On 2015/8/22 4:53, Rik van Riel wrote:
> 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);
>
Hi Rik,
Thank you for your reply. I find the reason is this patch,
and it is not backport to RedHat 7.0
8790c71a18e5d2d93532ae250bcf5eddbba729cd
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 873de7e..ae3c8f3 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2930,7 +2930,7 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
unsigned short mode = MPOL_DEFAULT;
unsigned short flags = 0;
- if (pol && pol != &default_policy) {
+ if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
mode = pol->mode;
flags = pol->flags;
}
Thanks,
Xishi Qiu
>
>
>
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