linux-toradex.git/mm/memory_hotplug.c, branch v2.6.33.6

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

mm/memory_hotplug: fix section mismatch

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

With CONFIG_MEMORY_HOTPLUG I got following warning:

WARNING: vmlinux.o(.text+0x1276b0): Section mismatch in reference from
the function hotadd_new_pgdat() to the function
.meminit.text:free_area_init_node()
The function hotadd_new_pgdat() references
the function __meminit free_area_init_node().
This is often because hotadd_new_pgdat lacks a __meminit
annotation or the annotation of free_area_init_node is wrong.

Use __ref to fix this.

Signed-off-by: Hidetoshi Seto 
Cc: Minchan Kim 
Cc: Mel Gorman 
Cc: Yasunori Goto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

walk system ram range

2009-09-23T14:39:41+00:00

Originally, walk_memory_resource() was introduced to traverse all memory
of "System RAM" for detecting memory hotplug/unplug range.  For doing so,
flags of IORESOUCE_MEM|IORESOURCE_BUSY was used and this was enough for
memory hotplug.

But for using other purpose, /proc/kcore, this may includes some firmware
area marked as IORESOURCE_BUSY | IORESOUCE_MEM.  This patch makes the
check strict to find out busy "System RAM".

Note: PPC64 keeps their own walk_memory_resouce(), which walk through
ppc64's lmb informaton.  Because old kclist_add() is called per lmb, this
patch makes no difference in behavior, finally.

And this patch removes CONFIG_MEMORY_HOTPLUG check from this function.
Because pfn_valid() just show "there is memmap or not* and cannot be used
for "there is physical memory or not", this function is useful in generic
to scan physical memory range.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: WANG Cong 
Cc: Américo Wang 
Cc: David Rientjes 
Cc: Roland Dreier 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory hotplug: fix updating of num_physpages for hot plugged memory

2009-09-22T14:17:38+00:00

Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages.  The amount of what actually is usable as storage
should instead be used as a basis here.

In line with that, the memory hotplug code should update num_physpages in
a way that it retains its original (post-boot) meaning; in particular,
decreasing the value should at best be done with great care - this patch
doesn't try to ever decrease this value at all as it doesn't really seem
meaningful to do so.

Signed-off-by: Jan Beulich 
Acked-by: Rusty Russell 
Cc: Yasunori Goto 
Cc: Badari Pulavarty 
Cc: Minchan Kim 
Cc: Mel Gorman 
Cc: Dave Hansen 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory hotplug: update zone pcp at memory online

2009-09-22T14:17:25+00:00

In my test, 128M memory is hot added, but zone's pcp batch is 0, which is
an obvious error.  When pages are onlined, zone pcp should be updated
accordingly.

[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Shaohua Li 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: Yakui Zhao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds