[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>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4b077ec6c005d8e4221bf98cf0ca41c8b46eda49..7051fe450e96c2e0a9622edff3d0c602db523110 100644 (file)
--- 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)
 {
@@ -643,6 +513,71 @@ long do_get_mempolicy(int *policy, nodemask_t *nmask,
        return err;
 }
 
+/*
+ * 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
@@ -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.
  */