[PATCH v3 4/6] mm/thp: add THP allocation helper

Ralph Campbell
2020-11-06T00:52:09Z

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 c603237e006c..242398c4b556 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -564,6 +564,16 @@ static inline struct page *alloc_pages(gfp_t gfp_mask, unsigned int order)
#define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
#define alloc_page_vma(gfp_mask, vma, addr) \
alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), 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

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 a073e66d0ee2..c2c1d3e7c35f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -765,6 +765,20 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
return __do_huge_pmd_anonymous_page(vmf, page, gfp);
}

+struct page *alloc_transhugepage(struct vm_area_struct *vma,
+ unsigned long haddr)
+{
+ gfp_t gfp;
+ struct page *page;
+
+ gfp = alloc_hugepage_direct_gfpmask(vma);
+ page = 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)
--
2.20.1