[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>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index eb591eaad1b7461af182422db9bc285230a68d6a..389d1c382e208c2f05cabf86367624a9feb73b12 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -178,7 +178,8 @@ extern int vm_swappiness;
 #ifdef CONFIG_MIGRATION
 extern int isolate_lru_page(struct page *p);
 extern int putback_lru_pages(struct list_head *l);
-extern int migrate_pages(struct list_head *l, struct list_head *t);
+extern int migrate_pages(struct list_head *l, struct list_head *t,
+               struct list_head *moved, struct list_head *failed);
 #endif
 
 #ifdef CONFIG_MMU

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 20d5ad39fa411052a2f9554cf293b58ba926ddfd..30bdafba52d8aa120ea7ccc764e7402545abedf3 100644 (file)
--- 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;
 }

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 73ba4046ed272eb290cea68dca37d02a5ae64092..5eecb514ccea00171c94f96c6d12d361b361a2db 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -670,10 +670,10 @@ retry:
  * list. The direct migration patchset
  * extends this function to avoid the use of swap.
  */
-int migrate_pages(struct list_head *l, struct list_head *t)
+int migrate_pages(struct list_head *from, struct list_head *to,
+                 struct list_head *moved, struct list_head *failed)
 {
        int retry;
-       LIST_HEAD(failed);
        int nr_failed = 0;
        int pass = 0;
        struct page *page;
@@ -686,12 +686,12 @@ int migrate_pages(struct list_head *l, struct list_head *t)
 redo:
        retry = 0;
 
-       list_for_each_entry_safe(page, page2, l, lru) {
+       list_for_each_entry_safe(page, page2, from, lru) {
                cond_resched();
 
                if (page_count(page) == 1) {
                        /* page was freed from under us. So we are done. */
-                       move_to_lru(page);
+                       list_move(&page->lru, moved);
                        continue;
                }
                /*
@@ -722,7 +722,7 @@ redo:
                if (PageAnon(page) && !PageSwapCache(page)) {
                        if (!add_to_swap(page, GFP_KERNEL)) {
                                unlock_page(page);
-                               list_move(&page->lru, &failed);
+                               list_move(&page->lru, failed);
                                nr_failed++;
                                continue;
                        }
@@ -732,8 +732,10 @@ redo:
                 * Page is properly locked and writeback is complete.
                 * Try to migrate the page.
                 */
-               if (!swap_page(page))
+               if (!swap_page(page)) {
+                       list_move(&page->lru, moved);
                        continue;
+               }
 retry_later:
                retry++;
        }
@@ -743,9 +745,6 @@ retry_later:
        if (!swapwrite)
                current->flags &= ~PF_SWAPWRITE;
 
-       if (!list_empty(&failed))
-               list_splice(&failed, l);
-
        return nr_failed + retry;
 }