linux.git/mm/memory_hotplug.c, branch v2.6.26-rc7

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

memory hotplug: register section/node id to free

2008-04-28T15:58:25+00:00

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

hotplug-memory: make online_page() common

2008-04-28T15:58:17+00:00

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: Jeremy Fitzhardinge 
Acked-by: Dave Hansen 
Reviewed-by: KAMEZAWA Hiroyuki 
Tested-by: KAMEZAWA Hiroyuki 
Cc: Yasunori Goto 
Cc: Christoph Lameter 
Acked-by: Ingo Molnar 
Acked-by: Yasunori Goto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hotplug memory remove: generic __remove_pages() support

2008-04-28T15:58:17+00:00

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: Badari Pulavarty 
Acked-by: Yasunori Goto 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

driver core: memory: semaphore to mutex

2008-04-20T02:10:19+00:00

Signed-off-by: Daniel Walker 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

Page allocator: clean up pcp draining functions

2008-02-05T17:44:17+00:00

- 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: Christoph Lameter 
Acked-by: Mel Gorman 
Cc: "Rafael J. Wysocki" 
Cc: Daniel Walker 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds