On 19 Jun 2020, at 17:56, Ralph Campbell wrote:
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 | 16 ++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 67a0774e080b..1c7d968a27d3 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, int 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_ARCH_ENABLE_THP_MIGRATION +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 25d95f7b1e98..f749633ed350 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -775,6 +775,22 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) return __do_huge_pmd_anonymous_page(vmf, page, gfp); }
+#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION +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); +#endif
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
Why use CONFIG_ARCH_ENABLE_THP_MIGRATION to guard THP allocator helper? Shouldn’t CONFIG_TRANSPARENT_HUGEPAGE be used? Also the helper still allocates a THP even if transparent_hugepage_enabled(vma) is false, which is wrong, right?
-- Best Regards, Yan Zi