Re: [PATCH v4 04/36] mm: Introduce thp_size

David Hildenbrand
2020-05-15T13:38:56Z

On 15.05.20 15:16, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> This is like page_size(), but compiles down to just PAGE_SIZE if THP
> are disabled. Convert the users of hpage_nr_pages() which would prefer
> this interface.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> drivers/nvdimm/btt.c | 4 +---
> drivers/nvdimm/pmem.c | 6 ++----
> include/linux/huge_mm.h | 7 +++++++
> mm/internal.h | 2 +-
> mm/page_io.c | 2 +-
> mm/page_vma_mapped.c | 4 ++--
> 6 files changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index 3b09419218d6..78e8d972d45a 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -1488,10 +1488,8 @@ static int btt_rw_page(struct block_device *bdev, sector_t sector,
> {
> struct btt *btt = bdev->bd_disk->private_data;
> int rc;
> - unsigned int len;
>
> - len = hpage_nr_pages(page) * PAGE_SIZE;
> - rc = btt_do_bvec(btt, NULL, page, len, 0, op, sector);
> + rc = btt_do_bvec(btt, NULL, page, thp_size(page), 0, op, sector);
> if (rc == 0)
> page_endio(page, op_is_write(op), 0);
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 2df6994acf83..d511504d07af 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -235,11 +235,9 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
> blk_status_t rc;
>
> if (op_is_write(op))
> - rc = pmem_do_write(pmem, page, 0, sector,
> - hpage_nr_pages(page) * PAGE_SIZE);
> + rc = pmem_do_write(pmem, page, 0, sector, thp_size(page));
> else
> - rc = pmem_do_read(pmem, page, 0, sector,
> - hpage_nr_pages(page) * PAGE_SIZE);
> + rc = pmem_do_read(pmem, page, 0, sector, thp_size(page));
> /*
> * The ->rw_page interface is subtle and tricky. The core
> * retries on any error, so we can only invoke page_endio() in
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 6bec4b5b61e1..e944f9757349 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -271,6 +271,11 @@ static inline int hpage_nr_pages(struct page *page)
> return compound_nr(page);
> }
>
> +static inline unsigned long thp_size(struct page *page)
> +{
> + return page_size(page);
> +}
> +
> struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
> pmd_t *pmd, int flags, struct dev_pagemap **pgmap);
> struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
> @@ -329,6 +334,8 @@ static inline int hpage_nr_pages(struct page *page)
> return 1;
> }
>
> +#define thp_size(x) PAGE_SIZE
> +
> static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
> {
> return false;
> diff --git a/mm/internal.h b/mm/internal.h
> index f762a34b0c57..5efb13d5c226 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -386,7 +386,7 @@ vma_address(struct page *page, struct vm_area_struct *vma)
> unsigned long start, end;
>
> start = __vma_address(page, vma);
> - end = start + PAGE_SIZE * (hpage_nr_pages(page) - 1);
> + end = start + thp_size(page) - PAGE_SIZE;
>
> /* page should be within @vma mapping range */
> VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma);
> diff --git a/mm/page_io.c b/mm/page_io.c
> index 76965be1d40e..dd935129e3cb 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -41,7 +41,7 @@ static struct bio *get_swap_bio(gfp_t gfp_flags,
> bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9;
> bio->bi_end_io = end_io;
>
> - bio_add_page(bio, page, PAGE_SIZE * hpage_nr_pages(page), 0);
> + bio_add_page(bio, page, thp_size(page), 0);
> }
> return bio;
> }
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index 719c35246cfa..e65629c056e8 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -227,7 +227,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> if (pvmw->address >= pvmw->vma->vm_end ||
> pvmw->address >=
> __vma_address(pvmw->page, pvmw->vma) +
> - hpage_nr_pages(pvmw->page) * PAGE_SIZE)
> + thp_size(pvmw->page))
> return not_found(pvmw);
> /* Did we cross page table boundary? */
> if (pvmw->address % PMD_SIZE == 0) {
> @@ -268,7 +268,7 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
> unsigned long start, end;
>
> start = __vma_address(page, vma);
> - end = start + PAGE_SIZE * (hpage_nr_pages(page) - 1);
> + end = start + thp_size(page) - PAGE_SIZE;
>
> if (unlikely(end < vma->vm_start || start >= vma->vm_end))
> return 0;
>

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb