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Groups > linux.kernel > #1622561
| From | Christoph Lameter <cl@linux.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() |
| Date | 2017-04-12 23:20 +0200 |
| Message-ID | <tvxQe-1uj-13@gated-at.bofh.it> (permalink) |
| References | <tv4Ey-823-9@gated-at.bofh.it> <tv4Ey-823-17@gated-at.bofh.it> <tv7VM-1CC-13@gated-at.bofh.it> <tv9kS-2Ej-9@gated-at.bofh.it> <tvm8q-2hK-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, 12 Apr 2017, Vlastimil Babka wrote:
> >> Well, interleave_nodes() will then potentially return a node outside of
> >> the allowed memory policy when its called for the first time after
> >> mpol_rebind_.. . But thenn it will find the next node within the
> >> nodemask and work correctly for the next invocations.
> >
> > Hmm, you're right. But that could be easily fixed if il_next became il_prev, so
> > we would return the result of next_node_in(il_prev) and also store it as the new
> > il_prev, right? I somehow assumed it already worked that way.
Yup that makes sense and I thought about that when I saw the problem too.
> @@ -863,6 +856,18 @@ static int lookup_node(unsigned long addr)
> return err;
> }
>
> +/* Do dynamic interleaving for a process */
> +static unsigned interleave_nodes(struct mempolicy *policy, bool update_prev)
Why do you need an additional flag? Would it not be better to always
update and switch the update_prev=false case to simply use
next_node_in()?
> +{
> + unsigned next;
> + struct task_struct *me = current;
> +
> + next = next_node_in(me->il_prev, policy->v.nodes);
> + if (next < MAX_NUMNODES && update_prev)
> + me->il_prev = next;
> + return next;
> +}
> +
> /* Retrieve NUMA policy */
> static long do_get_mempolicy(int *policy, nodemask_t *nmask,
> unsigned long addr, unsigned long flags)
> @@ -916,7 +921,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
> *policy = err;
> } else if (pol == current->mempolicy &&
> pol->mode == MPOL_INTERLEAVE) {
> - *policy = current->il_next;
> + *policy = interleave_nodes(current->mempolicy, false);
Here
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[RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Vlastimil Babka <vbabka@suse.cz> - 2017-04-11 16:10 +0200
Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Christoph Lameter <cl@linux.com> - 2017-04-11 19:40 +0200
Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Vlastimil Babka <vbabka@suse.cz> - 2017-04-11 21:10 +0200
Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Vlastimil Babka <vbabka@suse.cz> - 2017-04-12 10:50 +0200
Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Vlastimil Babka <vbabka@suse.cz> - 2017-04-12 23:20 +0200
Re: [RFC 2/6] mm, mempolicy: stop adjusting current->il_next in mpol_rebind_nodemask() Christoph Lameter <cl@linux.com> - 2017-04-12 23:20 +0200
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