On 07/01/18 at 10:04pm, Pavel Tatashin wrote: > +/* > + * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end) > + * And number of present sections in this node is map_count. > + */ > +void __init sparse_init_nid(int nid, unsigned long pnum_begin, > + unsigned long pnum_end, > + unsigned long map_count) > +{ > + unsigned long pnum, usemap_longs, *usemap, map_index; > + struct page *map, *map_base; > + > + usemap_longs = BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS); > + usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nid), > + usemap_size() * > + map_count); > + if (!usemap) { > + pr_err("%s: usemap allocation failed", __func__); Wondering if we can provide more useful information for better debugging if failed. E.g here tell on what nid the usemap allocation failed. > + goto failed; > + } > + map_base = sparse_populate_node(pnum_begin, pnum_end, > + map_count, nid); > + map_index = 0; > + for_each_present_section_nr(pnum_begin, pnum) { > + if (pnum >= pnum_end) > + break; > + > + BUG_ON(map_index == map_count); > + map = sparse_populate_node_section(map_base, map_index, > + pnum, nid); > + if (!map) { > + pr_err("%s: memory map backing failed. Some memory will not be available.", > + __func__); And here tell nid and the memory section nr failed. > + pnum_begin = pnum; > + goto failed; > + } > + check_usemap_section_nr(nid, usemap); > + sparse_init_one_section(__nr_to_section(pnum), pnum, map, > + usemap); > + map_index++; > + usemap += usemap_longs; > + } > + return; > +failed: > + /* We failed to allocate, mark all the following pnums as not present */ > + for_each_present_section_nr(pnum_begin, pnum) { > + struct mem_section *ms; > + > + if (pnum >= pnum_end) > + break; > + ms = __nr_to_section(pnum); > + ms->section_mem_map = 0; > + } > +} > + > /* > * Allocate the accumulated non-linear sections, allocate a mem_map > * for each and record the physical to section mapping. > -- > 2.18.0 >