Re: [PATCH v3 1/4] mm: cma: introduce gfp flag in cma_alloc instead of no_warn

[Suren Baghdasaryan <surenb@google.com>]

On Tue, Jan 12, 2021 at 5:21 PM Minchan Kim <minchan@kernel.org> wrote:
>
> The upcoming patch will introduce __GFP_NORETRY semantic
> in alloc_contig_range which is a failfast mode of the API.
> Instead of adding a additional parameter for gfp, replace
> no_warn with gfp flag.
>
> To keep old behaviors, it follows the rule below.
>
>   no_warn                       gfp_flags
>
>   false                         GFP_KERNEL
>   true                          GFP_KERNEL|__GFP_NOWARN
>   gfp & __GFP_NOWARN            GFP_KERNEL | (gfp & __GFP_NOWARN)
>
> Signed-off-by: Minchan Kim <minchan@kernel.org>

Reviewed-by: Suren Baghdasaryan <surenb@google.com>

> ---
>  drivers/dma-buf/heaps/cma_heap.c |  2 +-
>  drivers/s390/char/vmcp.c         |  2 +-
>  include/linux/cma.h              |  2 +-
>  kernel/dma/contiguous.c          |  3 ++-
>  mm/cma.c                         | 12 ++++++------
>  mm/cma_debug.c                   |  2 +-
>  mm/hugetlb.c                     |  6 ++++--
>  mm/secretmem.c                   |  3 ++-
>  8 files changed, 18 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
> index 364fc2f3e499..0afc1907887a 100644
> --- a/drivers/dma-buf/heaps/cma_heap.c
> +++ b/drivers/dma-buf/heaps/cma_heap.c
> @@ -298,7 +298,7 @@ static int cma_heap_allocate(struct dma_heap *heap,
>         if (align > CONFIG_CMA_ALIGNMENT)
>                 align = CONFIG_CMA_ALIGNMENT;
>
> -       cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
> +       cma_pages = cma_alloc(cma_heap->cma, pagecount, align, GFP_KERNEL);
>         if (!cma_pages)
>                 goto free_buffer;
>
> diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
> index 9e066281e2d0..78f9adf56456 100644
> --- a/drivers/s390/char/vmcp.c
> +++ b/drivers/s390/char/vmcp.c
> @@ -70,7 +70,7 @@ static void vmcp_response_alloc(struct vmcp_session *session)
>          * anymore the system won't work anyway.
>          */
>         if (order > 2)
> -               page = cma_alloc(vmcp_cma, nr_pages, 0, false);
> +               page = cma_alloc(vmcp_cma, nr_pages, 0, GFP_KERNEL);
>         if (page) {
>                 session->response = (char *)page_to_phys(page);
>                 session->cma_alloc = 1;
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 217999c8a762..d6c02d08ddbc 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -45,7 +45,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
>                                         const char *name,
>                                         struct cma **res_cma);
>  extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
> -                             bool no_warn);
> +                             gfp_t gfp_mask);
>  extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count);
>
>  extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data);
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index 3d63d91cba5c..552ed531c018 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -260,7 +260,8 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
>         if (align > CONFIG_CMA_ALIGNMENT)
>                 align = CONFIG_CMA_ALIGNMENT;
>
> -       return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
> +       return cma_alloc(dev_get_cma_area(dev), count, align, GFP_KERNEL |
> +                       (no_warn ? __GFP_NOWARN : 0));
>  }
>
>  /**
> diff --git a/mm/cma.c b/mm/cma.c
> index 0ba69cd16aeb..35053b82aedc 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -419,13 +419,13 @@ static inline void cma_debug_show_areas(struct cma *cma) { }
>   * @cma:   Contiguous memory region for which the allocation is performed.
>   * @count: Requested number of pages.
>   * @align: Requested alignment of pages (in PAGE_SIZE order).
> - * @no_warn: Avoid printing message about failed allocation
> + * @gfp_mask: GFP mask to use during during the cma allocation.
>   *
>   * This function allocates part of contiguous memory on specific
>   * contiguous memory area.
>   */
>  struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
> -                      bool no_warn)
> +                      gfp_t gfp_mask)
>  {
>         unsigned long mask, offset;
>         unsigned long pfn = -1;
> @@ -438,8 +438,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
>         if (!cma || !cma->count || !cma->bitmap)
>                 return NULL;
>
> -       pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
> -                count, align);
> +       pr_debug("%s(cma %p, count %zu, align %d gfp_mask 0x%x)\n", __func__,
> +                       (void *)cma, count, align, gfp_mask);
>
>         if (!count)
>                 return NULL;
> @@ -471,7 +471,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
>
>                 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
>                 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
> -                                    GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
> +                                               gfp_mask);
>
>                 if (ret == 0) {
>                         page = pfn_to_page(pfn);
> @@ -500,7 +500,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
>                         page_kasan_tag_reset(page + i);
>         }
>
> -       if (ret && !no_warn) {
> +       if (ret && !(gfp_mask & __GFP_NOWARN)) {
>                 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n",
>                         __func__, count, ret);
>                 cma_debug_show_areas(cma);
> diff --git a/mm/cma_debug.c b/mm/cma_debug.c
> index d5bf8aa34fdc..00170c41cf81 100644
> --- a/mm/cma_debug.c
> +++ b/mm/cma_debug.c
> @@ -137,7 +137,7 @@ static int cma_alloc_mem(struct cma *cma, int count)
>         if (!mem)
>                 return -ENOMEM;
>
> -       p = cma_alloc(cma, count, 0, false);
> +       p = cma_alloc(cma, count, 0, GFP_KERNEL);
>         if (!p) {
>                 kfree(mem);
>                 return -ENOMEM;
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 737b2dce19e6..695af33aa66c 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1266,7 +1266,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
>
>                 if (hugetlb_cma[nid]) {
>                         page = cma_alloc(hugetlb_cma[nid], nr_pages,
> -                                       huge_page_order(h), true);
> +                                       huge_page_order(h),
> +                                       GFP_KERNEL | __GFP_NOWARN);
>                         if (page)
>                                 return page;
>                 }
> @@ -1277,7 +1278,8 @@ static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
>                                         continue;
>
>                                 page = cma_alloc(hugetlb_cma[node], nr_pages,
> -                                               huge_page_order(h), true);
> +                                               huge_page_order(h),
> +                                               GFP_KERNEL | __GFP_NOWARN);
>                                 if (page)
>                                         return page;
>                         }
> diff --git a/mm/secretmem.c b/mm/secretmem.c
> index b8a32954ac68..585d55b9f9d8 100644
> --- a/mm/secretmem.c
> +++ b/mm/secretmem.c
> @@ -86,7 +86,8 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
>         struct page *page;
>         int err;
>
> -       page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE, gfp & __GFP_NOWARN);
> +       page = cma_alloc(secretmem_cma, nr_pages, PMD_SIZE,
> +                               GFP_KERNEL | (gfp & __GFP_NOWARN));
>         if (!page)
>                 return -ENOMEM;
>
> --
> 2.30.0.284.gd98b1dd5eaa7-goog
>