CPU to node mapping is set via the following sequence:

 1. numa_init_array(): Set up roundrobin from cpu to online node

 2. init_cpu_to_node(): Set that according to apicid_to_node[]
			according to srat only handle the node that
			is online, and leave other cpu on node
			without ram (aka not online) to still
			roundrobin.

3. later call srat_detect_node for Intel/AMD, will use first_online
   node or nearby node.

Problem is that setup_per_cpu_areas() is not called between 2 and 3,
the per_cpu for cpu on node with ram is on different node, and could
put that on node with two hops away.

So try to optimize this and add find_near_online_node() and call
init_cpu_to_node().
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B07A739.3030104@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In the NUMA bootmem setup failure path we freed nodedata_phys
incorrectly.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B07A739.3030104@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add interleaved NUMA emulation support

This patch interleaves emulated nodes over the system's physical
nodes. This is required for interleave optimizations since
mempolicies, for example, operate by iterating over a nodemask and
act without knowledge of node distances.  It can also be used for
testing memory latencies and NUMA bugs in the kernel.

There're a couple of ways to do this:

 - divide the number of emulated nodes by the number of physical
   nodes and allocate the result on each physical node, or

 - allocate each successive emulated node on a different physical
   node until all memory is exhausted.

The disadvantage of the first option is, depending on the asymmetry
in node capacities of each physical node, emulated nodes may
substantially differ in size on a particular physical node compared
to another.

The disadvantage of the second option is, also depending on the
asymmetry in node capacities of each physical node, there may be
more emulated nodes allocated on a single physical node as another.

This patch implements the second option; we sacrifice the
possibility that we may have slightly more emulated nodes on a
particular physical node compared to another in lieu of node size
asymmetry.

 [ Note that "node capacity" of a physical node is not only a
   function of its addressable range, but also is affected by
   subtracting out the amount of reserved memory over that range.
   NUMA emulation only deals with available, non-reserved memory
   quantities. ]

We ensure there is at least a minimal amount of available memory
allocated to each node.  We also make sure that at least this
amount of available memory is available in ZONE_DMA32 for any node
that includes both ZONE_DMA32 and ZONE_NORMAL.

This patch also cleans the emulation code up by no longer passing
the statically allocated struct bootnode array among the various
functions. This init.data array is not allocated on the stack since
it may be very large and thus it may be accessed at file scope.

The WARN_ON() for nodes_cover_memory() when faking proximity
domains is removed since it relies on successive nodes always
having greater start addresses than previous nodes; with
interleaving this is no longer always true.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Ankita Garg <ankita@in.ibm.com>
Cc: Len Brown <len.brown@intel.com>
LKML-Reference: <alpine.DEB.1.00.0909251519150.14754@chino.kir.corp.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This is the counterpart to "x86: export k8 physical topology" for
SRAT. It is not as invasive because the acpi code already seperates
node setup into detection and registration steps, with the
exception of registering e820 active regions in
acpi_numa_memory_affinity_init().  This is now moved to
acpi_scan_nodes() if NUMA emulation is disabled or deferred.

acpi_numa_init() now returns a value which specifies whether an
underlying SRAT was located.  If so, that topology can be used by
the emulation code to interleave emulated nodes over physical nodes
or to register the nodes for ACPI.

acpi_get_nodes() may now be used to export the srat physical
topology of the machine for NUMA emulation.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Ankita Garg <ankita@in.ibm.com>
Cc: Len Brown <len.brown@intel.com>
LKML-Reference: <alpine.DEB.1.00.0909251518580.14754@chino.kir.corp.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

To eventually interleave emulated nodes over physical nodes, we
need to know the physical topology of the machine without actually
registering it.  This does the k8 node setup in two parts:
detection and registration.  NUMA emulation can then used the
physical topology detected to setup the address ranges of emulated
nodes accordingly.  If emulation isn't used, the k8 nodes are
registered as normal.

Two formals are added to the x86 NUMA setup functions: `acpi' and
`k8'. These represent whether ACPI or K8 NUMA has been detected;
both cannot be true at the same time.  This specifies to the NUMA
emulation code whether an underlying physical NUMA topology exists
and which interface to use.

This patch deals solely with separating the k8 setup path into
Northbridge detection and registration steps and leaves the ACPI
changes for a subsequent patch.  The `acpi' formal is added here,
however, to avoid touching all the header files again in the next
patch.

This approach also ensures emulated nodes will not span physical
nodes so the true memory latency is not misrepresented.

k8_get_nodes() may now be used to export the k8 physical topology
of the machine for NUMA emulation.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Ankita Garg <ankita@in.ibm.com>
Cc: Len Brown <len.brown@intel.com>
LKML-Reference: <alpine.DEB.1.00.0909251518400.14754@chino.kir.corp.google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Recently there were some changes to the meaning of node_possible_map,
and it is quite strange:

- the node without memory would be set in node_possible_map
- but some node with less NODE_MIN_SIZE will be kicked out of node_possible_map.

fix it by adding strict_setup_node_bootmem().

Also, remove unparse_node().

so result will be:

1. cpu_to_node() will return online node only (nearest one)
2. apicid_to_node() still returns the node that could be not online but is set
   in node_possible_map.
3. node_possible_map will include nodes that mem on it are less NODE_MIN_SIZE

v2: after move_cpus_to_node change.

[ Impact: get node_possible_map right ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Tested-by: NJack Steiner <steiner@sgi.com>
LKML-Reference: <4A0C49BE.6080800@kernel.org>
[ v3: various small cleanups and comment clarifications ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

after:

 | commit b263295d
 | Author: Christoph Lameter <clameter@sgi.com>
 | Date:   Wed Jan 30 13:30:47 2008 +0100
 |
 |    x86: 64-bit, make sparsemem vmemmap the only memory model

we don't have MEMORY_HOTPLUG_RESERVE anymore.

Historically, x86-64 had an architecture-specific method for memory hotplug
whereby it scanned the SRAT for physical memory ranges that could be
potentially used for memory hot-add later. By reserving those ranges
without physical memory, the memmap would be allocated and left dormant
until needed. This depended on the DISCONTIG memory model which has been
removed so the code implementing HOTPLUG_RESERVE is now dead.

This patch removes the dead code used by MEMORY_HOTPLUG_RESERVE.

(Changelog authored by Mel.)

v2: updated changelog, and remove hotadd= in doc

[ Impact: remove dead code ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Reviewed-by: NMel Gorman <mel@csn.ul.ie>
Workflow-found-OK-by: NAndrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A0C4910.7090508@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

64-bit UMA and NUMA versions of paging_init() are almost identical.
Therefore, merge the copy in mm/numa_64.c to mm/init_64.c to remove
duplicate code.

[ Impact: cleanup ]
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1241699741.17846.30.camel@penberg-laptop>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit dc098551 ("x86/uv: fix init of memory-less nodes") causes a
two sockets system (where node-1 doesn't have RAM installed) to crash.

That commit makes node_possible include cpu nodes that do not have memory.
So check boundary in setup_node_bootmem().

[ Impact: fix boot crash on RAM-less NUMA node system ]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
LKML-Reference: <49EF89DF.9090404@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

We are removing cpumask_t in favour of struct cpumask: mainly as a
marker of what code is now CONFIG_CPUMASK_OFFSTACK-safe.

The only non-trivial change here is vector_allocation_domain():
explicitly clear the mask and set the first word, rather than using
assignment.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Impact: reduce kernel memory usage when CONFIG_CPUMASK_OFFSTACK=y

Straightforward conversion: done for 32 and 64 bit kernels.
node_to_cpumask_map is now a cpumask_var_t array.

64-bit used to be a dynamic cpumask_t array, and 32-bit used to be a
static cpumask_t array.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Impact: cleanup

We take the 64-bit code and use it on 32-bit as well.  The new file
is called mm/numa.c.

In a minor cleanup, we use cpu_none_mask instead of declaring a local
cpu_mask_none.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Impact: cleanup
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

What's happening is that the assertion in mm/page_alloc.c:move_freepages()
is triggering:

	BUG_ON(page_zone(start_page) != page_zone(end_page));

Once I knew this is what was happening, I added some annotations:

	if (unlikely(page_zone(start_page) != page_zone(end_page))) {
		printk(KERN_ERR "move_freepages: Bogus zones: "
		       "start_page[%p] end_page[%p] zone[%p]\n",
		       start_page, end_page, zone);
		printk(KERN_ERR "move_freepages: "
		       "start_zone[%p] end_zone[%p]\n",
		       page_zone(start_page), page_zone(end_page));
		printk(KERN_ERR "move_freepages: "
		       "start_pfn[0x%lx] end_pfn[0x%lx]\n",
		       page_to_pfn(start_page), page_to_pfn(end_page));
		printk(KERN_ERR "move_freepages: "
		       "start_nid[%d] end_nid[%d]\n",
		       page_to_nid(start_page), page_to_nid(end_page));
 ...

And here's what I got:

	move_freepages: Bogus zones: start_page[2207d0000] end_page[2207dffc0] zone[fffff8103effcb00]
	move_freepages: start_zone[fffff8103effcb00] end_zone[fffff8003fffeb00]
	move_freepages: start_pfn[0x81f600] end_pfn[0x81f7ff]
	move_freepages: start_nid[1] end_nid[0]

My memory layout on this box is:

[    0.000000] Zone PFN ranges:
[    0.000000]   Normal   0x00000000 -> 0x0081ff5d
[    0.000000] Movable zone start PFN for each node
[    0.000000] early_node_map[8] active PFN ranges
[    0.000000]     0: 0x00000000 -> 0x00020000
[    0.000000]     1: 0x00800000 -> 0x0081f7ff
[    0.000000]     1: 0x0081f800 -> 0x0081fe50
[    0.000000]     1: 0x0081fed1 -> 0x0081fed8
[    0.000000]     1: 0x0081feda -> 0x0081fedb
[    0.000000]     1: 0x0081fedd -> 0x0081fee5
[    0.000000]     1: 0x0081fee7 -> 0x0081ff51
[    0.000000]     1: 0x0081ff59 -> 0x0081ff5d

So it's a block move in that 0x81f600-->0x81f7ff region which triggers
the problem.

This patch:

Declaration of early_pfn_to_nid() is scattered over per-arch include
files, and it seems it's complicated to know when the declaration is used.
 I think it makes fix-for-memmap-init not easy.

This patch moves all declaration to include/linux/mm.h

After this,
  if !CONFIG_NODES_POPULATES_NODE_MAP && !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
     -> Use static definition in include/linux/mm.h
  else if !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
     -> Use generic definition in mm/page_alloc.c
  else
     -> per-arch back end function will be called.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: NDavid Miller <davem@davemlloft.net>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: bug fix

Don't use per_cpu_offset() to determine if it valid to access a
per-cpu variable for a given cpu number.  It is not a valid assumption
on x86-64 anymore. Use cpu_possible() instead.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: Code movement, no functional change.

Move the 64-bit NUMA code from setup_percpu.c to numa_64.c
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Impact: cleanup, futureproof

In fact, all cpumask ops will only be valid (in general) for bit
numbers < nr_cpu_ids.  So use that instead of NR_CPUS in various
places.

This is always safe: no cpu number can be >= nr_cpu_ids, and
nr_cpu_ids is initialized to NR_CPUS at boot.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMike Travis <travis@sgi.com>
Acked-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

There are a lot of places that define either a single bootmem descriptor or an
array of them.  Use only one central array with MAX_NUMNODES items instead.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are a couple of places where (P)Dprintk is used which is an old
compile time enabled printk wrapper. Convert it to the generic
pr_debug().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

and use max_pfn directly.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

sparse mutters:
arch/x86/mm/numa_64.c:195:27: warning: symbol 'end_pfn' shadows an earlier one
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

plat_node_bdata, cmdline, nodemap_addr, nodemap_size are local to
numa_64.c. Make them static
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

  * Consolidate node_to_cpumask operations and remove the 256k
    byte node_to_cpumask_map.  This is done by allocating the
    node_to_cpumask_map array after the number of possible nodes
    (nr_node_ids) is known.

  * Debug printouts when CONFIG_DEBUG_PER_CPU_MAPS is active have
    been increased.  It now shows faults when calling node_to_cpumask()
    and node_to_cpumask_ptr().

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

  * Introduce a new PER_CPU macro called "EARLY_PER_CPU".  This is
    used by some per_cpu variables that are initialized and accessed
    before there are per_cpu areas allocated.

    ["Early" in respect to per_cpu variables is "earlier than the per_cpu
    areas have been setup".]

    This patchset adds these new macros:

	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)
	EXPORT_EARLY_PER_CPU_SYMBOL(_name)
	DECLARE_EARLY_PER_CPU(_type, _name)

	early_per_cpu_ptr(_name)
	early_per_cpu_map(_name, _idx)
	early_per_cpu(_name, _cpu)

    The DEFINE macro defines the per_cpu variable as well as the early
    map and pointer.  It also initializes the per_cpu variable and map
    elements to "_initvalue".  The early_* macros provide access to
    the initial map (usually setup during system init) and the early
    pointer.  This pointer is initialized to point to the early map
    but is then NULL'ed when the actual per_cpu areas are setup.  After
    that the per_cpu variable is the correct access to the variable.

    The early_per_cpu() macro is not very efficient but does show how to
    access the variable if you have a function that can be called both
    "early" and "late".  It tests the early ptr to be NULL, and if not
    then it's still valid.  Otherwise, the per_cpu variable is used
    instead:

	#define early_per_cpu(_name, _cpu) 			\
		(early_per_cpu_ptr(_name) ?			\
			early_per_cpu_ptr(_name)[_cpu] :	\
			per_cpu(_name, _cpu))

    A better method is to actually check the pointer manually.  In the
    case below, numa_set_node can be called both "early" and "late":

	void __cpuinit numa_set_node(int cpu, int node)
	{
	    int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);

	    if (cpu_to_node_map)
		    cpu_to_node_map[cpu] = node;
	    else
		    per_cpu(x86_cpu_to_node_map, cpu) = node;
	}

  * Add a flag "arch_provides_topology_pointers" that indicates pointers
    to topology cpumask_t maps are available.  Otherwise, use the function
    returning the cpumask_t value.  This is useful if cpumask_t set size
    is very large to avoid copying data on to/off of the stack.

  * The coverage of CONFIG_DEBUG_PER_CPU_MAPS has been increased while
    the non-debug case has been optimized a bit.

  * Remove an unreferenced compiler warning in drivers/base/topology.c

  * Clean up #ifdef in setup.c

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Remove three extern declarations for routines
that don't exist.  Fix a typo in a comment.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

typical case: four sockets system, every node has 4g ram, and we are using:

	memmap=10g$4g

to mask out memory on node1 and node2

when numa is enabled, early_node_mem is used to get node_data and node_bootmap.

if it can not get memory from the same node with find_e820_area(), it will
use alloc_bootmem to get buff from previous nodes.

so check it and print out some info about it.

need to move early_res_to_bootmem into every setup_node_bootmem.
and it takes range that node has. otherwise alloc_bootmem could return addr
that reserved early.

depends on "mm: make reserve_bootmem can crossed the nodes".
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

  * Move large array "struct bootnode nodes" from stack to _initdata
    section to reduce amount of stack space required.

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For example, If the physical address layout on a two node system with 8 GB
memory is something like:
node 0: 0-2GB, 4-6GB
node 1: 2-4GB, 6-8GB

Current kernels fail to boot/detect this NUMA topology.

ACPI SRAT tables can expose such a topology which needs to be supported.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Cleanup references to the early cpu maps for the non-SMP configuration
and remove some functions called for SMP configurations only.

Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

so use nodedata_phys directly.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

resolve boot problem reported by Mel Gorman:

   http://lkml.org/lkml/2008/2/13/404

init_cpu_to_node will use cpu->apic (from MADT or mptable) and
apic->node(from SRAT or AMD config space with k8_bus_64.c) to have
cpu->node mapping, and later identify_cpu will overwrite them
again...(with nearby_node...)

this patch checks if the node is online, otherwise it will not
update cpu_node map. so keep cpu_node map to online node before
identify_cpu..., to prevent possible error.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NThomas Gleixner <tglx@linutronix.de>

One system doesn't have RAM for node0 installed.

SRAT: PXM 0 -> APIC 0 -> Node 0
SRAT: PXM 0 -> APIC 1 -> Node 0
SRAT: PXM 1 -> APIC 2 -> Node 1
SRAT: PXM 1 -> APIC 3 -> Node 1
SRAT: Node 1 PXM 1 0-a0000
SRAT: Node 1 PXM 1 0-dd000000
SRAT: Node 1 PXM 1 0-123000000
ACPI: SLIT: nodes = 2
 10 13
 13 10
mapped APIC to ffffffffff5fb000 (        fee00000)
Bootmem setup node 1 0000000000000000-0000000123000000
  NODE_DATA [000000000000e000 - 0000000000014fff]
  bootmap [0000000000015000 -  00000000000395ff] pages 25
Could not find start_pfn for node 0
Pid: 0, comm: swapper Not tainted 2.6.24-smp-g5a514e21-dirty #14

Call Trace:
 [<ffffffff80bab498>] free_area_init_node+0x22/0x381
 [<ffffffff8045ffc5>] generic_swap+0x0/0x17
 [<ffffffff80bab0cc>] find_zone_movable_pfns_for_nodes+0x54/0x271
 [<ffffffff80baba5f>] free_area_init_nodes+0x239/0x287
 [<ffffffff80ba6311>] paging_init+0x46/0x4c
 [<ffffffff80b9dda5>] setup_arch+0x3c3/0x44e
 [<ffffffff80b978be>] start_kernel+0x6f/0x2c7
 [<ffffffff80b971cc>] _sinittext+0x1cc/0x1d3

This happens because node 0 is not online, but the node state in
mm/page_alloc.c has node 0 set.

        nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
                [N_POSSIBLE] = NODE_MASK_ALL,
                [N_ONLINE] = { { [0] = 1UL } },

So we need to clear node_online_map before initializing the memory.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patchset adds a flags variable to reserve_bootmem() and uses the
BOOTMEM_EXCLUSIVE flag in crashkernel reservation code to detect collisions
between crashkernel area and already used memory.

This patch:

Change the reserve_bootmem() function to accept a new flag BOOTMEM_EXCLUSIVE.
If that flag is set, the function returns with -EBUSY if the memory already
has been reserved in the past.  This is to avoid conflicts.

Because that code runs before SMP initialisation, there's no race condition
inside reserve_bootmem_core().

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: NBernhard Walle <bwalle@suse.de>
Cc: <linux-arch@vger.kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

print out node_data addr and bootmap_start addr.

helpful for debugging early crashes on high-end NUMA systems.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

boot oopses when a system has 64 or 128 GB of RAM installed:

Calling initcall 0xffffffff80bc33b6: sctp_init+0x0/0x711()
BUG: unable to handle kernel NULL pointer dereference at 000000000000005f
IP: [<ffffffff802bfe55>] proc_register+0xe7/0x10f
PGD 0
Oops: 0000 [1] SMP
CPU 0
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.24-smp-g5a514e21-dirty #6
RIP: 0010:[<ffffffff802bfe55>]  [<ffffffff802bfe55>] proc_register+0xe7/0x10f
RSP: 0000:ffff810824c57e60  EFLAGS: 00010246
RAX: 000000000000d7d7 RBX: ffff811024c5fa80 RCX: ffff810824c57e08
RDX: 0000000000000000 RSI: 0000000000000195 RDI: ffffffff80cc2460
RBP: ffffffffffffffff R08: 0000000000000000 R09: ffff811024c5fa80
R10: 0000000000000000 R11: 0000000000000002 R12: ffff810824c57e6c
R13: 0000000000000000 R14: ffff810824c57ee0 R15: 00000006abd25bee
FS:  0000000000000000(0000) GS:ffffffff80b4d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 000000000000005f CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 1, threadinfo ffff810824c56000, task ffff812024c52000)
Stack:  ffffffff80a57348 0000019500000000 ffff811024c5fa80 0000000000000000
 00000000ffffff97 ffffffff802bfef0 0000000000000000 ffffffffffffffff
 0000000000000000 ffffffff80bc3b4b ffff810824c57ee0 ffffffff80bc34a5
Call Trace:
 [<ffffffff802bfef0>] ? create_proc_entry+0x73/0x8a
 [<ffffffff80bc3b4b>] ? sctp_snmp_proc_init+0x1c/0x34
 [<ffffffff80bc34a5>] ? sctp_init+0xef/0x711
 [<ffffffff80b976e3>] ? kernel_init+0x175/0x2e1
 [<ffffffff8020ccf8>] ? child_rip+0xa/0x12
 [<ffffffff80b9756e>] ? kernel_init+0x0/0x2e1
 [<ffffffff8020ccee>] ? child_rip+0x0/0x12

Code: 1e 48 83 7b 38 00 75 08 48 c7 43 38 f0 e8 82 80 48 83 7b 30 00 75 08 48 c7 43 30 d0 e9 82 80 48 c7 c7 60 24 cc 80 e8 bd 5a 54 00 <48> 8b 45 60 48 89 6b 58 48 89 5d 60 48 89 43 50 fe 05 f5 25 a0
RIP  [<ffffffff802bfe55>] proc_register+0xe7/0x10f
 RSP <ffff810824c57e60>
CR2: 000000000000005f
---[ end trace 02c2d78def82877a ]---
Kernel panic - not syncing: Attempted to kill init!

it turns out some variables near end of bss are corrupted already.

in System.map we have
ffffffff80d40420 b rsi_table
ffffffff80d40620 B krb5_seq_lock
ffffffff80d40628 b i.20437
ffffffff80d40630 b xprt_rdma_inline_write_padding
ffffffff80d40638 b sunrpc_table_header
ffffffff80d40640 b zero
ffffffff80d40644 b min_memreg
ffffffff80d40648 b rpcrdma_tk_lock_g
ffffffff80d40650 B sctp_assocs_id_lock
ffffffff80d40658 B proc_net_sctp
ffffffff80d40660 B sctp_assocs_id
ffffffff80d40680 B sysctl_sctp_mem
ffffffff80d40690 B sysctl_sctp_rmem
ffffffff80d406a0 B sysctl_sctp_wmem
ffffffff80d406b0 b sctp_ctl_socket
ffffffff80d406b8 b sctp_pf_inet6_specific
ffffffff80d406c0 b sctp_pf_inet_specific
ffffffff80d406c8 b sctp_af_v4_specific
ffffffff80d406d0 b sctp_af_v6_specific
ffffffff80d406d8 b sctp_rand.33270
ffffffff80d406dc b sctp_memory_pressure
ffffffff80d406e0 b sctp_sockets_allocated
ffffffff80d406e4 b sctp_memory_allocated
ffffffff80d406e8 b sctp_sysctl_header
ffffffff80d406f0 b zero
ffffffff80d406f4 A __bss_stop
ffffffff80d406f4 A _end

and setup_node_bootmem() will use that page 0xd40000 for bootmap
Bootmem setup node 0 0000000000000000-0000000828000000
  NODE_DATA [000000000008a485 - 0000000000091484]
  bootmap [0000000000d406f4 -  0000000000e456f3] pages 105
Bootmem setup node 1 0000000828000000-0000001028000000
  NODE_DATA [0000000828000000 - 0000000828006fff]
  bootmap [0000000828007000 -  0000000828106fff] pages 100
Bootmem setup node 2 0000001028000000-0000001828000000
  NODE_DATA [0000001028000000 - 0000001028006fff]
  bootmap [0000001028007000 -  0000001028106fff] pages 100
Bootmem setup node 3 0000001828000000-0000002028000000
  NODE_DATA [0000001828000000 - 0000001828006fff]
  bootmap [0000001828007000 -  0000001828106fff] pages 100

setup_node_bootmem() makes NODE_DATA cacheline aligned,
and bootmap is page-aligned.

the patch updates find_e820_area() to make sure we can meet
the alignment constraints.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

helps debugging problems in this rather murky area of code.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>