[PATCH] SwapMig: Extend parameters for migrate_pages()

Extend the parameters of migrate_pages() to allow the caller control over the
fate of successfully migrated or impossible to migrate pages.

Swap migration and direct migration will have the same interface after this
patch so that patches can be independently applied to the policy layer and the
core migration code.

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, 22 insertions, 5 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 20d5ad39fa41..30bdafba52d8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -429,6 +429,19 @@ 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)
 {
@@ -481,10 +494,13 @@ long do_mbind(unsigned long start, unsigned long len,
               (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) ? &pagelist : NULL);
         err = PTR_ERR(vma);
         if (!IS_ERR(vma)) {
+                int nr_failed = 0;
+
                 err = mbind_range(vma, start, end, new);
                 if (!list_empty(&pagelist))
-                        migrate_pages(&pagelist, NULL);
-                if (!err && !list_empty(&pagelist) && (flags & MPOL_MF_STRICT))
+                        nr_failed = swap_pages(&pagelist);
+
+                if (!err && nr_failed && (flags & MPOL_MF_STRICT))
                         err = -EIO;
         }
         if (!list_empty(&pagelist))
@@ -635,11 +651,12 @@ int do_migrate_pages(struct mm_struct *mm,
         down_read(&mm->mmap_sem);
         check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nodes,
                         flags | MPOL_MF_DISCONTIG_OK, &pagelist);
+
         if (!list_empty(&pagelist)) {
-                migrate_pages(&pagelist, NULL);
-                if (!list_empty(&pagelist))
-                        count = putback_lru_pages(&pagelist);
+                count = swap_pages(&pagelist);
+                putback_lru_pages(&pagelist);
         }
+
         up_read(&mm->mmap_sem);
         return count;
 }