mm: rework do_pages_move() to work on page_sized chunks
Rework do_pages_move() to work by page-sized chunks of struct page_to_node
that are passed to do_move_page_to_node_array(). We now only have to
allocate a single page instead a possibly very large vmalloc area to store
all page_to_node entries.
As a result, new_page_node() will now have a very small lookup, hidding
much of the overall sys_move_pages() overhead.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Nathalie Furmento <Nathalie.Furmento@labri.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 21631ab..0a75716 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -919,41 +919,43 @@
const int __user *nodes,
int __user *status, int flags)
{
- struct page_to_node *pm = NULL;
+ struct page_to_node *pm;
nodemask_t task_nodes;
- int err = 0;
- int i;
+ unsigned long chunk_nr_pages;
+ unsigned long chunk_start;
+ int err;
task_nodes = cpuset_mems_allowed(task);
- /* Limit nr_pages so that the multiplication may not overflow */
- if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
- err = -E2BIG;
+ err = -ENOMEM;
+ pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
+ if (!pm)
goto out;
- }
-
- pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
- if (!pm) {
- err = -ENOMEM;
- goto out;
- }
-
/*
- * Get parameters from user space and initialize the pm
- * array. Return various errors if the user did something wrong.
+ * Store a chunk of page_to_node array in a page,
+ * but keep the last one as a marker
*/
- for (i = 0; i < nr_pages; i++) {
- const void __user *p;
+ chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1;
- err = -EFAULT;
- if (get_user(p, pages + i))
- goto out_pm;
+ for (chunk_start = 0;
+ chunk_start < nr_pages;
+ chunk_start += chunk_nr_pages) {
+ int j;
- pm[i].addr = (unsigned long)p;
- if (nodes) {
+ if (chunk_start + chunk_nr_pages > nr_pages)
+ chunk_nr_pages = nr_pages - chunk_start;
+
+ /* fill the chunk pm with addrs and nodes from user-space */
+ for (j = 0; j < chunk_nr_pages; j++) {
+ const void __user *p;
int node;
- if (get_user(node, nodes + i))
+ err = -EFAULT;
+ if (get_user(p, pages + j + chunk_start))
+ goto out_pm;
+ pm[j].addr = (unsigned long) p;
+
+ if (get_user(node, nodes + j + chunk_start))
goto out_pm;
err = -ENODEV;
@@ -964,22 +966,29 @@
if (!node_isset(node, task_nodes))
goto out_pm;
- pm[i].node = node;
- } else
- pm[i].node = 0; /* anything to not match MAX_NUMNODES */
- }
- /* End marker */
- pm[nr_pages].node = MAX_NUMNODES;
+ pm[j].node = node;
+ }
- err = do_move_page_to_node_array(mm, pm, flags & MPOL_MF_MOVE_ALL);
- if (err >= 0)
+ /* End marker for this chunk */
+ pm[chunk_nr_pages].node = MAX_NUMNODES;
+
+ /* Migrate this chunk */
+ err = do_move_page_to_node_array(mm, pm,
+ flags & MPOL_MF_MOVE_ALL);
+ if (err < 0)
+ goto out_pm;
+
/* Return status information */
- for (i = 0; i < nr_pages; i++)
- if (put_user(pm[i].status, status + i))
+ for (j = 0; j < chunk_nr_pages; j++)
+ if (put_user(pm[j].status, status + j + chunk_start)) {
err = -EFAULT;
+ goto out_pm;
+ }
+ }
+ err = 0;
out_pm:
- vfree(pm);
+ free_page((unsigned long)pm);
out:
return err;
}