mm: don't vmalloc a huge page_to_node array for do_pages_stat()
do_pages_stat() does not need any page_to_node entry for real. Just pass
the pointers to the user-space page address array and to the user-space
status array, and have do_pages_stat() traverse the former and fill the
latter directly.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/migrate.c b/mm/migrate.c
index f233519..a4c2908 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -906,25 +906,33 @@
}
/*
- * Determine the nodes of a list of pages. The addr in the pm array
- * must have been set to the virtual address of which we want to determine
- * the node number.
+ * Determine the nodes of an array of pages and store it in an array of status.
*/
-static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm)
+static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
+ const void __user * __user *pages,
+ int __user *status)
{
+ unsigned long i;
+ int err;
+
down_read(&mm->mmap_sem);
- for ( ; pm->node != MAX_NUMNODES; pm++) {
+ for (i = 0; i < nr_pages; i++) {
+ const void __user *p;
+ unsigned long addr;
struct vm_area_struct *vma;
struct page *page;
- int err;
err = -EFAULT;
- vma = find_vma(mm, pm->addr);
+ if (get_user(p, pages+i))
+ goto out;
+ addr = (unsigned long) p;
+
+ vma = find_vma(mm, addr);
if (!vma)
goto set_status;
- page = follow_page(vma, pm->addr, 0);
+ page = follow_page(vma, addr, 0);
err = PTR_ERR(page);
if (IS_ERR(page))
@@ -937,11 +945,13 @@
err = page_to_nid(page);
set_status:
- pm->status = err;
+ put_user(err, status+i);
}
+ err = 0;
+out:
up_read(&mm->mmap_sem);
- return 0;
+ return err;
}
/*
@@ -997,6 +1007,10 @@
if (err)
goto out2;
+ if (!nodes) {
+ err = do_pages_stat(mm, nr_pages, pages, status);
+ goto out2;
+ }
task_nodes = cpuset_mems_allowed(task);
@@ -1045,11 +1059,7 @@
/* End marker */
pm[nr_pages].node = MAX_NUMNODES;
- if (nodes)
- err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
- else
- err = do_pages_stat(mm, pm);
-
+ err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
if (err >= 0)
/* Return status information */
for (i = 0; i < nr_pages; i++)
