On Fri 12-07-19 15:37:30, Will Deacon wrote:
Hi all,
On Fri, Jul 12, 2019 at 02:12:23PM +0200, Michal Hocko wrote:
quoted
On Fri 12-07-19 10:56:47, Hoan Tran OS wrote:
[...]
quoted
It would be good if we can enable it by-default. Otherwise, let arch
enables it by them-self. Do you have any suggestions?
I can hardly make any suggestions when it is not really clear _why_ you
want to remove this config option in the first place. Please explain
what motivated you to make this change.
Sorry, I think this confusion might actually be my fault and Hoan has just
been implementing my vague suggestion here:
https://lore.kernel.org/linux-arm-kernel/20190625101245.s4vxfosoop52gl4e@willie-the-truck/ (local)
If the preference of the mm folks is to leave CONFIG_NODES_SPAN_OTHER_NODES
as it is, then we can define it for arm64. I just find it a bit weird that
the majority of NUMA-capable architectures have to add a symbol in the arch
Kconfig file, for what appears to be a performance optimisation applicable
only to ia64, mips and sh.
At the very least we could make the thing selectable.
Hmm, I thought this was selectable. But I am obviously wrong here.
Looking more closely, it seems that this is indeed only about
__early_pfn_to_nid and as such not something that should add a config
symbol. This should have been called out in the changelog though.
Also while at it, does HAVE_MEMBLOCK_NODE_MAP fall into a similar
bucket? Do we have any NUMA architecture that doesn't enable it?
Thanks!
--
Michal Hocko
SUSE Labs