diff mbox series

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

Message ID 20201106005147.20113-5-rcampbell@nvidia.com (mailing list archive)
State New
Headers show
Series mm/hmm/nouveau: add THP migration to migrate_vma_* | expand

Commit Message

Ralph Campbell Nov. 6, 2020, 12:51 a.m. UTC
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(+)

Comments

Christoph Hellwig Nov. 6, 2020, 8:01 a.m. UTC | #1
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +extern struct page *alloc_transhugepage(struct vm_area_struct *vma,
> +					unsigned long addr);

No need for the extern.  And also here: do we actually need the stub,
or can the caller make sure (using IS_ENABLED and similar) that the
compiler knows the code is dead?

> +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;

I think do_huge_pmd_anonymous_page should be switched to use this
helper as well.
Ralph Campbell Nov. 6, 2020, 9:09 p.m. UTC | #2
On 11/6/20 12:01 AM, Christoph Hellwig wrote:
>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> +extern struct page *alloc_transhugepage(struct vm_area_struct *vma,
>> +					unsigned long addr);
> 
> No need for the extern.  And also here: do we actually need the stub,
> or can the caller make sure (using IS_ENABLED and similar) that the
> compiler knows the code is dead?

Same problem as with prep_transhuge_device_private_page(), since
alloc_hugepage_direct_gfpmask() and alloc_hugepage_vma() are not
EXPORT_SYMBOL_GPL.

>> +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;
> 
> I think do_huge_pmd_anonymous_page should be switched to use this
> helper as well.

Sure, I'll do that for v4.
diff mbox series

Patch

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)