Until now we can't offline memory blocks which contain hugepages because a
hugepage is considered as an unmovable page. But now with this patch
series, a hugepage has become movable, so by using hugepage migration we
can offline such memory blocks.
What's different from other users of hugepage migration is that we need to
decompose all the hugepages inside the target memory block into free buddy
pages after hugepage migration, because otherwise free hugepages remaining
in the memory block intervene the memory offlining. For this reason we
introduce new functions dissolve_free_huge_page() and
dissolve_free_huge_pages().
Other than that, what this patch does is straightforwardly to add hugepage
migration code, that is, adding hugepage code to the functions which scan
over pfn and collect hugepages to be migrated, and adding a hugepage
allocation function to alloc_migrate_target().
As for larger hugepages (1GB for x86_64), it's not easy to do hotremove
over them because it's larger than memory block. So we now simply leave
it to fail as it is.
[yongjun_wei@trendmicro.com.cn: remove duplicated include]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lock_device_hotplug() serializes hotplug & online/offline operations. The
lock is held in common sysfs online/offline interfaces and ACPI hotplug
code paths.
And here are the code paths:
- CPU & Mem online/offline via sysfs online
store_online()->lock_device_hotplug()
- Mem online via sysfs state:
store_mem_state()->lock_device_hotplug()
- ACPI CPU & Mem hot-add:
acpi_scan_bus_device_check()->lock_device_hotplug()
- ACPI CPU & Mem hot-delete:
acpi_scan_hot_remove()->lock_device_hotplug()
try_offline_node() off-lines a node if all memory sections and cpus are
removed on the node. It is called from acpi_processor_remove() and
acpi_memory_remove_memory()->remove_memory() paths, both of which are in
the ACPI hotplug code.
try_offline_node() calls stop_machine() to stop all cpus while checking
all cpu status with the assumption that the caller is not protected from
CPU hotplug or CPU online/offline operations. However, the caller is
always serialized with lock_device_hotplug(). Also, the code needs to be
properly serialized with a lock, not by stopping all cpus at a random
place with stop_machine().
This patch removes the use of stop_machine() in try_offline_node() and
adds comments to try_offline_node() and remove_memory() that
lock_device_hotplug() is required.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
add_memory() and remove_memory() can only handle a memory range aligned
with section. There are problems when an unaligned range is added and
then deleted as follows:
- add_memory() with an unaligned range succeeds, but __add_pages()
called from add_memory() adds a whole section of pages even though
a given memory range is less than the section size.
- remove_memory() to the added unaligned range hits BUG_ON() in
__remove_pages().
This patch changes add_memory() and remove_memory() to check if a given
memory range is aligned with section at the beginning. As the result,
add_memory() fails with -EINVAL when a given range is unaligned, and does
not add such memory range. This prevents remove_memory() to be called
with an unaligned range as well. Note that remove_memory() has to use
BUG_ON() since this function cannot fail.
[akpm@linux-foundation.org: avoid printk warnings]
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use "zone_is_initialized()" instead of "if (zone->wait_table)".
Simplify the code, no functional change.
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use "zone_is_empty()" instead of "if (zone->spanned_pages)".
Simplify the code, no functional change.
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I think we can remove "BUG_ON(start_pfn >= end_pfn)" in __offline_pages(),
because in memory_block_action() "nr_pages = PAGES_PER_SECTION * sections_per_block"
is always greater than 0.
memory_block_action()
offline_pages()
__offline_pages()
BUG_ON(start_pfn >= end_pfn)
In v2.6.32, If info->length==0, this way may hit this BUG_ON().
acpi_memory_disable_device()
remove_memory(info->start_addr, info->length)
offline_pages()
A later Fujitsu patch renamed this function and the BUG_ON() is
unnecessary.
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
online_pages() is called from memory_block_action() when a user requests
to online a memory block via sysfs. This function needs to return a
proper error value in case of error.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge first patch-bomb from Andrew Morton:
- various misc bits
- I'm been patchmonkeying ocfs2 for a while, as Joel and Mark have been
distracted. There has been quite a bit of activity.
- About half the MM queue
- Some backlight bits
- Various lib/ updates
- checkpatch updates
- zillions more little rtc patches
- ptrace
- signals
- exec
- procfs
- rapidio
- nbd
- aoe
- pps
- memstick
- tools/testing/selftests updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (445 commits)
tools/testing/selftests: don't assume the x bit is set on scripts
selftests: add .gitignore for kcmp
selftests: fix clean target in kcmp Makefile
selftests: add .gitignore for vm
selftests: add hugetlbfstest
self-test: fix make clean
selftests: exit 1 on failure
kernel/resource.c: remove the unneeded assignment in function __find_resource
aio: fix wrong comment in aio_complete()
drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode
drivers/memstick/host/r592.c: convert to module_pci_driver
drivers/memstick/host/jmb38x_ms: convert to module_pci_driver
pps-gpio: add device-tree binding and support
drivers/pps/clients/pps-gpio.c: convert to module_platform_driver
drivers/pps/clients/pps-gpio.c: convert to devm_* helpers
drivers/parport/share.c: use kzalloc
Documentation/accounting/getdelays.c: avoid strncpy in accounting tool
aoe: update internal version number to v83
aoe: update copyright date
aoe: perform I/O completions in parallel
...
Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages. And change code which directly adjusts totalram_pages to
use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.
Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.
This patch also fixes two bugs:
1) enhances virtio_balloon driver to adjust totalhigh_pages when
reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
memory.
We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.
[akpm@linux-foundation.org: remove ifdef, per Wanpeng Li, virtio_balloon.c cleanup, per Sergei]
[akpm@linux-foundation.org: export adjust_managed_page_count() to modules, for drivers/virtio/virtio_balloon.c]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to simpilify management of totalram_pages and
zone->managed_pages, make __free_pages_bootmem() only available at boot
time. With this change applied, __free_pages_bootmem() will only be
used by bootmem.c and nobootmem.c at boot time, so mark it as __init.
Other callers of __free_pages_bootmem() have been converted to use
free_reserved_page(), which handles totalram_pages and
zone->managed_pages in a safer way.
This patch also fix a bug in free_pagetable() for x86_64, which should
increase zone->managed_pages instead of zone->present_pages when freeing
reserved pages.
And now we have managed_pages_count_lock to protect totalram_pages and
zone->managed_pages, so remove the redundant ppb_lock lock in
put_page_bootmem(). This greatly simplifies the locking rules.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During early boot-up, iomem_resource is set up from the boot descriptor
table, such as EFI Memory Table and e820. Later,
acpi_memory_device_add() calls add_memory() for each ACPI memory device
object as it enumerates ACPI namespace. This add_memory() call is
expected to fail in register_memory_resource() at boot since
iomem_resource has been set up from EFI/e820. As a result, add_memory()
returns -EEXIST, which acpi_memory_device_add() handles as the normal
case.
This scheme works fine, but the following error message is logged for
every ACPI memory device object during boot-up.
"System RAM resource %pR cannot be added\n"
This patch changes register_memory_resource() to use pr_debug() for the
message as it shows up under the normal case.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmzone.h documents node_size_lock (which pgdat_resize_lock() locks) as
follows:
* Must be held any time you expect node_start_pfn, node_present_pages
* or node_spanned_pages stay constant. [...]
So actually hold it when we update node_present_pages in __offline_pages().
[akpm@linux-foundation.org: fix build]
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmzone.h documents node_size_lock (which pgdat_resize_lock() locks) as
follows:
* Must be held any time you expect node_start_pfn, node_present_pages
* or node_spanned_pages stay constant. [...]
So actually hold it when we update node_present_pages in online_pages().
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the definitions of offline_pages() and remove_memory()
for CONFIG_MEMORY_HOTREMOVE to memory_hotplug.h, where they belong,
and make them static inline.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now that the memory offlining should be taken care of by the
companion device offlining code in acpi_scan_hot_remove(), the
ACPI memory hotplug driver doesn't need to offline it in
remove_memory() any more. Moreover, since the return value of
remove_memory() is not used, it's better to make it be a void
function and trigger a BUG() if the memory scheduled for removal is
not offline.
Change the code in accordance with the above observations.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Since offline_memory_block(mem) is functionally equivalent to
device_offline(&mem->dev), make the only caller of the former use
the latter instead and drop offline_memory_block() entirely.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Fix printk format warnings in mm/memory_hotplug.c by using "%pa":
mm/memory_hotplug.c: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 2 has type 'resource_size_t' [-Wformat]
mm/memory_hotplug.c: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 3 has type 'resource_size_t' [-Wformat]
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During ACPI memory hotplug configuration bind memory blocks residing
in modules removable through the standard ACPI mechanism to struct
acpi_device objects associated with ACPI namespace objects
representing those modules. Accordingly, unbind those memory blocks
from the struct acpi_device objects when the memory modules in
question are being removed.
When "offline" operation for devices representing memory blocks is
introduced, this will allow the ACPI core's device hot-remove code to
use it to carry out remove_memory() for those memory blocks and check
the results of that before it actually removes the modules holding
them from the system.
Since walk_memory_range() is used for accessing all memory blocks
corresponding to a given ACPI namespace object, it is exported from
memory_hotplug.c so that the code in acpi_memhotplug.c can use it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
PFN_PHYS() is a phys_addr_t, which can be u32 or u64.
Fix the build warning when phys_addr_t is u32.
mm/memory_hotplug.c: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 2 has type 'unsigned int' [-Wformat]: => 1685:3
mm/memory_hotplug.c: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 3 has type 'unsigned int' [-Wformat]: => 1685:3
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__remove_pages() is only necessary for CONFIG_MEMORY_HOTREMOVE. PowerPC
pseries will return -EOPNOTSUPP if unsupported.
Adding an #ifdef causes several other functions it depends on to also
become unnecessary, which saves in .text when disabled (it's disabled in
most defconfigs besides powerpc, including x86). remove_memory_block()
becomes static since it is not referenced outside of
drivers/base/memory.c.
Build tested on x86 and powerpc with CONFIG_MEMORY_HOTREMOVE both enabled
and disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change __remove_pages() to call release_mem_region_adjustable(). This
allows a requested memory range to be released from the iomem_resource
table even if it does not match exactly to an resource entry but still
fits into. The resource entries initialized at bootup usually cover the
whole contiguous memory ranges and may not necessarily match with the
size of memory hot-delete requests.
If release_mem_region_adjustable() failed, __remove_pages() emits a
warning message and continues to proceed as it was the case with
release_mem_region(). release_mem_region(), which is defined to
__release_region(), emits a warning message and returns no error since a
void function.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by : Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: T Makphaibulchoke <tmac@hp.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a typo "end_pft" in the comment of walk_memory_range().
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zone->wait_table may be allocated from bootmem, it can not be freed.
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
remove_memory() calls walk_memory_range() with [start_pfn, end_pfn), where
end_pfn is exclusive in this range. Therefore, end_pfn needs to be set to
the next page of the end address.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ensure_zone_is_initialized() checks if a zone is in a empty & not
initialized state (typically occuring after it is created in memory
hotplugging), and, if so, calls init_currently_empty_zone() to
initialize the zone.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add 2 helpers (zone_end_pfn() and zone_spans_pfn()) to reduce code
duplication.
This also switches to using them in compaction (where an additional
variable needed to be renamed), page_alloc, vmstat, memory_hotplug, and
kmemleak.
Note that in compaction.c I avoid calling zone_end_pfn() repeatedly
because I expect at some point the sycronization issues with start_pfn &
spanned_pages will need fixing, either by actually using the seqlock or
clever memory barrier usage.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Hansen <dave@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No functional change, but the only purpose of the offlining argument to
migrate_pages() etc, was to ensure that __unmap_and_move() could migrate a
KSM page for memory hotremove (which took ksm_thread_mutex) but not for
other callers. Now all cases are safe, remove the arg.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Function put_page_bootmem() is used to free pages allocated by bootmem
allocator, so it should increase totalram_pages when freeing pages into
the buddy system.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: Chris Clayton <chris2553@googlemail.com>
Cc: "Rafael J . Wysocki" <rjw@sisk.pl>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the node is offlined, there is no memory/cpu on the node. If a
sleep task runs on a cpu of this node, it will be migrated to the cpu on
the other node. So we can clear cpu-to-node mapping.
[akpm@linux-foundation.org: numa_clear_node() and numa_set_node() can no longer be __cpuinit]
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_offline_node() will be needed in the tristate
drivers/acpi/processor_driver.c.
The node will be offlined when all memory/cpu on the node have been
hotremoved. So we need the function try_offline_node() in cpu-hotplug
path.
If the memory-hotplug is disabled, and cpu-hotplug is enabled
1. no memory no the node
we don't online the node, and cpu's node is the nearest node.
2. the node contains some memory
the node has been onlined, and cpu's node is still needed
to migrate the sleep task on the cpu to the same node.
So we do nothing in try_offline_node() in this case.
[rientjes@google.com: export the function try_offline_node() fix]
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since there is no way to guarentee the address of pgdat/zone is not on
stack of any kernel threads or used by other kernel objects without
reference counting or other symchronizing method, we cannot reset
node_data and free pgdat when offlining a node. Just reset pgdat to 0
and reuse the memory when the node is online again.
The problem is suggested by Kamezawa Hiroyuki. The idea is from Wen
Congyang.
NOTE: If we don't reset pgdat to 0, the WARN_ON in free_area_init_node()
will be triggered.
[akpm@linux-foundation.org: fix warning when CONFIG_NEED_MULTIPLE_NODES=n]
[akpm@linux-foundation.org: fix the warning again again]
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We call hotadd_new_pgdat() to allocate memory to store node_data. So we
should free it when removing a node.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a new function try_offline_node() to remove sysfs file of node
when all memory sections of this node are removed. If some memory
sections of this node are not removed, this function does nothing.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory is added, we update zone's and pgdat's start_pfn and
spanned_pages in __add_zone(). So we should revert them when the memory
is removed.
The patch adds a new function __remove_zone() to do this.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently __remove_section for SPARSEMEM_VMEMMAP does nothing. But even
if we use SPARSEMEM_VMEMMAP, we can unregister the memory_section.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In __remove_section(), we locked pgdat_resize_lock when calling
sparse_remove_one_section(). This lock will disable irq. But we don't
need to lock the whole function. If we do some work to free pagetables
in free_section_usemap(), we need to call flush_tlb_all(), which need
irq enabled. Otherwise the WARN_ON_ONCE() in smp_call_function_many()
will be triggered.
If we lock the whole sparse_remove_one_section(), then we come to this call trace:
------------[ cut here ]------------
WARNING: at kernel/smp.c:461 smp_call_function_many+0xbd/0x260()
Hardware name: PRIMEQUEST 1800E
......
Call Trace:
smp_call_function_many+0xbd/0x260
smp_call_function+0x3b/0x50
on_each_cpu+0x3b/0xc0
flush_tlb_all+0x1c/0x20
remove_pagetable+0x14e/0x1d0
vmemmap_free+0x18/0x20
sparse_remove_one_section+0xf7/0x100
__remove_section+0xa2/0xb0
__remove_pages+0xa0/0xd0
arch_remove_memory+0x6b/0xc0
remove_memory+0xb8/0xf0
acpi_memory_device_remove+0x53/0x96
acpi_device_remove+0x90/0xb2
__device_release_driver+0x7c/0xf0
device_release_driver+0x2f/0x50
acpi_bus_remove+0x32/0x6d
acpi_bus_trim+0x91/0x102
acpi_bus_hot_remove_device+0x88/0x16b
acpi_os_execute_deferred+0x27/0x34
process_one_work+0x20e/0x5c0
worker_thread+0x12e/0x370
kthread+0xee/0x100
ret_from_fork+0x7c/0xb0
---[ end trace 25e85300f542aa01 ]---
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For removing memmap region of sparse-vmemmap which is allocated bootmem,
memmap region of sparse-vmemmap needs to be registered by
get_page_bootmem(). So the patch searches pages of virtual mapping and
registers the pages by get_page_bootmem().
NOTE: register_page_bootmem_memmap() is not implemented for ia64,
ppc, s390, and sparc. So introduce CONFIG_HAVE_BOOTMEM_INFO_NODE
and revert register_page_bootmem_info_node() when platform doesn't
support it.
It's implemented by adding a new Kconfig option named
CONFIG_HAVE_BOOTMEM_INFO_NODE, which will be automatically selected
by memory-hotplug feature fully supported archs(currently only on
x86_64).
Since we have 2 config options called MEMORY_HOTPLUG and
MEMORY_HOTREMOVE used for memory hot-add and hot-remove separately,
and codes in function register_page_bootmem_info_node() are only
used for collecting infomation for hot-remove, so reside it under
MEMORY_HOTREMOVE.
Besides page_isolation.c selected by MEMORY_ISOLATION under
MEMORY_HOTPLUG is also such case, move it too.
[mhocko@suse.cz: put register_page_bootmem_memmap inside CONFIG_MEMORY_HOTPLUG_SPARSE]
[linfeng@cn.fujitsu.com: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_bootmem_info_node()]
[mhocko@suse.cz: remove the arch specific functions without any implementation]
[linfeng@cn.fujitsu.com: mm/Kconfig: move auto selects from MEMORY_HOTPLUG to MEMORY_HOTREMOVE as needed]
[rientjes@google.com: fix defined but not used warning]
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wu Jianguo <wujianguo@huawei.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For removing memory, we need to remove page tables. But it depends on
architecture. So the patch introduce arch_remove_memory() for removing
page table. Now it only calls __remove_pages().
Note: __remove_pages() for some archtecuture is not implemented
(I don't know how to implement it for s390).
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When (hot)adding memory into system, /sys/firmware/memmap/X/{end, start,
type} sysfs files are created. But there is no code to remove these
files. This patch implements the function to remove them.
We cannot free firmware_map_entry which is allocated by bootmem because
there is no way to do so when the system is up. But we can at least
remember the address of that memory and reuse the storage when the
memory is added next time.
This patch also introduces a new list map_entries_bootmem to link the
map entries allocated by bootmem when they are removed, and a lock to
protect it. And these entries will be reused when the memory is
hot-added again.
The idea is suggestted by Andrew Morton.
NOTE: It is unsafe to return an entry pointer and release the
map_entries_lock. So we should not hold the map_entries_lock
separately in firmware_map_find_entry() and
firmware_map_remove_entry(). Hold the map_entries_lock across find
and remove /sys/firmware/memmap/X operation.
And also, users of these two functions need to be careful to
hold the lock when using these two functions.
[tangchen@cn.fujitsu.com: Hold spinlock across find|remove /sys operation]
[tangchen@cn.fujitsu.com: fix the wrong comments of map_entries]
[tangchen@cn.fujitsu.com: reuse the storage of /sys/firmware/memmap/X/ allocated by bootmem]
[tangchen@cn.fujitsu.com: fix section mismatch problem]
[tangchen@cn.fujitsu.com: fix the doc format in drivers/firmware/memmap.c]
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Julian Calaby <julian.calaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We remove the memory like this:
1. lock memory hotplug
2. offline a memory block
3. unlock memory hotplug
4. repeat 1-3 to offline all memory blocks
5. lock memory hotplug
6. remove memory(TODO)
7. unlock memory hotplug
All memory blocks must be offlined before removing memory. But we don't
hold the lock in the whole operation. So we should check whether all
memory blocks are offlined before step6. Otherwise, kernel maybe
panicked.
Offlining a memory block and removing a memory device can be two
different operations. Users can just offline some memory blocks without
removing the memory device. For this purpose, the kernel has held
lock_memory_hotplug() in __offline_pages(). To reuse the code for
memory hot-remove, we repeat step 1-3 to offline all the memory blocks,
repeatedly lock and unlock memory hotplug, but not hold the memory
hotplug lock in the whole operation.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory can't be offlined when CONFIG_MEMCG is selected. For example:
there is a memory device on node 1. The address range is [1G, 1.5G).
You will find 4 new directories memory8, memory9, memory10, and memory11
under the directory /sys/devices/system/memory/.
If CONFIG_MEMCG is selected, we will allocate memory to store page
cgroup when we online pages. When we online memory8, the memory stored
page cgroup is not provided by this memory device. But when we online
memory9, the memory stored page cgroup may be provided by memory8. So
we can't offline memory8 now. We should offline the memory in the
reversed order.
When the memory device is hotremoved, we will auto offline memory
provided by this memory device. But we don't know which memory is
onlined first, so offlining memory may fail. In such case, iterate
twice to offline the memory. 1st iterate: offline every non primary
memory block. 2nd iterate: offline primary (i.e. first added) memory
block.
This idea is suggested by KOSAKI Motohiro.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
