memory-hotplug: preparation to notify memory block's state at memory hot remove
authorWen Congyang <wency@cn.fujitsu.com>
Mon, 8 Oct 2012 23:33:58 +0000 (16:33 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 9 Oct 2012 07:23:02 +0000 (16:23 +0900)
commita16cee10c7ab994546ed98d9abfd4de74050124a
tree19b44bd2d32047f69f77a36145a9f2ebb6b41d53
parentc22331166b49b94b51424bb7fa1f83e09ad82734
memory-hotplug: preparation to notify memory block's state at memory hot remove

remove_memory() is called in two cases:
1. echo offline >/sys/devices/system/memory/memoryXX/state
2. hot remove a memory device

In the 1st case, the memory block's state is changed and the notification
that memory block's state changed is sent to userland after calling
remove_memory().  So user can notice memory block is changed.

But in the 2nd case, the memory block's state is not changed and the
notification is not also sent to userspcae even if calling
remove_memory().  So user cannot notice memory block is changed.

For adding the notification at memory hot remove, the patch just prepare
as follows:
1st case uses offline_pages() for offlining memory.
2nd case uses remove_memory() for offlining memory and changing memory block's
    state and notifing the information.

The patch does not implement notification to remove_memory().

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/base/memory.c
include/linux/memory_hotplug.h
mm/memory_hotplug.c