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author | Andrea Arcangeli <aarcange@redhat.com> | 2011-01-13 23:47:00 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-14 01:32:43 (GMT) |
commit | 5f24ce5fd34c3ca1b3d10d30da754732da64d5c0 (patch) | |
tree | c82d27461f2adda210e77808b7dd04eaec017f2f /include/linux/mm.h | |
parent | 21ae5b01750f14140809508a478a4413792e0261 (diff) | |
download | linux-fsl-qoriq-5f24ce5fd34c3ca1b3d10d30da754732da64d5c0.tar.xz |
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>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r-- | include/linux/mm.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 2ec5138..7ab7d2b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -397,6 +397,27 @@ static inline void init_page_count(struct page *page) atomic_set(&page->_count, 1); } +/* + * PageBuddy() indicate that the page is free and in the buddy system + * (see mm/page_alloc.c). + */ +static inline int PageBuddy(struct page *page) +{ + return atomic_read(&page->_mapcount) == -2; +} + +static inline void __SetPageBuddy(struct page *page) +{ + VM_BUG_ON(atomic_read(&page->_mapcount) != -1); + atomic_set(&page->_mapcount, -2); +} + +static inline void __ClearPageBuddy(struct page *page) +{ + VM_BUG_ON(!PageBuddy(page)); + atomic_set(&page->_mapcount, -1); +} + void put_page(struct page *page); void put_pages_list(struct list_head *pages); |