linux-toradex.git/mm/memory_hotplug.c, branch v3.14.3

mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug

2014-01-24T00:36:52+00:00

We don't need to do register_memory_resource() under
lock_memory_hotplug() since it has its own lock and doesn't make any
callbacks.

Also register_memory_resource return NULL on failure so we don't have
anything to cleanup at this point.

The reason for this rfc is I was doing some experiments with hotplugging
of memory on some of our larger systems.  While it seems to work, it can
be quite slow.  With some preliminary digging I found that
lock_memory_hotplug is clearly ripe for breakup.

It could be broken up per nid or something but it also covers the
online_page_callback.  The online_page_callback shouldn't be very hard
to break out.

Also there is the issue of various structures(wmarks come to mind) that
are only updated under the lock_memory_hotplug that would need to be
dealt with.

Cc: Tang Chen 
Cc: Wen Congyang 
Cc: Kamezawa Hiroyuki 
Reviewed-by: Yasuaki Ishimatsu 
Cc: "Rafael J. Wysocki" 
Cc: Hedi 
Cc: Mike Travis 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: print more details for bad_page()

2014-01-24T00:36:50+00:00

bad_page() is cool in that it prints out a bunch of data about the page.
But, I can never remember which page flags are good and which are bad,
or whether ->index or ->mapping is required to be NULL.

This patch allows bad/dump_page() callers to specify a string about why
they are dumping the page and adds explanation strings to a number of
places.  It also adds a 'bad_flags' argument to bad_page(), which it
then dumps out separately from the flags which are actually set.

This way, the messages will show specifically why the page was bad,
*specifically* which flags it is complaining about, if it was a page
flag combination which was the problem.

[akpm@linux-foundation.org: switch to pr_alert]
Signed-off-by: Dave Hansen 
Reviewed-by: Christoph Lameter 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: use memblock apis for early memory allocations

2014-01-22T00:19:47+00:00

Correct ensure_zone_is_initialized() function description according to
the introduced memblock APIs for early memory allocations.

Signed-off-by: Grygorii Strashko 
Signed-off-by: Santosh Shilimkar 
Cc: "Rafael J. Wysocki" 
Cc: Arnd Bergmann 
Cc: Christoph Lameter 
Cc: Greg Kroah-Hartman 
Cc: H. Peter Anvin 
Cc: Johannes Weiner 
Cc: KAMEZAWA Hiroyuki 
Cc: Konrad Rzeszutek Wilk 
Cc: Michal Hocko 
Cc: Paul Walmsley 
Cc: Pavel Machek 
Cc: Russell King 
Cc: Tejun Heo 
Cc: Tony Lindgren 
Cc: Yinghai Lu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memblock: remove unnecessary inclusions of bootmem.h

2014-01-22T00:19:46+00:00

Clean-up to remove depedency with bootmem headers.

Signed-off-by: Grygorii Strashko 
Signed-off-by: Santosh Shilimkar 
Reviewed-by: Tejun Heo 
Cc: Yinghai Lu 
Cc: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Cc: Christoph Lameter 
Cc: H. Peter Anvin 
Cc: Johannes Weiner 
Cc: KAMEZAWA Hiroyuki 
Cc: Konrad Rzeszutek Wilk 
Cc: Michal Hocko 
Cc: Paul Walmsley 
Cc: Pavel Machek 
Cc: Russell King 
Cc: Tony Lindgren 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memblock, mem_hotplug: make memblock skip hotpluggable regions if needed

2014-01-22T00:19:45+00:00

Linux kernel cannot migrate pages used by the kernel.  As a result,
hotpluggable memory used by the kernel won't be able to be hot-removed.
To solve this problem, the basic idea is to prevent memblock from
allocating hotpluggable memory for the kernel at early time, and arrange
all hotpluggable memory in ACPI SRAT(System Resource Affinity Table) as
ZONE_MOVABLE when initializing zones.

In the previous patches, we have marked hotpluggable memory regions with
MEMBLOCK_HOTPLUG flag in memblock.memory.

In this patch, we make memblock skip these hotpluggable memory regions
in the default top-down allocation function if movable_node boot option
is specified.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Tang Chen 
Signed-off-by: Zhang Yanfei 
Cc: "H. Peter Anvin" 
Cc: "Rafael J . Wysocki" 
Cc: Chen Tang 
Cc: Gong Chen 
Cc: Ingo Molnar 
Cc: Jiang Liu 
Cc: Johannes Weiner 
Cc: Lai Jiangshan 
Cc: Larry Woodman 
Cc: Len Brown 
Cc: Liu Jiang 
Cc: Mel Gorman 
Cc: Michal Nazarewicz 
Cc: Minchan Kim 
Cc: Prarit Bhargava 
Cc: Rik van Riel 
Cc: Taku Izumi 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Thomas Renninger 
Cc: Toshi Kani 
Cc: Vasilis Liaskovitis 
Cc: Wanpeng Li 
Cc: Wen Congyang 
Cc: Yasuaki Ishimatsu 
Cc: Yinghai Lu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mem-hotplug: introduce movable_node boot option

2013-11-13T03:09:09+00:00

The hot-Pluggable field in SRAT specifies which memory is hotpluggable.
As we mentioned before, if hotpluggable memory is used by the kernel, it
cannot be hot-removed.  So memory hotplug users may want to set all
hotpluggable memory in ZONE_MOVABLE so that the kernel won't use it.

Memory hotplug users may also set a node as movable node, which has
ZONE_MOVABLE only, so that the whole node can be hot-removed.

But the kernel cannot use memory in ZONE_MOVABLE.  By doing this, the
kernel cannot use memory in movable nodes.  This will cause NUMA
performance down.  And other users may be unhappy.

So we need a way to allow users to enable and disable this functionality.
In this patch, we introduce movable_node boot option to allow users to
choose to not to consume hotpluggable memory at early boot time and later
we can set it as ZONE_MOVABLE.

To achieve this, the movable_node boot option will control the memblock
allocation direction.  That said, after memblock is ready, before SRAT is
parsed, we should allocate memory near the kernel image as we explained in
the previous patches.  So if movable_node boot option is set, the kernel
does the following:

1. After memblock is ready, make memblock allocate memory bottom up.
2. After SRAT is parsed, make memblock behave as default, allocate memory
   top down.

Users can specify "movable_node" in kernel commandline to enable this
functionality.  For those who don't use memory hotplug or who don't want
to lose their NUMA performance, just don't specify anything.  The kernel
will work as before.

Signed-off-by: Tang Chen 
Signed-off-by: Zhang Yanfei 
Suggested-by: Kamezawa Hiroyuki 
Suggested-by: Ingo Molnar 
Acked-by: Tejun Heo 
Acked-by: Toshi Kani 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Wanpeng Li 
Cc: Thomas Renninger 
Cc: Yinghai Lu 
Cc: Jiang Liu 
Cc: Wen Congyang 
Cc: Lai Jiangshan 
Cc: Yasuaki Ishimatsu 
Cc: Taku Izumi 
Cc: Mel Gorman 
Cc: Michal Nazarewicz 
Cc: Minchan Kim 
Cc: Rik van Riel 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/sparsemem: use PAGES_PER_SECTION to remove redundant nr_pages parameter

2013-11-13T03:09:06+00:00

For below functions,

- sparse_add_one_section()
- kmalloc_section_memmap()
- __kmalloc_section_memmap()
- __kfree_section_memmap()

they are always invoked to operate on one memory section, so it is
redundant to always pass a nr_pages parameter, which is the page numbers
in one section.  So we can directly use predefined macro PAGES_PER_SECTION
instead of passing the parameter.

Signed-off-by: Zhang Yanfei 
Cc: Wen Congyang 
Cc: Tang Chen 
Cc: Toshi Kani 
Cc: Yasuaki Ishimatsu 
Cc: Yinghai Lu 
Cc: Yasunori Goto 
Cc: Andy Whitcroft 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cpu/mem hotplug: add try_online_node() for cpu_up()

2013-11-13T03:09:04+00:00

cpu_up() has #ifdef CONFIG_MEMORY_HOTPLUG code blocks, which call
mem_online_node() to put its node online if offlined and then call
build_all_zonelists() to initialize the zone list.

These steps are specific to memory hotplug, and should be managed in
mm/memory_hotplug.c.  lock_memory_hotplug() should also be held for the
whole steps.

For this reason, this patch replaces mem_online_node() with
try_online_node(), which performs the whole steps with
lock_memory_hotplug() held.  try_online_node() is named after
try_offline_node() as they have similar purpose.

There is no functional change in this patch.

Signed-off-by: Toshi Kani 
Reviewed-by: Yasuaki Ishimatsu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: use pfn_to_nid() instead of page_to_nid(pfn_to_page())

2013-11-13T03:09:04+00:00

Use "pfn_to_nid(pfn)" instead of "page_to_nid(pfn_to_page(pfn))".

Signed-off-by: Xishi Qiu 
Acked-by: Yasuaki Ishimatsu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: rename the function is_memblock_offlined_cb()

2013-11-13T03:09:04+00:00

A is_memblock_offlined() return or 1 means memory block is offlined, but
is_memblock_offlined_cb() returning 1 means memory block is not offlined,
this will confuse somebody, so rename the function.

Signed-off-by: Xishi Qiu 
Acked-by: Yasuaki Ishimatsu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds