[PATCH] mm: ptd_alloc inline and out

It seems odd to me that, whereas pud_alloc and pmd_alloc test inline, only
calling out-of-line __pud_alloc __pmd_alloc if allocation needed,
pte_alloc_map and pte_alloc_kernel are entirely out-of-line.  Though it does
add a little to kernel size, change them to macros testing inline, calling
__pte_alloc or __pte_alloc_kernel to allocate out-of-line.  Mark none of them
as fastcalls, leave that to CONFIG_REGPARM or not.

It also seems more natural for the out-of-line functions to leave the offset
calculation and map to the inline, which has to do it anyway for the common
case.  At least mremap move wants __pte_alloc without _map.

Macros rather than inline functions, certainly to avoid the header file issues
which arise from CONFIG_HIGHPTE needing kmap_types.h, but also in case any
architectures I haven't built would have other such problems.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 62 insertions, 89 deletions

diff --git a/include/asm-generic/4level-fixup.h b/include/asm-generic/4level-fixup.h
index c20ec257ecc0..68c6fea994d9 100644
--- a/include/asm-generic/4level-fixup.h
+++ b/include/asm-generic/4level-fixup.h
@@ -10,14 +10,9 @@
 
 #define pud_t                           pgd_t
 
-#define pmd_alloc(mm, pud, address)                     \
-({      pmd_t *ret;                                     \
-        if (pgd_none(*pud))                             \
-                ret = __pmd_alloc(mm, pud, address);    \
-        else                                            \
-                ret = pmd_offset(pud, address);         \
-        ret;                                            \
-})
+#define pmd_alloc(mm, pud, address) \
+        ((unlikely(pgd_none(*(pud))) && __pmd_alloc(mm, pud, address))? \
+                NULL: pmd_offset(pud, address))
 
 #define pud_alloc(mm, pgd, address)     (pgd)
 #define pud_offset(pgd, start)          (pgd)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b9fa82b96d9e..22c2d6922c0e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -704,10 +704,6 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
 }
 
 extern int vmtruncate(struct inode * inode, loff_t offset);
-extern pud_t *FASTCALL(__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address));
-extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address));
-extern pte_t *FASTCALL(pte_alloc_kernel(pmd_t *pmd, unsigned long address));
-extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
 extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
 extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
 extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access);
@@ -760,32 +756,36 @@ struct shrinker;
 extern struct shrinker *set_shrinker(int, shrinker_t);
 extern void remove_shrinker(struct shrinker *shrinker);
 
-/*
- * On a two-level or three-level page table, this ends up being trivial. Thus
- * the inlining and the symmetry break with pte_alloc_map() that does all
- * of this out-of-line.
- */
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
+int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
+
 /*
  * The following ifdef needed to get the 4level-fixup.h header to work.
  * Remove it when 4level-fixup.h has been removed.
  */
-#ifdef CONFIG_MMU
-#ifndef __ARCH_HAS_4LEVEL_HACK 
+#if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
 static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
 {
-        if (pgd_none(*pgd))
-                return __pud_alloc(mm, pgd, address);
-        return pud_offset(pgd, address);
+        return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
+                NULL: pud_offset(pgd, address);
 }
 
 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 {
-        if (pud_none(*pud))
-                return __pmd_alloc(mm, pud, address);
-        return pmd_offset(pud, address);
+        return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
+                NULL: pmd_offset(pud, address);
 }
-#endif
-#endif /* CONFIG_MMU */
+#endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
+
+#define pte_alloc_map(mm, pmd, address)                 \
+        ((unlikely(!pmd_present(*(pmd))) && __pte_alloc(mm, pmd, address))? \
+                NULL: pte_offset_map(pmd, address))
+
+#define pte_alloc_kernel(pmd, address)                  \
+        ((unlikely(!pmd_present(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
+                NULL: pte_offset_kernel(pmd, address))
 
 extern void free_area_init(unsigned long * zones_size);
 extern void free_area_init_node(int nid, pg_data_t *pgdat,
diff --git a/mm/memory.c b/mm/memory.c
index 95a4553c75f7..4bdd1186b43b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -280,50 +280,39 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
         }
 }
 
-pte_t fastcall *pte_alloc_map(struct mm_struct *mm, pmd_t *pmd,
-                                unsigned long address)
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
 {
-        if (!pmd_present(*pmd)) {
-                struct page *new;
+        struct page *new;
 
-                spin_unlock(&mm->page_table_lock);
-                new = pte_alloc_one(mm, address);
-                spin_lock(&mm->page_table_lock);
-                if (!new)
-                        return NULL;
-                /*
-                 * Because we dropped the lock, we should re-check the
-                 * entry, as somebody else could have populated it..
-                 */
-                if (pmd_present(*pmd)) {
-                        pte_free(new);
-                        goto out;
-                }
+        spin_unlock(&mm->page_table_lock);
+        new = pte_alloc_one(mm, address);
+        spin_lock(&mm->page_table_lock);
+        if (!new)
+                return -ENOMEM;
+
+        if (pmd_present(*pmd))          /* Another has populated it */
+                pte_free(new);
+        else {
                 mm->nr_ptes++;
                 inc_page_state(nr_page_table_pages);
                 pmd_populate(mm, pmd, new);
         }
-out:
-        return pte_offset_map(pmd, address);
+        return 0;
 }
 
-pte_t fastcall * pte_alloc_kernel(pmd_t *pmd, unsigned long address)
+int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
 {
-        if (!pmd_present(*pmd)) {
-                pte_t *new;
-
-                new = pte_alloc_one_kernel(&init_mm, address);
-                if (!new)
-                        return NULL;
-
-                spin_lock(&init_mm.page_table_lock);
-                if (pmd_present(*pmd))
-                        pte_free_kernel(new);
-                else
-                        pmd_populate_kernel(&init_mm, pmd, new);
-                spin_unlock(&init_mm.page_table_lock);
-        }
-        return pte_offset_kernel(pmd, address);
+        pte_t *new = pte_alloc_one_kernel(&init_mm, address);
+        if (!new)
+                return -ENOMEM;
+
+        spin_lock(&init_mm.page_table_lock);
+        if (pmd_present(*pmd))          /* Another has populated it */
+                pte_free_kernel(new);
+        else
+                pmd_populate_kernel(&init_mm, pmd, new);
+        spin_unlock(&init_mm.page_table_lock);
+        return 0;
 }
 
 static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
@@ -2093,7 +2082,7 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
  * Allocate page upper directory.
  * We've already handled the fast-path in-line.
  */
-pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
 {
         pud_t *new;
 
@@ -2103,19 +2092,17 @@ pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr
         if (!new) {
                 if (mm != &init_mm)     /* Temporary bridging hack */
                         spin_lock(&mm->page_table_lock);
-                return NULL;
+                return -ENOMEM;
         }
 
         spin_lock(&mm->page_table_lock);
-        if (pgd_present(*pgd)) {
+        if (pgd_present(*pgd))          /* Another has populated it */
                 pud_free(new);
-                goto out;
-        }
-        pgd_populate(mm, pgd, new);
- out:
+        else
+                pgd_populate(mm, pgd, new);
         if (mm == &init_mm)             /* Temporary bridging hack */
                 spin_unlock(&mm->page_table_lock);
-        return pud_offset(pgd, address);
+        return 0;
 }
 #endif /* __PAGETABLE_PUD_FOLDED */
 
@@ -2124,7 +2111,7 @@ pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr
  * Allocate page middle directory.
  * We've already handled the fast-path in-line.
  */
-pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 {
         pmd_t *new;
 
@@ -2134,28 +2121,24 @@ pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr
         if (!new) {
                 if (mm != &init_mm)     /* Temporary bridging hack */
                         spin_lock(&mm->page_table_lock);
-                return NULL;
+                return -ENOMEM;
         }
 
         spin_lock(&mm->page_table_lock);
 #ifndef __ARCH_HAS_4LEVEL_HACK
-        if (pud_present(*pud)) {
+        if (pud_present(*pud))          /* Another has populated it */
                 pmd_free(new);
-                goto out;
-        }
-        pud_populate(mm, pud, new);
+        else
+                pud_populate(mm, pud, new);
 #else
-        if (pgd_present(*pud)) {
+        if (pgd_present(*pud))          /* Another has populated it */
                 pmd_free(new);
-                goto out;
-        }
-        pgd_populate(mm, pud, new);
+        else
+                pgd_populate(mm, pud, new);
 #endif /* __ARCH_HAS_4LEVEL_HACK */
-
- out:
         if (mm == &init_mm)             /* Temporary bridging hack */
                 spin_unlock(&mm->page_table_lock);
-        return pmd_offset(pud, address);
+        return 0;
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
diff --git a/mm/mremap.c b/mm/mremap.c
index ccf456477020..616facc3d28a 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -51,7 +51,6 @@ static pmd_t *alloc_new_pmd(struct mm_struct *mm, unsigned long addr)
         pgd_t *pgd;
         pud_t *pud;
         pmd_t *pmd = NULL;
-        pte_t *pte;
 
         /*
          * We do need page_table_lock: because allocators expect that.
@@ -66,12 +65,8 @@ static pmd_t *alloc_new_pmd(struct mm_struct *mm, unsigned long addr)
         if (!pmd)
                 goto out;
 
-        pte = pte_alloc_map(mm, pmd, addr);
-        if (!pte) {
+        if (!pmd_present(*pmd) && __pte_alloc(mm, pmd, addr))
                 pmd = NULL;
-                goto out;
-        }
-        pte_unmap(pte);
 out:
         spin_unlock(&mm->page_table_lock);
         return pmd;