[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <6d19d790-92d2-40f9-9797-cc08bf3921fe@huawei.com>
Date: Thu, 15 Aug 2024 22:40:51 +0800
From: Kefeng Wang <wangkefeng.wang@...wei.com>
To: Yu Zhao <yuzhao@...gle.com>, Andrew Morton <akpm@...ux-foundation.org>,
Muchun Song <muchun.song@...ux.dev>
CC: "Matthew Wilcox (Oracle)" <willy@...radead.org>, Zi Yan <ziy@...dia.com>,
<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH mm-unstable v1 2/3] mm/cma: add cma_alloc_folio()
On 2024/8/12 5:21, Yu Zhao wrote:
> With alloc_contig_range() and free_contig_range() supporting large
> folios, CMA can allocate and free large folios too, by
> cma_alloc_folio() and cma_release().
>
> Signed-off-by: Yu Zhao <yuzhao@...gle.com>
> ---
> include/linux/cma.h | 1 +
> mm/cma.c | 47 ++++++++++++++++++++++++++++++---------------
> 2 files changed, 33 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9db877506ea8..086553fbda73 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -46,6 +46,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
> struct cma **res_cma);
> extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
> bool no_warn);
> +extern struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp);
> extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count);
> extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
>
> diff --git a/mm/cma.c b/mm/cma.c
> index 95d6950e177b..46feb06db8e7 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -403,18 +403,8 @@ static void cma_debug_show_areas(struct cma *cma)
> spin_unlock_irq(&cma->lock);
> }
>
> -/**
> - * cma_alloc() - allocate pages from contiguous area
> - * @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
> - *
> - * This function allocates part of contiguous memory on specific
> - * contiguous memory area.
> - */
> -struct page *cma_alloc(struct cma *cma, unsigned long count,
> - unsigned int align, bool no_warn)
> +static struct page *__cma_alloc(struct cma *cma, unsigned long count,
> + unsigned int align, gfp_t gfp)
> {
> unsigned long mask, offset;
> unsigned long pfn = -1;
> @@ -463,8 +453,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
>
> pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> mutex_lock(&cma_mutex);
> - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
> - GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
> + ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp);
> mutex_unlock(&cma_mutex);
> if (ret == 0) {
> page = pfn_to_page(pfn);
> @@ -494,7 +483,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
> page_kasan_tag_reset(nth_page(page, i));
> }
>
> - if (ret && !no_warn) {
> + if (ret && !(gfp & __GFP_NOWARN)) {
> pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
> __func__, cma->name, count, ret);
> cma_debug_show_areas(cma);
> @@ -513,6 +502,34 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
> return page;
> }
>
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @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
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, unsigned long count,
> + unsigned int align, bool no_warn)
> +{
> + return __cma_alloc(cma, count, align, GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
> +}
> +
> +struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp)
> +{
> + struct page *page;
> +
> + if (WARN_ON(order && !(gfp | __GFP_COMP)))
> + return NULL;
> +
> + page = __cma_alloc(cma, 1 << order, order, gfp);
> +
> + return page ? page_folio(page) : NULL;
We don't set large_rmappable for cma alloc folio, which is not consistent
with other folio allocation, eg folio_alloc/folio_alloc_mpol(),
there is no issue for HugeTLB folio, and for HugeTLB folio must without
large_rmappable, but once we use it for mTHP/THP, it need some extra
handle, maybe we set large_rmappable here, and clear it in
init_new_hugetlb_folio()?
> +}
> +
> bool cma_pages_valid(struct cma *cma, const struct page *pages,
> unsigned long count)
> {
Powered by blists - more mailing lists