[PATCH 3.14 54/77] mm: page_alloc: use unsigned int for order in more places

From: Greg Kroah-Hartman
Date: Tue Jan 27 2015 - 20:52:48 EST


3.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mel Gorman <mgorman@xxxxxxx>

commit 7aeb09f9104b760fc53c98cb7d20d06640baf9e6 upstream.

X86 prefers the use of unsigned types for iterators and there is a
tendency to mix whether a signed or unsigned type if used for page order.
This converts a number of sites in mm/page_alloc.c to use unsigned int for
order where possible.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
include/linux/mmzone.h | 8 ++++----
mm/page_alloc.c | 43 +++++++++++++++++++++++--------------------
2 files changed, 27 insertions(+), 24 deletions(-)

--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -807,10 +807,10 @@ static inline bool pgdat_is_empty(pg_dat
extern struct mutex zonelists_mutex;
void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx);
-bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
- int classzone_idx, int alloc_flags);
-bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
- int classzone_idx, int alloc_flags);
+bool zone_watermark_ok(struct zone *z, unsigned int order,
+ unsigned long mark, int classzone_idx, int alloc_flags);
+bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
+ unsigned long mark, int classzone_idx, int alloc_flags);
enum memmap_context {
MEMMAP_EARLY,
MEMMAP_HOTPLUG,
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -408,7 +408,8 @@ static int destroy_compound_page(struct
return bad;
}

-static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
+static inline void prep_zero_page(struct page *page, unsigned int order,
+ gfp_t gfp_flags)
{
int i;

@@ -452,7 +453,7 @@ static inline void set_page_guard_flag(s
static inline void clear_page_guard_flag(struct page *page) { }
#endif

-static inline void set_page_order(struct page *page, int order)
+static inline void set_page_order(struct page *page, unsigned int order)
{
set_page_private(page, order);
__SetPageBuddy(page);
@@ -503,7 +504,7 @@ __find_buddy_index(unsigned long page_id
* For recording page's order, we use page_private(page).
*/
static inline int page_is_buddy(struct page *page, struct page *buddy,
- int order)
+ unsigned int order)
{
if (!pfn_valid_within(page_to_pfn(buddy)))
return 0;
@@ -722,7 +723,7 @@ static void free_pcppages_bulk(struct zo
spin_unlock(&zone->lock);
}

-static void free_one_page(struct zone *zone, struct page *page, int order,
+static void free_one_page(struct zone *zone, struct page *page, unsigned int order,
int migratetype)
{
spin_lock(&zone->lock);
@@ -904,7 +905,7 @@ static inline int check_new_page(struct
return 0;
}

-static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
+static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags)
{
int i;

@@ -1115,16 +1116,17 @@ static int try_to_steal_freepages(struct

/* Remove an element from the buddy allocator from the fallback list */
static inline struct page *
-__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
+__rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
{
struct free_area *area;
- int current_order;
+ unsigned int current_order;
struct page *page;
int migratetype, new_type, i;

/* Find the largest possible block of pages in the other list */
- for (current_order = MAX_ORDER-1; current_order >= order;
- --current_order) {
+ for (current_order = MAX_ORDER-1;
+ current_order >= order && current_order <= MAX_ORDER-1;
+ --current_order) {
for (i = 0;; i++) {
migratetype = fallbacks[start_migratetype][i];

@@ -1352,7 +1354,7 @@ void mark_free_pages(struct zone *zone)
{
unsigned long pfn, max_zone_pfn;
unsigned long flags;
- int order, t;
+ unsigned int order, t;
struct list_head *curr;

if (zone_is_empty(zone))
@@ -1547,8 +1549,8 @@ int split_free_page(struct page *page)
*/
static inline
struct page *buffered_rmqueue(struct zone *preferred_zone,
- struct zone *zone, int order, gfp_t gfp_flags,
- int migratetype)
+ struct zone *zone, unsigned int order,
+ gfp_t gfp_flags, int migratetype)
{
unsigned long flags;
struct page *page;
@@ -1697,8 +1699,9 @@ static inline bool should_fail_alloc_pag
* Return true if free pages are above 'mark'. This takes into account the order
* of the allocation.
*/
-static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
- int classzone_idx, int alloc_flags, long free_pages)
+static bool __zone_watermark_ok(struct zone *z, unsigned int order,
+ unsigned long mark, int classzone_idx, int alloc_flags,
+ long free_pages)
{
/* free_pages my go negative - that's OK */
long min = mark;
@@ -1732,15 +1735,15 @@ static bool __zone_watermark_ok(struct z
return true;
}

-bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
+bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
int classzone_idx, int alloc_flags)
{
return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
zone_page_state(z, NR_FREE_PAGES));
}

-bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
- int classzone_idx, int alloc_flags)
+bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
+ unsigned long mark, int classzone_idx, int alloc_flags)
{
long free_pages = zone_page_state(z, NR_FREE_PAGES);

@@ -4137,7 +4140,7 @@ void __meminit memmap_init_zone(unsigned

static void __meminit zone_init_free_lists(struct zone *zone)
{
- int order, t;
+ unsigned int order, t;
for_each_migratetype_order(order, t) {
INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
zone->free_area[order].nr_free = 0;
@@ -6477,7 +6480,7 @@ __offline_isolated_pages(unsigned long s
{
struct page *page;
struct zone *zone;
- int order, i;
+ unsigned int order, i;
unsigned long pfn;
unsigned long flags;
/* find the first valid pfn */
@@ -6529,7 +6532,7 @@ bool is_free_buddy_page(struct page *pag
struct zone *zone = page_zone(page);
unsigned long pfn = page_to_pfn(page);
unsigned long flags;
- int order;
+ unsigned int order;

spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {


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