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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 18:47:00 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 20:32:43 -0500
commit5f24ce5fd34c3ca1b3d10d30da754732da64d5c0 (patch)
treec82d27461f2adda210e77808b7dd04eaec017f2f /fs/proc/page.c
parent21ae5b01750f14140809508a478a4413792e0261 (diff)
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 'fs/proc/page.c')
-rw-r--r--fs/proc/page.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/fs/proc/page.c b/fs/proc/page.c
index b06c674624e6..6d8e6a9e93ab 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -116,15 +116,17 @@ u64 stable_page_flags(struct page *page)
116 if (PageHuge(page)) 116 if (PageHuge(page))
117 u |= 1 << KPF_HUGE; 117 u |= 1 << KPF_HUGE;
118 118
119 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
120
121 /* 119 /*
122 * Caveats on high order pages: 120 * Caveats on high order pages: page->_count will only be set
123 * PG_buddy will only be set on the head page; SLUB/SLQB do the same 121 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
124 * for PG_slab; SLOB won't set PG_slab at all on compound pages. 122 * SLOB won't set PG_slab at all on compound pages.
125 */ 123 */
124 if (PageBuddy(page))
125 u |= 1 << KPF_BUDDY;
126
127 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
128
126 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab); 129 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
127 u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy);
128 130
129 u |= kpf_copy_bit(k, KPF_ERROR, PG_error); 131 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
130 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); 132 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);