On Wed 31-07-19 17:21:29, Mike Rapoport wrote: > On Wed, Jul 31, 2019 at 03:00:37PM +0200, Michal Hocko wrote: > > On Wed 31-07-19 15:26:32, Mike Rapoport wrote: > > > 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(). > > > > I am sorry, but I still do not follow. Who is consuming that node id > > information when NUMA=n. In other words why cannot we simply do > > We can, I think nobody cared to change it. It would be great if somebody with the actual HW could try it out. I can throw a patch but I do not even have a cross compiler in my toolbox. > > > diff --git a/arch/microblaze/mm/init.c b/arch/microblaze/mm/init.c > > index a015a951c8b7..3a47e8db8d1c 100644 > > --- a/arch/microblaze/mm/init.c > > +++ b/arch/microblaze/mm/init.c > > @@ -175,14 +175,9 @@ void __init setup_memory(void) > > > > start_pfn = memblock_region_memory_base_pfn(reg); > > end_pfn = memblock_region_memory_end_pfn(reg); > > - memblock_set_node(start_pfn << PAGE_SHIFT, > > - (end_pfn - start_pfn) << PAGE_SHIFT, > > - &memblock.memory, 0); > > + memory_present(0, start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT); > > memory_present() expects pfns, the shift is not needed. Right. -- Michal Hocko SUSE Labs
