Hi, On Tue, Sep 18, 2012 at 05:39:37PM +0800, Wen Congyang wrote: > At 09/13/2012 01:18 AM, Vasilis Liaskovitis Wrote: > > Hi, > > > > On Wed, Sep 12, 2012 at 01:20:28PM +0800, Wen Congyang wrote: > >> Hmm, seabios doesn't support ACPI table SLIT. We can specify node it for dimm > >> device, so I think we should support SLIT in seabios. Otherwise we may meet > >> the following kernel messages: > >> [ 325.016769] init_memory_mapping: [mem 0x40000000-0x5fffffff] > >> [ 325.018060] [mem 0x40000000-0x5fffffff] page 2M > >> [ 325.019168] [ffffea0001000000-ffffea00011fffff] potential offnode page_structs > >> [ 325.024172] [ffffea0001200000-ffffea00013fffff] potential offnode page_structs > >> [ 325.028596] [ffffea0001400000-ffffea00017fffff] PMD -> [ffff880035000000-ffff8800353fffff] on node 1 > >> [ 325.031775] [ffffea0001600000-ffffea00017fffff] potential offnode page_structs > >> > >> Do you have plan to do it? > > thanks for testing. > > > > commit 5294828 from https://github.com/vliaskov/seabios/commits/memhp-v2 > > implements a SLIT table for the given numa nodes. > > Hmm, why do you set node_distance(i, j) to REMOTE_DISTANCE if i != j? What's the alternative? Afaik SLIT[i][j] shows the distance between proximity domains (_PXM) i and j. It doesn't correspond to individual SRAT entries. So i and j here are not memory ranges associated with 2 different dimms. They denote domains i and j, which map to 2 different logical nodeids in the kernel. A default setting would be to set the entry to REMOTE_DISTANCE for all different domains (i!=j). So this SLIT implementation is not useful, since it results in the same numa_distance values as the non-SLIT kernel calculation in include/linux/topology.h > > > > > However I am not sure the SLIT is the problem. The kernel builds a default > > numa_distance table in arch/x86/mm/numa.c: numa_alloc_distance(). If the BIOS > > doesn't present a SLIT, this should take effect (numactl --hardware should > > report this table) > > If the BIOS doesn't present a SLIT, numa_distance_cnt is set to 0 in the > function numa_reset_distance(). So node_distance(i, j) is REMOTE_DISTANCE(i != j). > > > > > Do you have more details on how to reproduce the warning? e.g. how many dimms > > are present in the system? Does this happen on the first dimm hot-plugged? > > Are all SRAT entries parsed correctly at boot-time or do you see any other > > warnings at boot-time? > > I can't reproduce it again. IIRC, I only do the following things: > hotplug a memory device, online the pages, offline the pages and hot remove > the memory device. Is the sparse_vmemmap allocation supposed to guarantee no off-node allocations? If not, then the warning could be valid. thanks, - Vasilis -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>