[PATCH] Move page migration related functions near do_migrate_pages()

Group page migration functions in mempolicy.c

Add a forward declaration for migrate_page_add (like gather_stats()) and use
our new found mobility to group all page migration related function around
do_migrate_pages().

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 138 insertions, 132 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4b077ec6c005..7051fe450e96 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -183,55 +183,9 @@ static struct mempolicy *mpol_new(int mode, nodemask_t *nodes)
         return policy;
 }
 
-/* Check if we are the only process mapping the page in question */
-static inline int single_mm_mapping(struct mm_struct *mm,
-                        struct address_space *mapping)
-{
-        struct vm_area_struct *vma;
-        struct prio_tree_iter iter;
-        int rc = 1;
-
-        spin_lock(&mapping->i_mmap_lock);
-        vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
-                if (mm != vma->vm_mm) {
-                        rc = 0;
-                        goto out;
-                }
-        list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
-                if (mm != vma->vm_mm) {
-                        rc = 0;
-                        goto out;
-                }
-out:
-        spin_unlock(&mapping->i_mmap_lock);
-        return rc;
-}
-
-/*
- * Add a page to be migrated to the pagelist
- */
-static void migrate_page_add(struct vm_area_struct *vma,
-        struct page *page, struct list_head *pagelist, unsigned long flags)
-{
-        /*
-         * Avoid migrating a page that is shared by others and not writable.
-         */
-        if ((flags & MPOL_MF_MOVE_ALL) || !page->mapping || PageAnon(page) ||
-            mapping_writably_mapped(page->mapping) ||
-            single_mm_mapping(vma->vm_mm, page->mapping)) {
-                int rc = isolate_lru_page(page);
-
-                if (rc == 1)
-                        list_add(&page->lru, pagelist);
-                /*
-                 * If the isolate attempt was not successful then we just
-                 * encountered an unswappable page. Something must be wrong.
-                 */
-                WARN_ON(rc == 0);
-        }
-}
-
 static void gather_stats(struct page *, void *);
+static void migrate_page_add(struct vm_area_struct *vma,
+        struct page *page, struct list_head *pagelist, unsigned long flags);
 
 /* Scan through pages checking if pages follow certain conditions. */
 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -440,90 +394,6 @@ static int contextualize_policy(int mode, nodemask_t *nodes)
         return mpol_check_policy(mode, nodes);
 }
 
-static int swap_pages(struct list_head *pagelist)
-{
-        LIST_HEAD(moved);
-        LIST_HEAD(failed);
-        int n;
-
-        n = migrate_pages(pagelist, NULL, &moved, &failed);
-        putback_lru_pages(&failed);
-        putback_lru_pages(&moved);
-
-        return n;
-}
-
-long do_mbind(unsigned long start, unsigned long len,
-                unsigned long mode, nodemask_t *nmask, unsigned long flags)
-{
-        struct vm_area_struct *vma;
-        struct mm_struct *mm = current->mm;
-        struct mempolicy *new;
-        unsigned long end;
-        int err;
-        LIST_HEAD(pagelist);
-
-        if ((flags & ~(unsigned long)(MPOL_MF_STRICT |
-                                      MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
-            || mode > MPOL_MAX)
-                return -EINVAL;
-        if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE))
-                return -EPERM;
-
-        if (start & ~PAGE_MASK)
-                return -EINVAL;
-
-        if (mode == MPOL_DEFAULT)
-                flags &= ~MPOL_MF_STRICT;
-
-        len = (len + PAGE_SIZE - 1) & PAGE_MASK;
-        end = start + len;
-
-        if (end < start)
-                return -EINVAL;
-        if (end == start)
-                return 0;
-
-        if (mpol_check_policy(mode, nmask))
-                return -EINVAL;
-
-        new = mpol_new(mode, nmask);
-        if (IS_ERR(new))
-                return PTR_ERR(new);
-
-        /*
-         * If we are using the default policy then operation
-         * on discontinuous address spaces is okay after all
-         */
-        if (!new)
-                flags |= MPOL_MF_DISCONTIG_OK;
-
-        PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len,
-                        mode,nodes_addr(nodes)[0]);
-
-        down_write(&mm->mmap_sem);
-        vma = check_range(mm, start, end, nmask,
-                          flags | MPOL_MF_INVERT, &pagelist);
-
-        err = PTR_ERR(vma);
-        if (!IS_ERR(vma)) {
-                int nr_failed = 0;
-
-                err = mbind_range(vma, start, end, new);
-                if (!list_empty(&pagelist))
-                        nr_failed = swap_pages(&pagelist);
-
-                if (!err && nr_failed && (flags & MPOL_MF_STRICT))
-                        err = -EIO;
-        }
-        if (!list_empty(&pagelist))
-                putback_lru_pages(&pagelist);
-
-        up_write(&mm->mmap_sem);
-        mpol_free(new);
-        return err;
-}
-
 /* Set the process memory policy */
 long do_set_mempolicy(int mode, nodemask_t *nodes)
 {
@@ -644,6 +514,71 @@ long do_get_mempolicy(int *policy, nodemask_t *nmask,
 }
 
 /*
+ * page migration
+ */
+
+/* Check if we are the only process mapping the page in question */
+static inline int single_mm_mapping(struct mm_struct *mm,
+                        struct address_space *mapping)
+{
+        struct vm_area_struct *vma;
+        struct prio_tree_iter iter;
+        int rc = 1;
+
+        spin_lock(&mapping->i_mmap_lock);
+        vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
+                if (mm != vma->vm_mm) {
+                        rc = 0;
+                        goto out;
+                }
+        list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+                if (mm != vma->vm_mm) {
+                        rc = 0;
+                        goto out;
+                }
+out:
+        spin_unlock(&mapping->i_mmap_lock);
+        return rc;
+}
+
+/*
+ * Add a page to be migrated to the pagelist
+ */
+static void migrate_page_add(struct vm_area_struct *vma,
+        struct page *page, struct list_head *pagelist, unsigned long flags)
+{
+        /*
+         * Avoid migrating a page that is shared by others and not writable.
+         */
+        if ((flags & MPOL_MF_MOVE_ALL) || !page->mapping || PageAnon(page) ||
+            mapping_writably_mapped(page->mapping) ||
+            single_mm_mapping(vma->vm_mm, page->mapping)) {
+                int rc = isolate_lru_page(page);
+
+                if (rc == 1)
+                        list_add(&page->lru, pagelist);
+                /*
+                 * If the isolate attempt was not successful then we just
+                 * encountered an unswappable page. Something must be wrong.
+                 */
+                WARN_ON(rc == 0);
+        }
+}
+
+static int swap_pages(struct list_head *pagelist)
+{
+        LIST_HEAD(moved);
+        LIST_HEAD(failed);
+        int n;
+
+        n = migrate_pages(pagelist, NULL, &moved, &failed);
+        putback_lru_pages(&failed);
+        putback_lru_pages(&moved);
+
+        return n;
+}
+
+/*
  * For now migrate_pages simply swaps out the pages from nodes that are in
  * the source set but not in the target set. In the future, we would
  * want a function that moves pages between the two nodesets in such
@@ -673,6 +608,77 @@ int do_migrate_pages(struct mm_struct *mm,
         return count;
 }
 
+long do_mbind(unsigned long start, unsigned long len,
+                unsigned long mode, nodemask_t *nmask, unsigned long flags)
+{
+        struct vm_area_struct *vma;
+        struct mm_struct *mm = current->mm;
+        struct mempolicy *new;
+        unsigned long end;
+        int err;
+        LIST_HEAD(pagelist);
+
+        if ((flags & ~(unsigned long)(MPOL_MF_STRICT |
+                                      MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+            || mode > MPOL_MAX)
+                return -EINVAL;
+        if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE))
+                return -EPERM;
+
+        if (start & ~PAGE_MASK)
+                return -EINVAL;
+
+        if (mode == MPOL_DEFAULT)
+                flags &= ~MPOL_MF_STRICT;
+
+        len = (len + PAGE_SIZE - 1) & PAGE_MASK;
+        end = start + len;
+
+        if (end < start)
+                return -EINVAL;
+        if (end == start)
+                return 0;
+
+        if (mpol_check_policy(mode, nmask))
+                return -EINVAL;
+
+        new = mpol_new(mode, nmask);
+        if (IS_ERR(new))
+                return PTR_ERR(new);
+
+        /*
+         * If we are using the default policy then operation
+         * on discontinuous address spaces is okay after all
+         */
+        if (!new)
+                flags |= MPOL_MF_DISCONTIG_OK;
+
+        PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len,
+                        mode,nodes_addr(nodes)[0]);
+
+        down_write(&mm->mmap_sem);
+        vma = check_range(mm, start, end, nmask,
+                          flags | MPOL_MF_INVERT, &pagelist);
+
+        err = PTR_ERR(vma);
+        if (!IS_ERR(vma)) {
+                int nr_failed = 0;
+
+                err = mbind_range(vma, start, end, new);
+                if (!list_empty(&pagelist))
+                        nr_failed = swap_pages(&pagelist);
+
+                if (!err && nr_failed && (flags & MPOL_MF_STRICT))
+                        err = -EIO;
+        }
+        if (!list_empty(&pagelist))
+                putback_lru_pages(&pagelist);
+
+        up_write(&mm->mmap_sem);
+        mpol_free(new);
+        return err;
+}
+
 /*
  * User space interface with variable sized bitmaps for nodelists.
  */