On Tue, Jan 25, 2011 at 03:05:16PM +0900, KAMEZAWA Hiroyuki wrote:

Based on 
2.6.38-rc2 + 
 mm-memcontrolc-fix-uninitialized-variable-use-in-mem_cgroup_move_parent.patch
==
From: KAMEZAWA Hiroyuki <redacted>

A fix up mem_cgroup_move_parent() which use compound_order() in
asynchrnous manner. This compound_order() may return unknown value
because we don't take lock. Use PageTransHuge() and HPAGE_SIZE instead of
it.

Also clean up for mem_cgroup_move_parent(). 
 - remove unnecessary initialization of local variable.
 - rename charge_size -> page_size
 - remove unnecessary (wrong) comment.
 - added a comment about THP.

Changelog:
 - fixed page size calculation for avoiding race.

Note:
 Current design take compound_page_lock() in caller of move_account().
 This should be revisited when we implement direct move_task of hugepage
 without splitting.

Signed-off-by: KAMEZAWA Hiroyuki <redacted>

Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>

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