[V4,1/2] mm/hugetlb: Make alloc_gigantic_page() available for general use

Commit Message

Anshuman Khandual Oct. 7, 2019, 5:45 a.m. UTC

alloc_gigantic_page() implements an allocation method where it scans over
various zones looking for a large contiguous memory block which could not
have been allocated through the buddy allocator. A subsequent patch which
tests arch page table helpers needs such a method to allocate PUD_SIZE
sized memory block. In the future such methods might have other use cases
as well. So alloc_gigantic_page() has been split carving out actual memory
allocation method and made available via new alloc_gigantic_page_order().

Cc: Andrew Morton <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Mark Brown <[e-mail]>
Cc: Steven Price <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: Tetsuo Handa <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Sri Krishna chowdary <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Russell King - ARM Linux <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Martin Schwidefsky <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Kirill A. Shutemov <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Anshuman Khandual <[e-mail]>
---
 include/linux/hugetlb.h |  9 +++++++++
 mm/hugetlb.c            | 24 ++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

Patch

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 53fc34f930d0..cc50d5ad4885 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -299,6 +299,9 @@  static inline bool is_file_hugepages(struct file *file)
 }
 
 
+struct page *
+alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
+			  int nid, nodemask_t *nodemask);
 #else /* !CONFIG_HUGETLBFS */
 
 #define is_file_hugepages(file)			false
@@ -310,6 +313,12 @@  hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
 	return ERR_PTR(-ENOSYS);
 }
 
+static inline struct page *
+alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
+			  int nid, nodemask_t *nodemask)
+{
+	return NULL;
+}
 #endif /* !CONFIG_HUGETLBFS */
 
 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ef37c85423a5..3fb81252f52b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1112,10 +1112,9 @@  static bool zone_spans_last_pfn(const struct zone *zone,
 	return zone_spans_pfn(zone, last_pfn);
 }
 
-static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
+struct page *alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
 		int nid, nodemask_t *nodemask)
 {
-	unsigned int order = huge_page_order(h);
 	unsigned long nr_pages = 1 << order;
 	unsigned long ret, pfn, flags;
 	struct zonelist *zonelist;
@@ -1151,6 +1150,14 @@  static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
 	return NULL;
 }
 
+static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
+					int nid, nodemask_t *nodemask)
+{
+	unsigned int order = huge_page_order(h);
+
+	return alloc_gigantic_page_order(order, gfp_mask, nid, nodemask);
+}
+
 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
 static void prep_compound_gigantic_page(struct page *page, unsigned int order);
 #else /* !CONFIG_CONTIG_ALLOC */
@@ -1159,6 +1166,12 @@  static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
 {
 	return NULL;
 }
+
+struct page *alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
+				       int nid, nodemask_t *nodemask)
+{
+	return NULL;
+}
 #endif /* CONFIG_CONTIG_ALLOC */
 
 #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
@@ -1167,6 +1180,13 @@  static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
 {
 	return NULL;
 }
+
+struct page *alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
+				       int nid, nodemask_t *nodemask)
+{
+	return NULL;
+}
+
 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
 static inline void destroy_compound_gigantic_page(struct page *page,
 						unsigned int order) { }