Re: [PATCH v3 05/13] mm/debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING

Saved write support was added to track the write bit of a pte after marking the
pte protnone. This was done so that AUTONUMA can convert a write pte to protnone
and still track the old write bit. When converting it back we set the pte write
bit correctly thereby avoiding a write fault again. Hence enable the test only
when CONFIG_NUMA_BALANCING is enabled and use protnone protflags.

Signed-off-by: Aneesh Kumar K.V <redacted>
---
 mm/debug_vm_pgtable.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 28f9d0558c20..5c0680836fe9 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c

@@ -119,10 +119,14 @@ static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 {
 	pte_t pte = pfn_pte(pfn, prot);
 
+	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
+		return;
+
 	pr_debug("Validating PTE saved write\n");
 	WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
 	WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
 }
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
 {

@@ -235,6 +239,9 @@ static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 {
 	pmd_t pmd = pfn_pmd(pfn, prot);
 
+	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
+		return;
+
 	pr_debug("Validating PMD saved write\n");
 	WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
 	WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));

@@ -1020,8 +1027,8 @@ static int __init debug_vm_pgtable(void)
 	pmd_huge_tests(pmdp, pmd_aligned, prot);
 	pud_huge_tests(pudp, pud_aligned, prot);
 
-	pte_savedwrite_tests(pte_aligned, prot);
-	pmd_savedwrite_tests(pmd_aligned, prot);
+	pte_savedwrite_tests(pte_aligned, protnone);
+	pmd_savedwrite_tests(pmd_aligned, protnone);
 
 	pte_unmap_unlock(ptep, ptl);