[PATCH V5 1/2] mm/hugetlb: Make alloc_gigantic_page() available for general use

From: Anshuman Khandual <hidden>
Date: 2019-10-11 06:25:51
Also in: linux-arm-kernel, linux-mips, linux-mm, linux-s390, linux-sh, lkml, sparclinux
Subsystem: hugetlb subsystem, memory management, the rest · Maintainers: Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds

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 <akpm@linux-foundation.org>
Cc: Vlastimil Babka <redacted>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <redacted>
Cc: Mike Rapoport <redacted>
Cc: Mike Kravetz <redacted>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <redacted>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Steven Price <Steven.Price@arm.com>
Cc: Ard Biesheuvel <redacted>
Cc: Masahiro Yamada <redacted>
Cc: Kees Cook <redacted>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sri Krishna chowdary <redacted>
Cc: Dave Hansen <redacted>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <redacted>
Cc: Martin Schwidefsky <redacted>
Cc: Heiko Carstens <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Vineet Gupta <redacted>
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <redacted>
Cc: Ralf Baechle <redacted>
Cc: Kirill A. Shutemov <redacted>
Cc: Gerald Schaefer <redacted>
Cc: Christophe Leroy <redacted>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
 include/linux/hugetlb.h |  9 +++++++++
 mm/hugetlb.c            | 24 ++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 4c5a16b..7ff1e36 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h

@@ -298,6 +298,9 @@ 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

@@ -309,6 +312,12 @@ 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 977f9a3..2996e44 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c

@@ -1066,10 +1066,9 @@ 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;

@@ -1105,6 +1104,14 @@ 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 */

@@ -1113,6 +1120,12 @@ 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 */

@@ -1121,6 +1134,13 @@ 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) { }

-- 
2.7.4

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