Re: [Crash-utility] One more change for crash

Badari Pulavarty wrote: Hi Dave, I am playing with "crash" on my machine with it fails with CONFIG_SPARSE_MEM. It looks like "node_mem_map" doesn't exist for SPARSE_MEM :( crash: invalid structure member offset: pglist_data_node_mem_map FILE: memory.c LINE: 10053 FUNCTION: dump_memory_nodes() [./crash] error trace: 100afe98 => 100d12f4 => 100d01cc => 10142f64 10142f64: .OFFSET_verify+140 100d01cc: .dump_memory_nodes+520 100d12f4: .node_table_init+492 100afe98: .vm_init+7948 Thanks, Badari typedef struct pglist_data { struct zone node_zones[MAX_NR_ZONES]; struct zonelist node_zonelists[GFP_ZONETYPES]; int nr_zones; #ifdef CONFIG_FLAT_NODE_MEM_MAP struct page *node_mem_map; #endif struct bootmem_data *bdata; Hmmm,, it kind of looks like the global "mem_map" array should be used in that case, but if that were true, then there could never be multiple pglist_data structures in that case? Here's what I mean -- in vm_init() there's this: if (VALID_STRUCT(pglist_data)) { vt->flags |= ZONES; if (symbol_exists("pgdat_list")) vt->flags |= NODES; And later on in dump_memory_nodes(), which gathers the memory-related information for each node, it looks at that "NODES" flag. - If the NODES flag is *not* set, then it presumes that there is just one node, and uses the global "mem_map". - If the NODES flag is set, then starting at the pgdat_list list head, it walks though each of the pglist_data structures (one per node), and then collects all of the individual node_mem_map pointers found in each node. In this hybrid case, I don't know how exactly the mem_map is found for each pglist_data node? You could quickly try not setting the vt->flags NODES bit, and seeing what happens. But I get the feeling that there's going to more to be done than that -- presuming that you can have more than one pglist_data node. In other words if the pglist_data list can have more than one node when CONFIG_FLAT_NODE_MEM_MAP is turned off, then we need to find out how to make the relationship between each sparse node and its associated mem_map array. Dave

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