Messages in this thread | | | Subject | Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA | From | Hoan Tran <> | Date | Fri, 3 Apr 2020 09:36:10 -0700 |
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Hi,
On 4/3/20 12:09 AM, Baoquan He wrote: > On 04/02/20 at 09:46pm, Hoan Tran wrote: >> Hi All, >> >> On 3/31/20 7:31 AM, Baoquan He wrote: >>> On 03/31/20 at 04:21pm, 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. >>> >>> Thanks for your quick response and pointing out the rest suspect aspects, >>> I will investigate what you mentioned, see if they impact. >> >> I would like to check if we still move on with my patch to remove >> CONFIG_NODES_SPAN_OTHER_NODES and have another patch on top it? > > I think we would like to replace CONFIG_NODES_SPAN_OTHER_NODES with > CONFIG_NUMA, and just let UMA return 0 as node id, as Michal replied in > another mail. Anyway, your patch 2~5 are still needed to sit on top of > the change of this new plan.
Got it. Thanks for quick response.
Regards Hoan >
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