x86: PAT: move track untrack pfnmap stubs to asm-generic

Impact: Cleanup and branch hints only.

Move the track and untrack pfn stub routines from memory.c to asm-generic.
Also add unlikely to pfnmap related calls in fork and exit path.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/pgtable.h

@@ -339,12 +339,10 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 
 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
 
+#ifndef __ASSEMBLY__
 /* Indicate that x86 has its own track and untrack pfn vma functions */
-#define track_pfn_vma_new track_pfn_vma_new
-#define track_pfn_vma_copy track_pfn_vma_copy
-#define untrack_pfn_vma untrack_pfn_vma
+#define __HAVE_PFNMAP_TRACKING
 
-#ifndef __ASSEMBLY__
 #define __HAVE_PHYS_MEM_ACCESS_PROT
 struct file;
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

include/asm-generic/pgtable.h

@@ -293,6 +293,52 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 #define arch_flush_lazy_cpu_mode()	do {} while (0)
 #endif
 
+#ifndef __HAVE_PFNMAP_TRACKING
+/*
+ * Interface that can be used by architecture code to keep track of
+ * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
+ *
+ * track_pfn_vma_new is called when a _new_ pfn mapping is being established
+ * for physical range indicated by pfn and size.
+ */
+static inline int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+					unsigned long pfn, unsigned long size)
+{
+	return 0;
+}
+
+/*
+ * Interface that can be used by architecture code to keep track of
+ * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
+ *
+ * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
+ * copied through copy_page_range().
+ */
+static inline int track_pfn_vma_copy(struct vm_area_struct *vma)
+{
+	return 0;
+}
+
+/*
+ * Interface that can be used by architecture code to keep track of
+ * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
+ *
+ * untrack_pfn_vma is called while unmapping a pfnmap for a region.
+ * untrack can be called for a specific region indicated by pfn and size or
+ * can be for the entire vma (in which case size can be zero).
+ */
+static inline void untrack_pfn_vma(struct vm_area_struct *vma,
+					unsigned long pfn, unsigned long size)
+{
+}
+#else
+extern int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+				unsigned long pfn, unsigned long size);
+extern int track_pfn_vma_copy(struct vm_area_struct *vma);
+extern void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
+				unsigned long size);
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* _ASM_GENERIC_PGTABLE_H */

include/linux/mm.h

@@ -163,12 +163,6 @@ static inline int is_pfn_mapping(struct vm_area_struct *vma)
 	return (vma->vm_flags & VM_PFNMAP);
 }
 
-extern int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
-				unsigned long pfn, unsigned long size);
-extern int track_pfn_vma_copy(struct vm_area_struct *vma);
-extern void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
-				unsigned long size);
-
 /*
  * vm_fault is filled by the the pagefault handler and passed to the vma's
  * ->fault function. The vma's ->fault is responsible for returning a bitmask

mm/memory.c

@@ -99,50 +99,6 @@ int randomize_va_space __read_mostly =
 					2;
 #endif
 
-#ifndef track_pfn_vma_new
-/*
- * Interface that can be used by architecture code to keep track of
- * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
- *
- * track_pfn_vma_new is called when a _new_ pfn mapping is being established
- * for physical range indicated by pfn and size.
- */
-int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
-			unsigned long pfn, unsigned long size)
-{
-	return 0;
-}
-#endif
-
-#ifndef track_pfn_vma_copy
-/*
- * Interface that can be used by architecture code to keep track of
- * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
- *
- * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
- * copied through copy_page_range().
- */
-int track_pfn_vma_copy(struct vm_area_struct *vma)
-{
-	return 0;
-}
-#endif
-
-#ifndef untrack_pfn_vma
-/*
- * Interface that can be used by architecture code to keep track of
- * memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
- *
- * untrack_pfn_vma is called while unmapping a pfnmap for a region.
- * untrack can be called for a specific region indicated by pfn and size or
- * can be for the entire vma (in which case size can be zero).
- */
-void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
-			unsigned long size)
-{
-}
-#endif
-
 static int __init disable_randmaps(char *s)
 {
 	randomize_va_space = 0;
@@ -713,7 +669,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	if (is_vm_hugetlb_page(vma))
 		return copy_hugetlb_page_range(dst_mm, src_mm, vma);
 
-	if (is_pfn_mapping(vma)) {
+	if (unlikely(is_pfn_mapping(vma))) {
 		/*
 		 * We do not free on error cases below as remove_vma
 		 * gets called on error from higher level routine
@@ -969,7 +925,7 @@ unsigned long unmap_vmas(struct mmu_gather **tlbp,
 		if (vma->vm_flags & VM_ACCOUNT)
 			*nr_accounted += (end - start) >> PAGE_SHIFT;
 
-		if (is_pfn_mapping(vma))
+		if (unlikely(is_pfn_mapping(vma)))
 			untrack_pfn_vma(vma, 0, 0);
 
 		while (start != end) {