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From:   Ralph Campbell <rcampbell@nvidia.com>
To:     <linux-mm@kvack.org>, <nouveau@lists.freedesktop.org>,
        <linux-kselftest@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     Jerome Glisse <jglisse@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Alistair Popple <apopple@nvidia.com>,
        Christoph Hellwig <hch@lst.de>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Bharata B Rao <bharata@linux.ibm.com>,
        Ben Skeggs <bskeggs@redhat.com>, Shuah Khan <shuah@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ralph Campbell <rcampbell@nvidia.com>
Subject: [PATCH v2 5/7] mm/thp: add THP allocation helper
Date:   Wed, 2 Sep 2020 09:58:28 -0700
Message-ID: <20200902165830.5367-6-rcampbell@nvidia.com>
In-Reply-To: <20200902165830.5367-1-rcampbell@nvidia.com>
References: <20200902165830.5367-1-rcampbell@nvidia.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Transparent huge page allocation policy is controlled by several sysfs
variables. Rather than expose these to each device driver that needs to
allocate THPs, provide a helper function.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
---
 include/linux/gfp.h | 10 ++++++++++
 mm/huge_memory.c    | 14 ++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 67a0774e080b..6faf4ea5501b 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -562,6 +562,16 @@ extern struct page *alloc_pages_vma(gfp_t gfp_mask, in=
t order,
 	alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), false)
 #define alloc_page_vma_node(gfp_mask, vma, addr, node)		\
 	alloc_pages_vma(gfp_mask, 0, vma, addr, node, false)
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern struct page *alloc_transhugepage(struct vm_area_struct *vma,
+					unsigned long addr);
+#else
+static inline struct page *alloc_transhugepage(struct vm_area_struct *vma,
+						unsigned long addr)
+{
+	return NULL;
+}
+#endif
=20
 extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order);
 extern unsigned long get_zeroed_page(gfp_t gfp_mask);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1e848cc0c3dc..e4e1fe199dc1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -764,6 +764,20 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault =
*vmf)
 	return __do_huge_pmd_anonymous_page(vmf, page, gfp);
 }
=20
+struct page *alloc_transhugepage(struct vm_area_struct *vma,
+				 unsigned long haddr)
+{
+	gfp_t gfp;
+	struct page *page;
+
+	gfp =3D alloc_hugepage_direct_gfpmask(vma);
+	page =3D alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
+	if (page)
+		prep_transhuge_page(page);
+	return page;
+}
+EXPORT_SYMBOL_GPL(alloc_transhugepage);
+
 static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 		pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write,
 		pgtable_t pgtable)
--=20
2.20.1