On Wed, Jul 31, 2019 at 01:40:16PM +0200, Michal Hocko wrote: > On Wed 31-07-19 14:14:22, Mike Rapoport wrote: > > On Wed, Jul 31, 2019 at 10:03:09AM +0200, Michal Hocko wrote: > > > On Wed 31-07-19 09:24:21, Mike Rapoport wrote: > > > > [ sorry for a late reply too, somehow I missed this thread before ] > > > > > > > > On Tue, Jul 30, 2019 at 10:14:15AM +0200, Michal Hocko wrote: > > > > > [Sorry for a late reply] > > > > > > > > > > On Mon 15-07-19 17:55:07, Hoan Tran OS wrote: > > > > > > Hi, > > > > > > > > > > > > On 7/12/19 10:00 PM, Michal Hocko wrote: > > > > > [...] > > > > > > > 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. > > > > > > > > > > > > Yes, do you have any other comments about my patch? > > > > > > > > > > Not really. Just make sure to explicitly state that > > > > > CONFIG_NODES_SPAN_OTHER_NODES is only about __early_pfn_to_nid and that > > > > > doesn't really deserve it's own config and can be pulled under NUMA. > > > > > > > > > > > > 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? > > > > > > > > > > > > > > > HAVE_MEMBLOCK_NODE_MAP makes huge difference in node/zone initialization > > > > sequence so it's not only about a singe function. > > > > > > The question is whether we want to have this a config option or enable > > > it unconditionally for each NUMA system. > > > > We can make it 'default NUMA', but we can't drop it completely because > > microblaze uses sparse_memory_present_with_active_regions() which is > > unavailable when HAVE_MEMBLOCK_NODE_MAP=n. > > I suppose you mean that microblaze is using > sparse_memory_present_with_active_regions even without CONFIG_NUMA, > right? Yes. > I have to confess I do not understand that code. What is the deal > with setting node id there? The sparse_memory_present_with_active_regions() iterates over memblock.memory regions and uses the node id of each region as the parameter to memory_present(). The assumption here is that sometime before each region was assigned a proper non-negative node id. microblaze uses device tree for memory enumeration and the current FDT code does memblock_add() that implicitly sets nid in memblock.memory regions to -1. So in order to have proper node id passed to memory_present() microblaze has to call memblock_set_node() before it can use sparse_memory_present_with_active_regions(). > -- > Michal Hocko > SUSE Labs -- Sincerely yours, Mike.
