[PATCH 09/20] Calculate the preferred zone for allocation only once

Mel Gorman
2009-02-22T23:19:47Z

get_page_from_freelist() can be called multiple times for an allocation.
Part of this calculates the preferred_zone which is the first usable
zone in the zonelist. This patch calculates preferred_zone once.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
mm/page_alloc.c | 53 ++++++++++++++++++++++++++++++++---------------------
1 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index eaa0ab7..bd7b2c6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1395,24 +1395,19 @@ static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
*/
static struct page *
get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
- struct zonelist *zonelist, int high_zoneidx, int alloc_flags)
+ struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
+ struct zone *preferred_zone)
{
struct zoneref *z;
struct page *page = NULL;
int classzone_idx;
- struct zone *zone, *preferred_zone;
+ struct zone *zone;
nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
int zlc_active = 0; /* set if using zonelist_cache */
int did_zlc_setup = 0; /* just call zlc_setup() one time */
int alloc_cpuset = 0;

- (void)first_zones_zonelist(zonelist, high_zoneidx, nodemask,
- &preferred_zone);
- if (!preferred_zone)
- return NULL;
-
classzone_idx = zone_idx(preferred_zone);
-
VM_BUG_ON(order >= MAX_ORDER);

#ifdef CONFIG_CPUSETS
@@ -1513,7 +1508,7 @@ should_alloc_retry(gfp_t gfp_mask, unsigned int order,
struct page *
__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
- nodemask_t *nodemask)
+ nodemask_t *nodemask, struct zone *preferred_zone)
{
struct page *page;

@@ -1530,7 +1525,8 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
*/
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
order, zonelist, high_zoneidx,
- ALLOC_WMARK_HIGH|ALLOC_CPUSET);
+ ALLOC_WMARK_HIGH|ALLOC_CPUSET,
+ preferred_zone);
if (page)
goto out;

@@ -1550,7 +1546,8 @@ out:
struct page *
__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
- nodemask_t *nodemask, int alloc_flags, unsigned long *did_some_progress)
+ nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
+ unsigned long *did_some_progress)
{
struct page *page = NULL;
struct reclaim_state reclaim_state;
@@ -1581,7 +1578,8 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,

if (likely(*did_some_progress))
page = get_page_from_freelist(gfp_mask, nodemask, order,
- zonelist, high_zoneidx, alloc_flags);
+ zonelist, high_zoneidx,
+ alloc_flags, preferred_zone);
return page;
}

@@ -1602,13 +1600,14 @@ static inline int is_allocation_high_priority(struct task_struct *p,
struct page *
__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
- nodemask_t *nodemask)
+ nodemask_t *nodemask, struct zone *preferred_zone)
{
struct page *page;

do {
page = get_page_from_freelist(gfp_mask, nodemask, order,
- zonelist, high_zoneidx, ALLOC_NO_WATERMARKS);
+ zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
+ preferred_zone);

if (!page && gfp_mask & __GFP_NOFAIL)
congestion_wait(WRITE, HZ/50);
@@ -1630,7 +1629,7 @@ void wake_all_kswapd(unsigned int order, struct zonelist *zonelist, enum zone_ty
static struct page * noinline
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, enum zone_type high_zoneidx,
- nodemask_t *nodemask)
+ nodemask_t *nodemask, struct zone *preferred_zone)
{
const gfp_t wait = gfp_mask & __GFP_WAIT;
struct page *page = NULL;
@@ -1680,14 +1679,15 @@ restart:
* See also cpuset_zone_allowed() comment in kernel/cpuset.c.
*/
page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
- high_zoneidx, alloc_flags);
+ high_zoneidx, alloc_flags,
+ preferred_zone);
if (page)
goto got_pg;

/* Allocate without watermarks if the context allows */
if (is_allocation_high_priority(p, gfp_mask))
page = __alloc_pages_high_priority(gfp_mask, order,
- zonelist, high_zoneidx, nodemask);
+ zonelist, high_zoneidx, nodemask, preferred_zone);
if (page)
goto got_pg;

@@ -1699,7 +1699,8 @@ restart:
page = __alloc_pages_direct_reclaim(gfp_mask, order,
zonelist, high_zoneidx,
nodemask,
- alloc_flags, &did_some_progress);
+ alloc_flags, preferred_zone,
+ &did_some_progress);
if (page)
goto got_pg;

@@ -1711,7 +1712,7 @@ restart:
if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
page = __alloc_pages_may_oom(gfp_mask, order,
zonelist, high_zoneidx,
- nodemask);
+ nodemask, preferred_zone);
if (page)
goto got_pg;

@@ -1748,6 +1749,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, nodemask_t *nodemask)
{
enum zone_type high_zoneidx = gfp_zone(gfp_mask);
+ struct zone *preferred_zone;
struct page *page;

might_sleep_if(gfp_mask & __GFP_WAIT);
@@ -1763,11 +1765,20 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
if (unlikely(!zonelist->_zonerefs->zone))
return NULL;

+ /* The preferred zone is used for statistics later */
+ (void)first_zones_zonelist(zonelist, high_zoneidx, nodemask,
+ &preferred_zone);
+ if (!preferred_zone)
+ return NULL;
+
+ /* First allocation attempt */
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
- zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET);
+ zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
+ preferred_zone);
if (unlikely(!page))
page = __alloc_pages_slowpath(gfp_mask, order,
- zonelist, high_zoneidx, nodemask);
+ zonelist, high_zoneidx, nodemask,
+ preferred_zone);

return page;
}
--
1.5.6.5