linux-toradex.git/mm/memory_hotplug.c, branch v2.6.27.50

memory-hotplug: add sysfs removable attribute for hotplug memory remove

2008-07-24T17:47:21+00:00

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: Badari Pulavarty 
Signed-off-by: Mel Gorman 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory-hotplug: don't calculate vm_total_pages twice when rebuilding zonelists in online_pages()

2008-07-24T17:47:21+00:00

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: Kent Liu 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Yasunori Goto 
Cc: Andy Whitcroft 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory hotplug: small fixes to bootmem freeing for memory hotremove

2008-07-24T17:47:21+00:00

- 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: Yasunori Goto 
Cc: Andy Whitcroft 
Cc: Badari Pulavarty 
Cc: Yinghai Lu 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make register_page_bootmem_info_section() static

2008-07-24T17:47:21+00:00

Make the needlessly global register_page_bootmem_info_section() static.

Signed-off-by: Adrian Bunk 
Acked-by: Yasunori Goto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: drop unneeded pgdat argument from free_area_init_node()

2008-07-24T17:47:16+00:00

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: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory_hotplug: always initialize pageblock bitmap

2008-05-15T02:11:15+00:00

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 86051ca5eaf5e560113ec7673462804c54284456 ("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: Heiko Carstens 
Cc: Andy Whitcroft 
Cc: Dave Hansen 
Cc: Gerald Schaefer 
Cc: KAMEZAWA Hiroyuki 
Cc: Yasunori Goto 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory_hotplug: check for walk_memory_resource() failure in online_pages()

2008-05-15T02:11:14+00:00

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: Geoff Levand 
Cc: Yasunori Goto 
Cc: KAMEZAWA Hiroyuki 
Cc: Dave Hansen 
Cc: Keith Mannthey 
Cc: Christoph Lameter 
Cc: Paul Jackson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory hotplug: memmap_init_zone called twice

2008-05-15T02:11:14+00:00

__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 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Dave Hansen 
Signed-off-by: Heiko Carstens 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug.c must #include "internal.h"

2008-04-28T20:44:29+00:00

This patch fixes the following compile error caused by commit
04753278769f3b6c3b79a080edb52f21d83bf6e2 ("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: Adrian Bunk 
Signed-off-by: Linus Torvalds

memory hotplug: free memmaps allocated by bootmem

2008-04-28T15:58:26+00:00

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: Yasunori Goto 
Cc: Badari Pulavarty 
Cc: Yinghai Lu 
Cc: Yasunori Goto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds