch 5/6] mempolicy: add MPOL_F_RELATIVE_NODES flag' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).