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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:47:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:43 -0800
commit5f24ce5fd34c3ca1b3d10d30da754732da64d5c0 (patch)
treec82d27461f2adda210e77808b7dd04eaec017f2f /fs/proc/page.c
parent21ae5b01750f14140809508a478a4413792e0261 (diff)
downloadop-kernel-dev-5f24ce5fd34c3ca1b3d10d30da754732da64d5c0.zip
op-kernel-dev-5f24ce5fd34c3ca1b3d10d30da754732da64d5c0.tar.gz
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 b06c674..6d8e6a9 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -116,15 +116,17 @@ u64 stable_page_flags(struct page *page)
if (PageHuge(page))
u |= 1 << KPF_HUGE;
- u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
-
/*
- * Caveats on high order pages:
- * PG_buddy will only be set on the head page; SLUB/SLQB do the same
- * for PG_slab; SLOB won't set PG_slab at all on compound pages.
+ * Caveats on high order pages: page->_count will only be set
+ * -1 on the head page; SLUB/SLQB do the same for PG_slab;
+ * SLOB won't set PG_slab at all on compound pages.
*/
+ if (PageBuddy(page))
+ u |= 1 << KPF_BUDDY;
+
+ u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
+
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
- u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy);
u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
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