Re: is this a problem of numactl in RedHat7.0 ?

[Rik van Riel <riel@redhat.com>]

On 08/21/2015 05:27 AM, Xishi Qiu wrote:
> I use numactl(--localalloc) tool run a test case, but it shows that
> the numa policy is prefer, I don't know why.

The kernel implements MPOL_PREFERRED and MPOL_LOCAL
in the same way. Look at this code in mpol_new(),
in mm/mempolicy.c:

         /*
          * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or
          * MPOL_F_RELATIVE_NODES if the nodemask is empty (local 
allocation).
          * All other modes require a valid pointer to a non-empty nodemask.
          */
         if (mode == MPOL_PREFERRED) {
                 if (nodes_empty(*nodes)) {
                         if (((flags & MPOL_F_STATIC_NODES) ||
                              (flags & MPOL_F_RELATIVE_NODES)))
                                 return ERR_PTR(-EINVAL);
                 }
         } else if (mode == MPOL_LOCAL) {
                 if (!nodes_empty(*nodes))
                         return ERR_PTR(-EINVAL);
                 mode = MPOL_PREFERRED;
         } else if (nodes_empty(*nodes))
                 return ERR_PTR(-EINVAL);


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>