On Sun, Mar 24, 2019 at 12:18:26PM +0530, Anshuman Khandual wrote: > Hello Oscar, Hi Anshuman, > Passing down node ID till unregister_mem_sect_under_nodes() solves the problem of > querying struct page for nid but the current code assumes that the pfn range for > any given memory section can have different node IDs. Hence it scans over the > section and try to remove all possible node <---> memory block sysfs links. > > I am just wondering is that assumption even correct ? Can we really have a memory > section which belongs to different nodes ? Is that even possible. Yes, current code assumes that, but looking at when we init sections at boot stage, it seems like a 1:1 map to me. E.g, in memory_present(), we do encode the nid in section's section_mem_map field to use that later on in sparse_init(), and get the node we should allocate the data structures from. And in memory_present() itself, in case we do not use page's flags field, we end up using the section_to_node_table[] table, which is clearly a 1:1 map. So, I might be wrong here, but I think that we do not really have nodes mixed in a section. -- Oscar Salvador SUSE L3
