Re: [PATCH v3 0/1] man/set_mempolicy.2,mbind.2: add MPOL_LOCAL NUMA memory policy documentation

From: Michael Kerrisk (man-pages)
Date: Wed Oct 12 2016 - 10:38:57 EST


Hi Christoph,

On 12 October 2016 at 16:08, Christoph Lameter <cl@xxxxxxxxx> wrote:
> On Wed, 12 Oct 2016, Michael Kerrisk (man-pages) wrote:
>
>> > +arguments must specify the empty set. If the "local node" is low
>> > +on free memory the kernel will try to allocate memory from other
>> > +nodes. The kernel will allocate memory from the "local node"
>> > +whenever memory for this node is available. If the "local node"
>> > +is not allowed by the process's current cpuset context the kernel
>> > +will try to allocate memory from other nodes. The kernel will
>> > +allocate memory from the "local node" whenever it becomes allowed
>> > +by the process's current cpuset context. In contrast
>> > +.B MPOL_DEFAULT
>> > +reverts to the policy of the process which may have been set with
>> > +.BR set_mempolicy (2).
>> > +It may not be the "local allocation".
>>
>> What is the sense of "may not be" here? (And repeated below).
>> Is the meaning "this could be something other than"?
>> Presumably the answer is yes, in which case I'll clarify
>> the wording there. Let me know.
>
> Someone may have set for example a round robin policy with numactl
> --interleave before starting the process? Then allocations will go through
> all nodes.

So the sense is then "this could be something other than", right?

Cheers,

Michael

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/