[RFC PATCH 3/3] mm/hugetlb: use find_alloc_contig_pages() to allocate gigantic pages

From: Mike Kravetz
Date: Mon Feb 12 2018 - 17:23:57 EST


Use the new find_alloc_contig_pages() interface for the allocation of
gigantic pages.

Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
mm/hugetlb.c | 88 +++++-------------------------------------------------------
1 file changed, 6 insertions(+), 82 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9a334f5fb730..4c0c4f86dcda 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1060,92 +1060,16 @@ static void destroy_compound_gigantic_page(struct page *page,
__ClearPageHead(page);
}

-static void free_gigantic_page(struct page *page, unsigned int order)
+static void free_gigantic_page(struct page *page, struct hstate *h)
{
- free_contig_range(page_to_pfn(page), 1 << order);
-}
-
-static int __alloc_gigantic_page(unsigned long start_pfn,
- unsigned long nr_pages, gfp_t gfp_mask)
-{
- unsigned long end_pfn = start_pfn + nr_pages;
- return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
- gfp_mask);
-}
-
-static bool pfn_range_valid_gigantic(struct zone *z,
- unsigned long start_pfn, unsigned long nr_pages)
-{
- unsigned long i, end_pfn = start_pfn + nr_pages;
- struct page *page;
-
- for (i = start_pfn; i < end_pfn; i++) {
- if (!pfn_valid(i))
- return false;
-
- page = pfn_to_page(i);
-
- if (page_zone(page) != z)
- return false;
-
- if (PageReserved(page))
- return false;
-
- if (page_count(page) > 0)
- return false;
-
- if (PageHuge(page))
- return false;
- }
-
- return true;
-}
-
-static bool zone_spans_last_pfn(const struct zone *zone,
- unsigned long start_pfn, unsigned long nr_pages)
-{
- unsigned long last_pfn = start_pfn + nr_pages - 1;
- return zone_spans_pfn(zone, last_pfn);
+ free_contig_pages(page, pages_per_huge_page(h));
}

static struct page *alloc_gigantic_page(int nid, struct hstate *h)
{
- unsigned int order = huge_page_order(h);
- unsigned long nr_pages = 1 << order;
- unsigned long ret, pfn, flags;
- struct zonelist *zonelist;
- struct zone *zone;
- struct zoneref *z;
- gfp_t gfp_mask;
-
- gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
- zonelist = node_zonelist(nid, gfp_mask);
- for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), NULL) {
- spin_lock_irqsave(&zone->lock, flags);
+ gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;

- pfn = ALIGN(zone->zone_start_pfn, nr_pages);
- while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
- if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) {
- /*
- * We release the zone lock here because
- * alloc_contig_range() will also lock the zone
- * at some point. If there's an allocation
- * spinning on this lock, it may win the race
- * and cause alloc_contig_range() to fail...
- */
- spin_unlock_irqrestore(&zone->lock, flags);
- ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask);
- if (!ret)
- return pfn_to_page(pfn);
- spin_lock_irqsave(&zone->lock, flags);
- }
- pfn += nr_pages;
- }
-
- spin_unlock_irqrestore(&zone->lock, flags);
- }
-
- return NULL;
+ return find_alloc_contig_pages(huge_page_order(h), gfp_mask, nid, NULL);
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
@@ -1181,7 +1105,7 @@ static int alloc_fresh_gigantic_page(struct hstate *h,

#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
static inline bool gigantic_page_supported(void) { return false; }
-static inline void free_gigantic_page(struct page *page, unsigned int order) { }
+static void free_gigantic_page(struct page *page, struct hstate *h) { }
static inline void destroy_compound_gigantic_page(struct page *page,
unsigned int order) { }
static inline int alloc_fresh_gigantic_page(struct hstate *h,
@@ -1208,7 +1132,7 @@ static void update_and_free_page(struct hstate *h, struct page *page)
set_page_refcounted(page);
if (hstate_is_gigantic(h)) {
destroy_compound_gigantic_page(page, huge_page_order(h));
- free_gigantic_page(page, huge_page_order(h));
+ free_gigantic_page(page, h);
} else {
__free_pages(page, huge_page_order(h));
}
--
2.13.6