Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After adding a node into the machine, top cpuset's mems isn't updated.

By reviewing the code, we found that the update function

  cpuset_track_online_nodes()

was invoked after node_states[N_ONLINE] changes.  It is wrong because
N_ONLINE just means node has pgdat, and if node has/added memory, we use
N_HIGH_MEMORY.  So, We should invoke the update function after
node_states[N_HIGH_MEMORY] changes, just like its commit says.

This patch fixes it.  And we use notifier of memory hotplug instead of
direct calling of cpuset_track_online_nodes().
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During hotplug memory remove, memory regions should be released on a
PAGES_PER_SECTION size chunks.  This mirrors the code in add_memory where
resources are requested on a PAGES_PER_SECTION size.

Attempting to release the entire memory region fails because there is not
a single resource for the total number of pages being removed.  Instead
the resources for the pages are split in PAGES_PER_SECTION size chunks as
requested during memory add.
Signed-off-by: NNathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On large memory systems, the VM can spend way too much time scanning
through pages that it cannot (or should not) evict from memory.  Not only
does it use up CPU time, but it also provokes lock contention and can
leave large systems under memory presure in a catatonic state.

This patch series improves VM scalability by:

1) putting filesystem backed, swap backed and unevictable pages
   onto their own LRUs, so the system only scans the pages that it
   can/should evict from memory

2) switching to two handed clock replacement for the anonymous LRUs,
   so the number of pages that need to be scanned when the system
   starts swapping is bound to a reasonable number

3) keeping unevictable pages off the LRU completely, so the
   VM does not waste CPU time scanning them. ramfs, ramdisk,
   SHM_LOCKED shared memory segments and mlock()ed VMA pages
   are keept on the unevictable list.

This patch:

isolate_lru_page logically belongs to be in vmscan.c than migrate.c.

It is tough, because we don't need that function without memory migration
so there is a valid argument to have it in migrate.c.  However a
subsequent patch needs to make use of it in the core mm, so we can happily
move it to vmscan.c.

Also, make the function a little more generic by not requiring that it
adds an isolated page to a given list.  Callers can do that.

	Note that we now have '__isolate_lru_page()', that does
	something quite different, visible outside of vmscan.c
	for use with memory controller.  Methinks we need to
	rationalize these names/purposes.	--lts

[akpm@linux-foundation.org: fix mm/memory_hotplug.c build]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NLee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is nothing architecture specific about remove_memory().
remove_memory() function is common for all architectures which support
hotplug memory remove.  Instead of duplicating it in every architecture,
collapse them into arch neutral function.

[akpm@linux-foundation.org: fix the export]
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Gary Hade <garyhade@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Memory may be hot-removed on a per-memory-block basis, particularly on
POWER where the SPARSEMEM section size often matches the memory-block
size.  A user-level agent must be able to identify which sections of
memory are likely to be removable before attempting the potentially
expensive operation.  This patch adds a file called "removable" to the
memory directory in sysfs to help such an agent.  In this patch, a memory
block is considered removable if;

o It contains only MOVABLE pageblocks
o It contains only pageblocks with free pages regardless of pageblock type

On the other hand, a memory block starting with a PageReserved() page will
never be considered removable.  Without this patch, the user-agent is
forced to choose a memory block to remove randomly.

Sample output of the sysfs files:

./memory/memory0/removable: 0
./memory/memory1/removable: 0
./memory/memory2/removable: 0
./memory/memory3/removable: 0
./memory/memory4/removable: 0
./memory/memory5/removable: 0
./memory/memory6/removable: 0
./memory/memory7/removable: 1
./memory/memory8/removable: 0
./memory/memory9/removable: 0
./memory/memory10/removable: 0
./memory/memory11/removable: 0
./memory/memory12/removable: 0
./memory/memory13/removable: 0
./memory/memory14/removable: 0
./memory/memory15/removable: 0
./memory/memory16/removable: 0
./memory/memory17/removable: 1
./memory/memory18/removable: 1
./memory/memory19/removable: 1
./memory/memory20/removable: 1
./memory/memory21/removable: 1
./memory/memory22/removable: 1
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If zonelist is required to be rebuilt in online_pages(), there is no need
to recalculate vm_total_pages in that function, as it has been updated in
the call build_all_zonelists().
Signed-off-by: NKent Liu <kent.liu@linux.intel.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Change some naming
  * Magic -> types
  * MIX_INFO -> MIX_SECTION_INFO
  * Change definition of bootmem type from direct hex value

- __free_pages_bootmem() becomes __meminit.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make the needlessly global register_page_bootmem_info_section() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

free_area_init_node() gets passed in the node id as well as the node
descriptor.  This is redundant as the function can trivially get the node
descriptor itself by means of NODE_DATA() and the node's id.

I checked all the users and NODE_DATA() seems to be usable everywhere
from where this function is called.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Trying to online a new memory section that was added via memory hotplug
sometimes results in crashes when the new pages are added via __free_page.
 Reason for that is that the pageblock bitmap isn't initialized and hence
contains random stuff.  That means that get_pageblock_migratetype()
returns also random stuff and therefore

	list_add(&page->lru,
		&zone->free_area[order].free_list[migratetype]);

in __free_one_page() tries to do a list_add to something that isn't even
necessarily a list.

This happens since 86051ca5 ("mm: fix
usemap initialization") which makes sure that the pageblock bitmap gets
only initialized for pages present in a zone.  Unfortunately for hot-added
memory the zones "grow" after the memmap and the pageblock memmap have
been initialized.  Which means that the new pages have an unitialized
bitmap.  To solve this the calls to grow_zone_span() and grow_pgdat_span()
are moved to __add_zone() just before the initialization happens.

The patch also moves the two functions since __add_zone() is the only
caller and I didn't want to add a forward declaration.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a check to online_pages() to test for failure of
walk_memory_resource().  This fixes a condition where a failure
of walk_memory_resource() can lead to online_pages() returning
success without the requested pages being onlined.
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Keith Mannthey <kmannth@us.ibm.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__add_zone calls memmap_init_zone twice if memory gets attached to an empty
zone.  Once via init_currently_empty_zone and once explictly right after that
call.

Looks like this is currently not a bug, however the call is superfluous and
might lead to subtle bugs if memmap_init_zone gets changed.  So make sure it
is called only once.

Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixes the following compile error caused by commit
04753278 ("memory hotplug: register
section/node id to free"):

    CC      mm/memory_hotplug.o
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c: In function ‘put_page_bootmem’:
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c:82: error: implicit declaration of function ‘__free_pages_bootmem’
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c: At top level:
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c:87: warning: no previous prototype for ‘register_page_bootmem_info_section’
  make[2]: *** [mm/memory_hotplug.o] Error 1

[ Andrew: "Argh.  The -mm-only memory-hotplug-add-removable-to-sysfs-
  to-show-memblock-removability.patch debugging patch adds that include
  so nobody hit this before. ]
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is to free memmaps which is allocated by bootmem.

Freeing usemap is not necessary.  The pages of usemap may be necessary for
other sections.

If removing section is last section on the node, its section is the final user
of usemap page.  (usemaps are allocated on its section by previous patch.) But
it shouldn't be freed too, because the section must be logical offline state
which all pages are isolated against page allocater.  If it is freed, page
alloctor may use it which will be removed physically soon.  It will be
disaster.  So, this patch keeps it as it is.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch set is to free pages which is allocated by bootmem for
memory-hotremove.  Some structures of memory management are allocated by
bootmem.  ex) memmap, etc.

To remove memory physically, some of them must be freed according to
circumstance.  This patch set makes basis to free those pages, and free
memmaps.

Basic my idea is using remain members of struct page to remember information
of users of bootmem (section number or node id).  When the section is
removing, kernel can confirm it.  By this information, some issues can be
solved.

  1) When the memmap of removing section is allocated on other
     section by bootmem, it should/can be free.
  2) When the memmap of removing section is allocated on the
     same section, it shouldn't be freed. Because the section has to be
     logical memory offlined already and all pages must be isolated against
     page allocater. If it is freed, page allocator may use it which will
     be removed physically soon.
  3) When removing section has other section's memmap,
     kernel will be able to show easily which section should be removed
     before it for user. (Not implemented yet)
  4) When the above case 2), the page isolation will be able to check and skip
     memmap's page when logical memory offline (offline_pages()).
     Current page isolation code fails in this case because this page is
     just reserved page and it can't distinguish this pages can be
     removed or not. But, it will be able to do by this patch.
     (Not implemented yet.)
  5) The node information like pgdat has similar issues. But, this
     will be able to be solved too by this.
     (Not implemented yet, but, remembering node id in the pages.)

Fortunately, current bootmem allocator just keeps PageReserved flags,
and doesn't use any other members of page struct. The users of
bootmem doesn't use them too.

This patch:

This is to register information which is node or section's id.  Kernel can
distinguish which node/section uses the pages allcated by bootmem.  This is
basis for hot-remove sections or nodes.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All architectures use an effectively identical definition of online_page(), so
just make it common code.  x86-64, ia64, powerpc and sh are actually
identical; x86-32 is slightly different.

x86-32's differences arise because it puts its hotplug pages in the highmem
zone.  We can handle this in the generic code by inspecting the page to see if
its in highmem, and update the totalhigh_pages count appropriately.  This
leaves init_32.c:free_new_highpage with a single caller, so I folded it into
add_one_highpage_init.

I also removed an incorrect comment referring to the NUMA case; any NUMA
details have already been dealt with by the time online_page() is called.

[akpm@linux-foundation.org: fix indenting]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: NDave Hansen <dave@linux.vnet.ibm.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamez.hiroyu@jp.fujitsu.com>
Tested-by: NKAMEZAWA Hiroyuki <kamez.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Christoph Lameter <clameter@sgi.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Generic helper function to remove section mappings and sysfs entries for the
section of the memory we are removing.  offline_pages() correctly adjusted
zone and marked the pages reserved.

TODO: Yasunori Goto is working on patches to free up allocations from bootmem.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

- Add comments explaing how drain_pages() works.

- Eliminate useless functions

- Rename drain_all_local_pages to drain_all_pages(). It does drain
  all pages not only those of the local processor.

- Eliminate useless interrupt off / on sequences. drain_pages()
  disables interrupts on its own. The execution thread is
  pinned to processor by the caller. So there is no need to
  disable interrupts.

- Put drain_all_pages() declaration in gfp.h and remove the
  declarations from suspend.h and from mm/memory_hotplug.c

- Make software suspend call drain_all_pages(). The draining
  of processor local pages is may not the right approach if
  software suspend wants to support SMP. If they call drain_all_pages
  then we can make drain_pages() static.

[akpm@linux-foundation.org: fix build]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Daniel Walker <dwalker@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

i386 and x86-64 registers System RAM as IORESOURCE_MEM | IORESOURCE_BUSY.

But ia64 registers it as IORESOURCE_MEM only.
In addition, memory hotplug code registers new memory as IORESOURCE_MEM too.

This difference causes a failure of memory unplug of x86-64.  This patch
fixes it.

This patch adds IORESOURCE_BUSY to avoid potential overlap mapping by PCI
device.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Luck, Tony" <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We should unset migrate type "ISOLATE" when we successfully removed memory.
 But current code has BUG and cannot works well.

This patch also includes bugfix?  to change get_pageblock_flags to
get_pageblock_migratetype().

Thanks to Badari Pulavarty for finding this.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Current memory notifier has some defects yet.  (Fortunately, nothing uses
it.) This patch is to fix and rearrange for them.

  - Add information of start_pfn, nr_pages, and node id if node status is
    changes from/to memoryless node for callback functions.
    Callbacks can't do anything without those information.
  - Add notification going-online status.
    It is necessary for creating per node structure before the node's
    pages are available.
  - Move GOING_OFFLINE status notification after page isolation.
    It is good place for return memory like cache for callback,
    because returned page is not used again.
  - Make CANCEL events for rollingback when error occurs.
  - Delete MEM_MAPPING_INVALID notification. It will be not used.
  - Fix compile error of (un)register_memory_notifier().
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Spelling fixes in mm/.
Signed-off-by: NSimon Arlott <simon@fire.lp0.eu>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>

Now, arch dependent code around CONFIG_MEMORY_HOTREMOVE is a mess.
This patch cleans up them. This is against 2.6.23-rc6-mm1.

 - fix compile failure on ia64/ CONFIG_MEMORY_HOTPLUG && !CONFIG_MEMORY_HOTREMOVE case.
 - For !CONFIG_MEMORY_HOTREMOVE, add generic no-op remove_memory(),
   which returns -EINVAL.
 - removed remove_pages() only used in powerpc.
 - removed no-op remove_memory() in i386, sh, sparc64, x86_64.

 - only powerpc returns -ENOSYS at memory hot remove(no-op). changes it
   to return -EINVAL.

Note:
Currently, only ia64 supports CONFIG_MEMORY_HOTREMOVE. I welcome other
archs if there are requirements and testers.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Logic.
 - set all pages in  [start,end)  as isolated migration-type.
   by this, all free pages in the range will be not-for-use.
 - Migrate all LRU pages in the range.
 - Test all pages in the range's refcnt is zero or not.

Todo:
 - allocate migration destination page from better area.
 - confirm page_count(page)== 0 && PageReserved(page) page is safe to be freed..
 (I don't like this kind of page but..
 - Find out pages which cannot be migrated.
 - more running tests.
 - Use reclaim for unplugging other memory type area.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A clean up patch for "scanning memory resource [start, end)" operation.

Now, find_next_system_ram() function is used in memory hotplug, but this
interface is not easy to use and codes are complicated.

This patch adds walk_memory_resouce(start,len,arg,func) function.
The function 'func' is called per valid memory resouce range in [start,pfn).

[pbadari@us.ibm.com: Error handling in walk_memory_resource()]
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is necessary to know if nodes have memory since we have recently begun to
add support for memoryless nodes.  For that purpose we introduce a two new
node states: N_HIGH_MEMORY and N_NORMAL_MEMORY.

A node has its bit in N_HIGH_MEMORY set if it has any memory regardless of the
type of mmemory.  If a node has memory then it has at least one zone defined
in its pgdat structure that is located in the pgdat itself.

A node has its bit in N_NORMAL_MEMORY set if it has a lower zone than
ZONE_HIGHMEM.  This means it is possible to allocate memory that is not
subject to kmap.

N_HIGH_MEMORY and N_NORMAL_MEMORY can then be used in various places to insure
that we do the right thing when we encounter a memoryless node.

[akpm@linux-foundation.org: build fix]
[Lee.Schermerhorn@hp.com: update N_HIGH_MEMORY node state for memory hotadd]
[y-goto@jp.fujitsu.com: Fix memory hotplug + sparsemem build]
Signed-off-by: NLee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Acked-by: NBob Picco <bob.picco@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

zone->present_pages is updated in online_pages().  But, __add_zone() can be
called twice or more before calling online_pages().  So,
init_currenty_empty_zone() can be called unnecessary times.  It is cause of
memory leak of zone's wait_table.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix an oops experienced on the Cell architecture when init-time functions,
early_*(), are called at runtime.  It alters the call paths to make sure
that the callers explicitly say whether the call is being made on behalf of
a hotplug even, or happening at boot-time.

It has been compile tested on ppc64, ia64, s390, i386 and x86_64.
Acked-by: NArnd Bergmann <arndb@de.ibm.com>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: NAndy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The zone table is mostly not needed.  If we have a node in the page flags
then we can get to the zone via NODE_DATA() which is much more likely to be
already in the cpu cache.

In case of SMP and UP NODE_DATA() is a constant pointer which allows us to
access an exact replica of zonetable in the node_zones field.  In all of
the above cases there will be no need at all for the zone table.

The only remaining case is if in a NUMA system the node numbers do not fit
into the page flags.  In that case we make sparse generate a table that
maps sections to nodes and use that table to to figure out the node number.
 This table is sized to fit in a single cache line for the known 32 bit
NUMA platform which makes it very likely that the information can be
obtained without a cache miss.

For sparsemem the zone table seems to be have been fairly large based on
the maximum possible number of sections and the number of zones per node.
There is some memory saving by removing zone_table.  The main benefit is to
reduce the cache foootprint of the VM from the frequent lookups of zones.
Plus it simplifies the page allocator.

[akpm@osdl.org: build fix]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The api for hot-add memory already has a construct for finding nodes based on
an address, memory_add_physaddr_to_nid.  This patch allows the fucntion to do
something besides return 0.  It uses the nodes_add infomation to lookup to
node info for a hot add event.
Signed-off-by: NKeith Mannthey <kmannth@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Migate CONFIG_MEMORY_HOTPLUG to CONFIG_MEMORY_HOTPLUG_SPARSE where needed.
Signed-off-by: NKeith Mannthey <kmannth@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix up externs in memory_hotplug.c.  Cleanup.
Signed-off-by: NKeith Mannthey <kmannth@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ratelimit_pages in page-writeback.c is recalculated (in set_ratelimit())
every time a CPU is hot-added/removed.  But this value is not recalculated
when new pages are hot-added.

This patch fixes that problem by calling set_ratelimit() when new pages
are hot-added.

[akpm@osdl.org: cleanups]
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Change the list of memory nodes allowed to tasks in the top (root) nodeset
to dynamically track what cpus are online, using a call to a cpuset hook
from the memory hotplug code.  Make this top cpus file read-only.

On systems that have cpusets configured in their kernel, but that aren't
actively using cpusets (for some distros, this covers the majority of
systems) all tasks end up in the top cpuset.

If that system does support memory hotplug, then these tasks cannot make
use of memory nodes that are added after system boot, because the memory
nodes are not allowed in the top cpuset.  This is a surprising regression
over earlier kernels that didn't have cpusets enabled.

One key motivation for this change is to remain consistent with the
behaviour for the top_cpuset's 'cpus', which is also read-only, and which
automatically tracks the cpu_online_map.

This change also has the minor benefit that it fixes a long standing,
little noticed, minor bug in cpusets.  The cpuset performance tweak to
short circuit the cpuset_zone_allowed() check on systems with just a single
cpuset (see 'number_of_cpusets', in linux/cpuset.h) meant that simply
changing the 'mems' of the top_cpuset had no affect, even though the change
(the write system call) appeared to succeed.  With the following change,
that write to the 'mems' file fails -EACCES, and the 'mems' file stubbornly
refuses to be changed via user space writes.  Thus no one should be mislead
into thinking they've changed the top_cpusets's 'mems' when in affect they
haven't.

In order to keep the behaviour of cpusets consistent between systems
actively making use of them and systems not using them, this patch changes
the behaviour of the 'mems' file in the top (root) cpuset, making it read
only, and making it automatically track the value of node_online_map.  Thus
tasks in the top cpuset will have automatic use of hot plugged memory nodes
allowed by their cpuset.

[akpm@osdl.org: build fix]
[bunk@stusta.de: build fix]
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch is for collision check enhancement for memory hot add.

It's better to do resouce collision check before doing memory hot add,
which will touch memory management structures.

And add_section() should check section exists or not before calling
sparse_add_one_section(). (sparse_add_one_section() will do another
check anyway. but checking in memory_hotplug.c will be easy to understand.)
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: keith mannthey <kmannth@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

find_next_system_ram() is used to find available memory resource at onlining
newly added memory.  This patch fixes following problem.

find_next_system_ram() cannot catch this case.

Resource:      (start)-------------(end)
Section :                (start)-------------(end)
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Keith Mannthey <kmannth@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ioresouce handling code in memory hotplug allows not-aligned memory hot add.
But when memmap and other memory structures are initialized, parameters should
be aligned.  (if not aligned, initialization of mem_map will do wrong, it
assumes parameters are aligned.) This patch fix it.

And this patch allows ioresource collision check to handle -EEXIST.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Keith Mannthey <kmannth@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>