[RFC][PATCH -mm 1/2] mm: make shrink_all_memory overflow-resistant

["Rafael J. Wysocki" <rjw@sisk.pl>]

Make shrink_all_memory() overflow-resistant.


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 include/linux/swap.h |    2 +-
 mm/vmscan.c          |    9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

Index: linux-2.6.16-rc4-mm2/mm/vmscan.c
===================================================================
--- linux-2.6.16-rc4-mm2.orig/mm/vmscan.c
+++ linux-2.6.16-rc4-mm2/mm/vmscan.c
@@ -1785,18 +1785,19 @@ void wakeup_kswapd(struct zone *zone, in
  * Try to free `nr_pages' of memory, system-wide.  Returns the number of freed
  * pages.
  */
-int shrink_all_memory(unsigned long nr_pages)
+unsigned long shrink_all_memory(unsigned int nr_pages)
 {
 	pg_data_t *pgdat;
-	unsigned long nr_to_free = nr_pages;
-	int ret = 0;
+	long long nr_to_free = nr_pages;
+	unsigned long ret = 0;
 	struct reclaim_state reclaim_state = {
 		.reclaimed_slab = 0,
 	};
 
 	current->reclaim_state = &reclaim_state;
 	for_each_pgdat(pgdat) {
-		int freed;
+		unsigned long freed;
+
 		freed = balance_pgdat(pgdat, nr_to_free, 0);
 		ret += freed;
 		nr_to_free -= freed;
Index: linux-2.6.16-rc4-mm2/include/linux/swap.h
===================================================================
--- linux-2.6.16-rc4-mm2.orig/include/linux/swap.h
+++ linux-2.6.16-rc4-mm2/include/linux/swap.h
@@ -173,7 +173,7 @@ extern void swap_setup(void);
 
 /* linux/mm/vmscan.c */
 extern unsigned long try_to_free_pages(struct zone **, gfp_t);
-extern int shrink_all_memory(unsigned long nr_pages);
+extern unsigned long shrink_all_memory(unsigned int nr_pages);
 extern int vm_swappiness;
 
 #ifdef CONFIG_NUMA