Fix CONFIG_TRANSPARENT_HUGEPAGE=y CONFIG_SMP=n CONFIG_DEBUG_VM=y
CONFIG_DEBUG_SPINLOCK=n kernel: spin_is_locked() is then always false,
and so triggers some BUGs in Transparent HugePage codepaths.
asm-generic/bug.h mentions this problem, and provides a WARN_ON_SMP(x);
but being too lazy to add VM_BUG_ON_SMP, BUG_ON_SMP, WARN_ON_SMP_ONCE,
VM_WARN_ON_SMP_ONCE, just test NR_CPUS != 1 in the existing VM_BUG_ONs.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
mm/huge_memory.c | 4 ++--
mm/swap.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
--- 3.3-rc2/mm/huge_memory.c 2012-01-20 08:42:35.304020840 -0800
+++ linux/mm/huge_memory.c 2012-02-07 15:37:18.581666053 -0800
@@ -2083,7 +2083,7 @@ static void collect_mm_slot(struct mm_sl
{
struct mm_struct *mm = mm_slot->mm;
- VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock));
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
if (khugepaged_test_exit(mm)) {
/* free mm_slot */
@@ -2113,7 +2113,7 @@ static unsigned int khugepaged_scan_mm_s
int progress = 0;
VM_BUG_ON(!pages);
- VM_BUG_ON(!spin_is_locked(&khugepaged_mm_lock));
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
if (khugepaged_scan.mm_slot)
mm_slot = khugepaged_scan.mm_slot;
--- 3.3-rc2/mm/swap.c 2012-01-20 08:42:35.324020840 -0800
+++ linux/mm/swap.c 2012-02-07 15:37:18.581666053 -0800
@@ -659,7 +659,7 @@ void lru_add_page_tail(struct zone* zone
VM_BUG_ON(!PageHead(page));
VM_BUG_ON(PageCompound(page_tail));
VM_BUG_ON(PageLRU(page_tail));
- VM_BUG_ON(!spin_is_locked(&zone->lru_lock));
+ VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&zone->lru_lock));
SetPageLRU(page_tail);
--
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