OpenCloudOS-Kernel/include
Yasuaki Ishimatsu 6677e3eaf4 memory-hotplug: check whether all memory blocks are offlined or not when removing memory
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>
2013-02-23 17:50:11 -08:00
..
acpi Merge branch 'acpi-cleanup' 2013-02-15 13:58:30 +01:00
asm-generic Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2013-02-21 17:54:03 -08:00
clocksource arm: arch_timer: add missing inline in stub function 2013-02-11 15:16:05 -08:00
crypto
drm Merge branch 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel 2013-01-11 07:52:48 +10:00
keys
linux memory-hotplug: check whether all memory blocks are offlined or not when removing memory 2013-02-23 17:50:11 -08:00
math-emu
media
memory
misc
net Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-02-21 17:40:58 -08:00
pcmcia
ras
rdma UAPI: Remove empty Kbuild files 2013-01-02 17:36:10 -08:00
rxrpc
scsi SCSI misc on 20121212 2012-12-13 19:20:31 -08:00
sound ASoC: Final updates for v3.9 2013-02-16 15:48:48 +01:00
target target: Introduce TCM_NO_SENSE 2013-01-10 20:06:08 -08:00
trace ACPI and power management updates for 3.9-rc1 2013-02-20 11:26:56 -08:00
uapi Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2013-02-21 17:41:38 -08:00
video video: s3c-fb: fix typo in definition of VIDCON1_VSTATUS_FRONTPORCH value 2013-02-21 17:22:18 -08:00
xen Bugfixes: 2012-12-18 12:26:54 -08:00
Kbuild UAPI: Remove empty Kbuild files 2013-01-02 17:36:10 -08:00