From 5117f45d11a9ee62d9b086f1312f3f31781ff155 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 16 Jun 2009 15:31:59 -0700 Subject: [PATCH] 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 Reviewed-by: KOSAKI Motohiro Reviewed-by: Pekka Enberg Cc: Christoph Lameter Cc: Peter Zijlstra Cc: Nick Piggin Cc: Dave Hansen Cc: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 54 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 22 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b098596..8fc6d1f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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; } -- 2.7.4