From 9cd7555875bb09dad875e89a76f41f576e11c638 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 24 Feb 2017 14:56:29 -0800 Subject: [PATCH] mm, page_alloc: split alloc_pages_nodemask() alloc_pages_nodemask does a number of preperation steps that determine what zones can be used for the allocation depending on a variety of factors. This is fine but a hypothetical caller that wanted multiple order-0 pages has to do the preparation steps multiple times. This patch structures __alloc_pages_nodemask such that it's relatively easy to build a bulk order-0 page allocator. There is no functional change. Link: http://lkml.kernel.org/r/20170123153906.3122-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Hillf Danton Acked-by: Vlastimil Babka Cc: Jesper Dangaard Brouer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 75 +++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 46 insertions(+), 29 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 284153d..678b288 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3855,60 +3855,77 @@ got_pg: return page; } -/* - * This is the 'heart' of the zoned buddy allocator. - */ -struct page * -__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, - struct zonelist *zonelist, nodemask_t *nodemask) +static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, + struct zonelist *zonelist, nodemask_t *nodemask, + struct alloc_context *ac, gfp_t *alloc_mask, + unsigned int *alloc_flags) { - struct page *page; - unsigned int alloc_flags = ALLOC_WMARK_LOW; - gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */ - struct alloc_context ac = { - .high_zoneidx = gfp_zone(gfp_mask), - .zonelist = zonelist, - .nodemask = nodemask, - .migratetype = gfpflags_to_migratetype(gfp_mask), - }; + ac->high_zoneidx = gfp_zone(gfp_mask); + ac->zonelist = zonelist; + ac->nodemask = nodemask; + ac->migratetype = gfpflags_to_migratetype(gfp_mask); if (cpusets_enabled()) { - alloc_mask |= __GFP_HARDWALL; - alloc_flags |= ALLOC_CPUSET; - if (!ac.nodemask) - ac.nodemask = &cpuset_current_mems_allowed; + *alloc_mask |= __GFP_HARDWALL; + *alloc_flags |= ALLOC_CPUSET; + if (!ac->nodemask) + ac->nodemask = &cpuset_current_mems_allowed; } - gfp_mask &= gfp_allowed_mask; - lockdep_trace_alloc(gfp_mask); might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); if (should_fail_alloc_page(gfp_mask, order)) - return NULL; + return false; /* * Check the zones suitable for the gfp_mask contain at least one * valid zone. It's possible to have an empty zonelist as a result * of __GFP_THISNODE and a memoryless node */ - if (unlikely(!zonelist->_zonerefs->zone)) - return NULL; + if (unlikely(!ac->zonelist->_zonerefs->zone)) + return false; - if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE) - alloc_flags |= ALLOC_CMA; + if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE) + *alloc_flags |= ALLOC_CMA; + + return true; +} +/* Determine whether to spread dirty pages and what the first usable zone */ +static inline void finalise_ac(gfp_t gfp_mask, + unsigned int order, struct alloc_context *ac) +{ /* Dirty zone balancing only done in the fast path */ - ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE); + ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE); /* * The preferred zone is used for statistics but crucially it is * also used as the starting point for the zonelist iterator. It * may get reset for allocations that ignore memory policies. */ - ac.preferred_zoneref = first_zones_zonelist(ac.zonelist, - ac.high_zoneidx, ac.nodemask); + ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, + ac->high_zoneidx, ac->nodemask); +} + +/* + * This is the 'heart' of the zoned buddy allocator. + */ +struct page * +__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, + struct zonelist *zonelist, nodemask_t *nodemask) +{ + struct page *page; + unsigned int alloc_flags = ALLOC_WMARK_LOW; + gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */ + struct alloc_context ac = { }; + + gfp_mask &= gfp_allowed_mask; + if (!prepare_alloc_pages(gfp_mask, order, zonelist, nodemask, &ac, &alloc_mask, &alloc_flags)) + return NULL; + + finalise_ac(gfp_mask, order, &ac); if (!ac.preferred_zoneref->zone) { page = NULL; /* -- 2.7.4