linux-stable.git/mm/memory_hotplug.c, branch linux-2.6.34.y

mm: fix return value of scan_lru_pages in memory unplug

2011-04-17T20:15:40+00:00

commit f8f72ad5396987e05a42cf7eff826fb2a15ff148 upstream.

scan_lru_pages returns pfn. So, it's type should be "unsigned long"
not "int".

Note: I guess this has been work until now because memory hotplug tester's
      machine has not very big memory....
      physical address < 32bit << PAGE_SHIFT.

Reported-by: KOSAKI Motohiro 
Signed-off-by: KAMEZAWA Hiroyuki 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker

memory hotplug: fix next block calculation in is_removable

2011-01-06T23:07:47+00:00

commit 0dcc48c15f63ee86c2fcd33968b08d651f0360a5 upstream.

next_active_pageblock() is for finding next _used_ freeblock.  It skips
several blocks when it finds there are a chunk of free pages lager than
pageblock.  But it has 2 bugs.

  1. We have no lock. page_order(page) - pageblock_order can be minus.
  2. pageblocks_stride += is wrong. it should skip page_order(p) of pages.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Michal Hocko 
Cc: Wu Fengguang 
Cc: Mel Gorman 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker

mm: introduce dump_page() and print symbolic flag names

2010-03-12T23:52:28+00:00

- introduce dump_page() to print the page info for debugging some error
  condition.

- convert three mm users: bad_page(), print_bad_pte() and memory offline
  failure.

- print an extra field: the symbolic names of page->flags

Example dump_page() output:

[  157.521694] page:ffffea0000a7cba8 count:2 mapcount:1 mapping:ffff88001c901791 index:0x147
[  157.525570] page flags: 0x100000000100068(uptodate|lru|active|swapbacked)

Signed-off-by: Wu Fengguang 
Cc: Ingo Molnar 
Cc: Alex Chiang 
Cc: Rik van Riel 
Cc: Andi Kleen 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory-hotplug: create /sys/firmware/memmap entry for new memory

2010-03-06T19:26:25+00:00

A memmap is a directory in sysfs which includes 3 text files: start, end
and type.  For example:

start: 	0x100000
end:	0x7e7b1cff
type:	System RAM

Interface firmware_map_add was not called explicitly.  Remove it and add
function firmware_map_add_hotplug as hotplug interface of memmap.

Each memory entry has a memmap in sysfs, When we hot-add new memory, sysfs
does not export memmap entry for it.  We add a call in function add_memory
to function firmware_map_add_hotplug.

Add a new function add_sysfs_fw_map_entry() to create memmap entry, it
will be called when initialize memmap and hot-add memory.

[akpm@linux-foundation.org: un-kernedoc a no longer kerneldoc comment]
Signed-off-by: Shaohui Zheng 
Acked-by: Andi Kleen 
Acked-by: Yasunori Goto 
Reviewed-by: Wu Fengguang 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix section mismatch in memory_hotplug.c

2009-12-15T16:53:20+00:00

__free_pages_bootmem() is a __meminit function - which has been called
from put_pages_bootmem thus causes a section mismatch warning.

 We were warned by the following warning:

  LD      mm/built-in.o
WARNING: mm/built-in.o(.text+0x26b22): Section mismatch in reference
from the function put_page_bootmem() to the function
.meminit.text:__free_pages_bootmem()
The function put_page_bootmem() references
the function __meminit __free_pages_bootmem().
This is often because put_page_bootmem lacks a __meminit
annotation or the annotation of __free_pages_bootmem is wrong.

Signed-off-by: Rakib Mullick 
Cc: Yasunori Goto 
Cc: Badari Pulavarty 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: memory_hotplug: make offline_pages() static

2009-12-15T16:53:20+00:00

It has no references outside memory_hotplug.c.

Cc: "Rafael J. Wysocki" 
Cc: Andi Kleen 
Cc: Gerald Schaefer 
Cc: KOSAKI Motohiro 
Cc: Yasunori Goto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ksm: memory hotremove migration only

2009-12-15T16:53:20+00:00

The previous patch enables page migration of ksm pages, but that soon gets
into trouble: not surprising, since we're using the ksm page lock to lock
operations on its stable_node, but page migration switches the page whose
lock is to be used for that.  Another layer of locking would fix it, but
do we need that yet?

Do we actually need page migration of ksm pages?  Yes, memory hotremove
needs to offline sections of memory: and since we stopped allocating ksm
pages with GFP_HIGHUSER, they will tend to be GFP_HIGHUSER_MOVABLE
candidates for migration.

But KSM is currently unconscious of NUMA issues, happily merging pages
from different NUMA nodes: at present the rule must be, not to use
MADV_MERGEABLE where you care about NUMA.  So no, NUMA page migration of
ksm pages does not make sense yet.

So, to complete support for ksm swapping we need to make hotremove safe.
ksm_memory_callback() take ksm_thread_mutex when MEM_GOING_OFFLINE and
release it when MEM_OFFLINE or MEM_CANCEL_OFFLINE.  But if mapped pages
are freed before migration reaches them, stable_nodes may be left still
pointing to struct pages which have been removed from the system: the
stable_node needs to identify a page by pfn rather than page pointer, then
it can safely prune them when MEM_OFFLINE.

And make NUMA migration skip PageKsm pages where it skips PageReserved.
But it's only when we reach unmap_and_move() that the page lock is taken
and we can be sure that raised pagecount has prevented a PageAnon from
being upgraded: so add offlining arg to migrate_pages(), to migrate ksm
page when offlining (has sufficient locking) but reject it otherwise.

Signed-off-by: Hugh Dickins 
Cc: Izik Eidus 
Cc: Andrea Arcangeli 
Cc: Chris Wright 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined

2009-12-15T16:53:13+00:00

When memory is hot-removed, its node must be cleared in N_HIGH_MEMORY if
there are no present pages left.

In such a situation, kswapd must also be stopped since it has nothing left
to do.

Signed-off-by: David Rientjes 
Signed-off-by: Lee Schermerhorn 
Cc: Christoph Lameter 
Cc: Yasunori Goto 
Cc: Mel Gorman 
Cc: Rafael J. Wysocki 
Cc: Rik van Riel 
Cc: KAMEZAWA Hiroyuki 
Cc: Lee Schermerhorn 
Cc: Mel Gorman 
Cc: Randy Dunlap 
Cc: Nishanth Aravamudan 
Cc: Andi Kleen 
Cc: David Rientjes 
Cc: Adam Litke 
Cc: Andy Whitcroft 
Cc: Eric Whitney 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move inc_zone_page_state(NR_ISOLATED) to just isolated place

2009-12-15T16:53:12+00:00

Christoph pointed out inc_zone_page_state(NR_ISOLATED) should be placed
in right after isolate_page().

This patch does it.

Reviewed-by: Christoph Lameter 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: allow memory hotplug and hibernation in the same kernel

2009-11-18T01:40:33+00:00

Allow memory hotplug and hibernation in the same kernel

Memory hotplug and hibernation were exclusive in Kconfig.  This is
obviously a problem for distribution kernels who want to support both in
the same image.

After some discussions with Rafael and others the only problem is with
parallel memory hotadd or removal while a hibernation operation is in
process.  It was also working for s390 before.

This patch removes the Kconfig level exclusion, and simply makes the
memory add / remove functions grab the pm_mutex to exclude against
hibernation.

Fixes a regression - old kernels didn't exclude memory hotadd and
hibernation.

Signed-off-by: Andi Kleen 
Cc: Gerald Schaefer 
Cc: KOSAKI Motohiro 
Cc: Yasunori Goto 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds