Date: Wed, 12 Oct 2016 09:08:31 -0500 (CDT)
From: Christoph Lameter <cl@linux.com>
To: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
cc: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>,
        kirill.shutemov@linux.intel.com, vbabka@suse.cz, rientjes@google.com,
        mhocko@kernel.org, mgorman@techsingularity.net,
        liangchen.linux@gmail.com, nzimmer@sgi.com, a.p.zijlstra@chello.nl,
        riel@redhat.com, lee.schermerhorn@hp.com, jmarchan@redhat.com,
        joe@perches.com, corbet@lwn.net, iamyooon@gmail.com,
        n-horiguchi@ah.jp.nec.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-man@vger.kernel.org,
        akpm@linux-foundation.org, linux-doc@vger.kernel.org,
        linux-api@vger.kernel.org
Subject: Re: [PATCH v3 0/1] man/set_mempolicy.2,mbind.2: add MPOL_LOCAL NUMA
 memory policy documentation
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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.