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page allocator: calculate the preferred zone for allocation only once 

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 but the zone depends on the GFP flags specified at the
beginning of the allocation call.  This patch calculates preferred_zone
once.  It's safe to do this because if preferred_zone is NULL at the start
of the call, no amount of direct reclaim or other actions will change the
fact the allocation will fail.

[akpm@linux-foundation.org: remove (void) casts]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2009-06-16 15:31:59 -07:00 committed by Linus Torvalds
parent 49255c619f
commit 5117f45d11
1 changed files with 32 additions and 22 deletions
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54
mm/page_alloc.c
View File

@ -1388,26 +1388,21 @@ 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 */
(void)first_zones_zonelist(zonelist, high_zoneidx, nodemask,
&preferred_zone);
if (!preferred_zone)
return NULL;
classzone_idx = zone_idx(preferred_zone);
if (WARN_ON_ONCE(order >= MAX_ORDER))
return NULL;
classzone_idx = zone_idx(preferred_zone);
zonelist_scan:
/*
* Scan zonelist, looking for a zone with enough free.
@ -1500,7 +1495,7 @@ should_alloc_retry(gfp_t gfp_mask, unsigned int order,
static inline 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;
@ -1517,7 +1512,8 @@ __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;
@ -1537,7 +1533,8 @@ out:
static inline 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;
@ -1569,7 +1566,8 @@ __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;
}
@ -1589,13 +1587,14 @@ is_allocation_high_priority(struct task_struct *p, gfp_t gfp_mask)
static inline 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);
@ -1618,7 +1617,7 @@ void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
static inline struct page *
__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;
@ -1668,7 +1667,8 @@ 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;
@ -1678,7 +1678,7 @@ rebalance:
/* Do not dip into emergency reserves if specified */
if (!(gfp_mask & __GFP_NOMEMALLOC)) {
page = __alloc_pages_high_priority(gfp_mask, order,
zonelist, high_zoneidx, nodemask);
zonelist, high_zoneidx, nodemask, preferred_zone);
if (page)
goto got_pg;
}
@ -1695,7 +1695,8 @@ rebalance:
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;
@ -1707,7 +1708,7 @@ rebalance:
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;
@ -1752,6 +1753,7 @@ __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;
lockdep_trace_alloc(gfp_mask);
@ -1769,11 +1771,19 @@ __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 */
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;
}