mm: fix UP THP spin_is_locked BUGs (b9980cdc) · Commits · 戴 / test

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@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -2083,7 +2083,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
		{
		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_slot(unsigned int pages,
		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;

mm/swap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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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