From: Andrea Arcangeli <aarcange@redhat.com>
Date: Thu, 13 Jan 2011 23:47:00 +0000 (-0800)
Subject: thp: remove PG_buddy
X-Git-Tag: v2.6.38-rc1~129
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5f24ce5fd34c3ca1b3d10d30da754732da64d5c0;p=pandora-kernel.git

thp: remove PG_buddy

PG_buddy can be converted to _mapcount == -2.  So the PG_compound_lock can
be added to page->flags without overflowing (because of the sparse section
bits increasing) with CONFIG_X86_PAE=y and CONFIG_X86_PAT=y.  This also
has to move the memory hotplug code from _mapcount to lru.next to avoid
any risk of clashes.  We can't use lru.next for PG_buddy removal, but
memory hotplug can use lru.next even more easily than the mapcount
instead.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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