[PATCH] mempolicies: private pointer in check_range and MPOL_MF_INVERT

This was was first posted at
http://marc.theaimsgroup.com/?l=linux-mm&m=113149240227584&w=2

(Part of this functionality is also contained in the direct migration
pathset. The functionality here is more generic and independent of that
patchset.)

- Add internal flags MPOL_MF_INVERT to control check_range() behavior.

- Replace the pagelist passed through by check_range by a general
  private pointer that may be used for other purposes.
  (The following patches will use that to merge numa_maps into
  mempolicy.c and to better group the page migration code in
  the policy layer)

- Improve some comments.

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, 24 insertions, 22 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 30bdafba52d8..270e9a39ec15 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -88,8 +88,9 @@
 #include <asm/tlbflush.h>
 #include <asm/uaccess.h>
 
-/* Internal MPOL_MF_xxx flags */
+/* Internal flags */
 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0)    /* Skip checks for continuous vmas */
+#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1)          /* Invert check for nodemask */
 
 static kmem_cache_t *policy_cache;
 static kmem_cache_t *sn_cache;
@@ -227,11 +228,11 @@ static void migrate_page_add(struct vm_area_struct *vma,
         }
 }
 
-/* Ensure all existing pages follow the policy. */
+/* Scan through pages checking if pages follow certain conditions. */
 static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                 unsigned long addr, unsigned long end,
                 const nodemask_t *nodes, unsigned long flags,
-                struct list_head *pagelist)
+                void *private)
 {
         pte_t *orig_pte;
         pte_t *pte;
@@ -248,12 +249,13 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                 if (!page)
                         continue;
                 nid = page_to_nid(page);
-                if (!node_isset(nid, *nodes)) {
-                        if (pagelist)
-                                migrate_page_add(vma, page, pagelist, flags);
-                        else
-                                break;
-                }
+                if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
+                        continue;
+
+                if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+                        migrate_page_add(vma, page, private, flags);
+                else
+                        break;
         } while (pte++, addr += PAGE_SIZE, addr != end);
         pte_unmap_unlock(orig_pte, ptl);
         return addr != end;
@@ -262,7 +264,7 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                 unsigned long addr, unsigned long end,
                 const nodemask_t *nodes, unsigned long flags,
-                struct list_head *pagelist)
+                void *private)
 {
         pmd_t *pmd;
         unsigned long next;
@@ -273,7 +275,7 @@ static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                 if (pmd_none_or_clear_bad(pmd))
                         continue;
                 if (check_pte_range(vma, pmd, addr, next, nodes,
-                                    flags, pagelist))
+                                    flags, private))
                         return -EIO;
         } while (pmd++, addr = next, addr != end);
         return 0;
@@ -282,7 +284,7 @@ static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
 static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
                 unsigned long addr, unsigned long end,
                 const nodemask_t *nodes, unsigned long flags,
-                struct list_head *pagelist)
+                void *private)
 {
         pud_t *pud;
         unsigned long next;
@@ -293,7 +295,7 @@ static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
                 if (pud_none_or_clear_bad(pud))
                         continue;
                 if (check_pmd_range(vma, pud, addr, next, nodes,
-                                    flags, pagelist))
+                                    flags, private))
                         return -EIO;
         } while (pud++, addr = next, addr != end);
         return 0;
@@ -302,7 +304,7 @@ static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
 static inline int check_pgd_range(struct vm_area_struct *vma,
                 unsigned long addr, unsigned long end,
                 const nodemask_t *nodes, unsigned long flags,
-                struct list_head *pagelist)
+                void *private)
 {
         pgd_t *pgd;
         unsigned long next;
@@ -313,7 +315,7 @@ static inline int check_pgd_range(struct vm_area_struct *vma,
                 if (pgd_none_or_clear_bad(pgd))
                         continue;
                 if (check_pud_range(vma, pgd, addr, next, nodes,
-                                    flags, pagelist))
+                                    flags, private))
                         return -EIO;
         } while (pgd++, addr = next, addr != end);
         return 0;
@@ -335,8 +337,7 @@ static inline int vma_migratable(struct vm_area_struct *vma)
  */
 static struct vm_area_struct *
 check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
-                const nodemask_t *nodes, unsigned long flags,
-                struct list_head *pagelist)
+                const nodemask_t *nodes, unsigned long flags, void *private)
 {
         int err;
         struct vm_area_struct *first, *vma, *prev;
@@ -363,7 +364,7 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
                         if (vma->vm_start > start)
                                 start = vma->vm_start;
                         err = check_pgd_range(vma, start, endvma, nodes,
-                                                flags, pagelist);
+                                                flags, private);
                         if (err) {
                                 first = ERR_PTR(err);
                                 break;
@@ -452,7 +453,8 @@ long do_mbind(unsigned long start, unsigned long len,
         int err;
         LIST_HEAD(pagelist);
 
-        if ((flags & ~(unsigned long)(MPOL_MF_STRICT|MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
+        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))
@@ -490,8 +492,9 @@ long do_mbind(unsigned long start, unsigned long len,
                         mode,nodes_addr(nodes)[0]);
 
         down_write(&mm->mmap_sem);
-        vma = check_range(mm, start, end, nmask, flags,
-              (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) ? &pagelist : NULL);
+        vma = check_range(mm, start, end, nmask,
+                          flags | MPOL_MF_INVERT, &pagelist);
+
         err = PTR_ERR(vma);
         if (!IS_ERR(vma)) {
                 int nr_failed = 0;
@@ -646,7 +649,6 @@ int do_migrate_pages(struct mm_struct *mm,
         nodemask_t nodes;
 
         nodes_andnot(nodes, *from_nodes, *to_nodes);
-        nodes_complement(nodes, nodes);
 
         down_read(&mm->mmap_sem);
         check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nodes,