mm,thp: reduce ifdef'ery for THP in generic code
- pgtable-generic.c: Fold individual #ifdef for each helper into a top
level #ifdef. Makes code more readable
- Converted the stub helpers for !THP to BUILD_BUG() vs. runtime BUG()
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20151009133450.GA8597@node
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 29c57b2..3eabbbb 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -30,9 +30,19 @@
#endif
#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
extern int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,
pmd_t entry, int dirty);
+#else
+static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ pmd_t entry, int dirty)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
@@ -64,12 +74,12 @@
set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
return r;
}
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+#else
static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
unsigned long address,
pmd_t *pmdp)
{
- BUG();
+ BUILD_BUG();
return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
@@ -81,8 +91,21 @@
#endif
#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
-int pmdp_clear_flush_young(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmdp);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp);
+#else
+/*
+ * Despite relevant to THP only, this API is called from generic rmap code
+ * under PageTransHuge(), hence needs a dummy implementation for !THP
+ */
+static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
@@ -175,11 +198,11 @@
pmd_t old_pmd = *pmdp;
set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
}
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+#else
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
unsigned long address, pmd_t *pmdp)
{
- BUG();
+ BUILD_BUG();
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
@@ -248,7 +271,7 @@
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
{
- BUG();
+ BUILD_BUG();
return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 4885189..c9c59bb 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -82,12 +82,13 @@
}
#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,
pmd_t entry, int dirty)
{
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
int changed = !pmd_same(*pmdp, entry);
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
if (changed) {
@@ -95,10 +96,6 @@
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
return changed;
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
- BUG();
- return 0;
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
#endif
@@ -107,11 +104,7 @@
unsigned long address, pmd_t *pmdp)
{
int young;
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-#else
- BUG();
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
young = pmdp_test_and_clear_young(vma, address, pmdp);
if (young)
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
@@ -120,7 +113,6 @@
#endif
#ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
@@ -131,11 +123,9 @@
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
return pmd;
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
@@ -145,11 +135,9 @@
/* tlb flush only to serialize against gup-fast */
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
@@ -162,11 +150,9 @@
list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
pmd_huge_pte(mm, pmdp) = pgtable;
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/* no "address" argument so destroys page coloring of some arch */
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
{
@@ -185,11 +171,9 @@
}
return pgtable;
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef __HAVE_ARCH_PMDP_INVALIDATE
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
@@ -197,11 +181,9 @@
set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry));
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
#ifndef pmdp_collapse_flush
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
@@ -217,5 +199,5 @@
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
return pmd;
}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
