Lee,
Just a note to my previous response about a tweak to your text:
On Tue, Jul 29, 2008 at 11:47 PM, Lee Schermerhorn
<lee.schermerhorn@xxxxxx> wrote:
> Another attempt to rationalize description of MPOL_DEFAULT.
>
> Since ~2.6.25, the system default memory policy is "local allocation".
> MPOL_DEFAULT itself is a request to remove any non-default policy and
> "fall back" to the surrounding context. Try to say that without delving
> into implementation details.
>
> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
>
> man2/set_mempolicy.2 | 19 ++++++++++---------
> 1 files changed, 10 insertions(+), 9 deletions(-)
>
> Index: man-pages-3.05/man2/set_mempolicy.2
> ===================================================================
> --- man-pages-3.05.orig/man2/set_mempolicy.2 2008-07-29 16:49:36.000000000 -0400
> +++ man-pages-3.05/man2/set_mempolicy.2 2008-07-29 16:50:22.000000000 -0400
> @@ -99,15 +99,15 @@ A non-empty
> specifies physical node ids.
> Linux does will not remap the
> .I nodemask
> -when the task moves to a different cpuset context,
> -nor when the set of nodes allowed by the task's
> +when the process moves to a different cpuset context,
> +nor when the set of nodes allowed by the process'
> current cpuset context changes.
> .TP
> .B MPOL_F_RELATIVE_NODES
> A non-empty
> .I nodemask
> specifies node ids that are relative to the set of
> -node ids allowed by the task's current cpuset.
> +node ids allowed by the process' current cpuset.
> .PP
> .I nodemask
> points to a bit mask of node IDs that contains up to
> @@ -132,7 +132,7 @@ argument is ignored.
> Where a
> .I nodemask
> is required, it must contain at least one node that is on-line,
> -allowed by the task's current cpuset context
> +allowed by the process' current cpuset context
> [unless the
> .B MPOL_F_STATIC_NODES
> mode flag is specified],
> @@ -152,8 +152,10 @@ cpuset context includes one or more of t
>
> The
> .B MPOL_DEFAULT
> -mode is the default and means to allocate memory locally,
> -i.e., on the node of the CPU that triggered the allocation.
> +mode specifies that any non-default process memory policy be removed
> +and "fall back" to the system default policy.
I made this last line:
so that the memory policy "falls back" to the system
default policy.
Cheers,
Michael
> +The system default policy is "local allocation"--
> +i.e., allocate memory on the node of the CPU that triggered the allocation.
> .I nodemask
> must be specified as NULL.
> If the "local node" contains no free memory, the system will
> @@ -203,9 +205,8 @@ If the
> .I nodemask
> and
> .I maxnode
> -arguments specify the empty set, then the memory is allocated on
> -the node of the CPU that triggered the allocation (like
> -.BR MPOL_DEFAULT ).
> +arguments specify the empty set, then the policy specifies
> +explicit local allocation.
>
> The process memory policy is preserved across an
> .BR execve (2),
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
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