On Tue, Mar 31, 2020 at 04:21:38PM +0200, Michal Hocko wrote: > On Tue 31-03-20 22:03:32, Baoquan He wrote: > > Hi Michal, > > > > On 03/31/20 at 10:55am, Michal Hocko wrote: > > > On Tue 31-03-20 11:14:23, Mike Rapoport wrote: > > > > Maybe I mis-read the code, but I don't see how this could happen. In the > > > > HAVE_MEMBLOCK_NODE_MAP=y case, free_area_init_node() calls > > > > calculate_node_totalpages() that ensures that node->node_zones are entirely > > > > within the node because this is checked in zone_spanned_pages_in_node(). > > > > > > zone_spanned_pages_in_node does chech the zone boundaries are within the > > > node boundaries. But that doesn't really tell anything about other > > > potential zones interleaving with the physical memory range. > > > zone->spanned_pages simply gives the physical range for the zone > > > including holes. Interleaving nodes are essentially a hole > > > (__absent_pages_in_range is going to skip those). > > > > > > That means that when free_area_init_core simply goes over the whole > > > physical zone range including holes and that is why we need to check > > > both for physical and logical holes (aka other nodes). > > > > > > The life would be so much easier if the whole thing would simply iterate > > > over memblocks... > > > > The memblock iterating sounds a great idea. I tried with putting the > > memblock iterating in the upper layer, memmap_init(), which is used for > > boot mem only anyway. Do you think it's doable and OK? It yes, I can > > work out a formal patch to make this simpler as you said. The draft code > > is as below. Like this it uses the existing code and involves little change. > > Doing this would be a step in the right direction! I haven't checked the > code very closely though. The below sounds way too simple to be truth I > am afraid. First for_each_mem_pfn_range is available only for > CONFIG_HAVE_MEMBLOCK_NODE_MAP (which is one of the reasons why I keep > saying that I really hate that being conditional). Also I haven't really > checked the deferred initialization path - I have a very vague > recollection that it has been converted to the memblock api but I have > happilly dropped all that memory. The Baoquan's patch almost did it, at least for simple case of qemu with 2 nodes. It's only missing the adjustment to the size passed to memmap_init_zone() as it may change because of clamping. I've drafted something that removes HAVE_MEMBLOCK_NODE_MAP and added this patch there [1]. For several memory configurations I could emulate with qemu it worked. I'm going to wait a bit to see of kbuild is happy and then I'll send the patches. Baoquan, I took liberty to add your SoB, hope you don't mind. [1] https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=memblock/all-have-node-map > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 138a56c0f48f..558d421f294b 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -6007,14 +6007,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, > > * function. They do not exist on hotplugged memory. > > */ > > if (context == MEMMAP_EARLY) { > > - if (!early_pfn_valid(pfn)) { > > - pfn = next_pfn(pfn); > > - continue; > > - } > > - if (!early_pfn_in_nid(pfn, nid)) { > > - pfn++; > > - continue; > > - } > > if (overlap_memmap_init(zone, &pfn)) > > continue; > > if (defer_init(nid, pfn, end_pfn)) > > @@ -6130,9 +6122,17 @@ static void __meminit zone_init_free_lists(struct zone *zone) > > } > > > > void __meminit __weak memmap_init(unsigned long size, int nid, > > - unsigned long zone, unsigned long start_pfn) > > + unsigned long zone, unsigned long range_start_pfn) > > { > > - memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL); > > + unsigned long start_pfn, end_pfn; > > + unsigned long range_end_pfn = range_start_pfn + size; > > + int i; > > + for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { > > + start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn); > > + end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn); > > + if (end_pfn > start_pfn) > > + memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL); > > + } > > } > > > > static int zone_batchsize(struct zone *zone) > > -- > Michal Hocko > SUSE Labs -- Sincerely yours, Mike.
