Re: [PATCH 1/3] fs: aio: use a folio in aio_setup_ring()

From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
	Benjamin LaHaise <bcrl@kvack.org>,
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	<linux-kernel@vger.kernel.org>,
	Matthew Wilcox <willy@infradead.org>
Cc: <linux-aio@kvack.org>, <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 1/3] fs: aio: use a folio in aio_setup_ring()
Date: Thu, 21 Mar 2024 17:07:58 +0800	[thread overview]
Message-ID: <45a2ab40-bc03-417e-9b9a-bb140e5f3444@huawei.com> (raw)
In-Reply-To: <20240321082733.614329-2-wangkefeng.wang@huawei.com>


On 2024/3/21 16:27, Kefeng Wang wrote:
> Use a folio throughout aio_setup_ring() to remove calls to compound_head().
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   fs/aio.c | 21 ++++++++++++---------
>   1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/aio.c b/fs/aio.c
> index 9cdaa2faa536..d7f6c8705016 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -527,17 +527,20 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
>   	}
>   
>   	for (i = 0; i < nr_pages; i++) {
> -		struct page *page;
> -		page = find_or_create_page(file->f_mapping,
> -					   i, GFP_USER | __GFP_ZERO);
> -		if (!page)
> +		struct folio *folio;
> +
> +		folio = __filemap_get_folio(file->f_mapping, i,
> +					    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
> +					    GFP_USER | __GFP_ZERO);
> +		if (!folio)
Oh, this should be  if (IS_ERR(folio)), will update.

>   			break;
> -		pr_debug("pid(%d) page[%d]->count=%d\n",
> -			 current->pid, i, page_count(page));
> -		SetPageUptodate(page);
> -		unlock_page(page);
>   
> -		ctx->ring_pages[i] = page;
> +		pr_debug("pid(%d) [%d] folio->count=%d\n", current->pid, i,
> +			 folio_ref_count(folio));
> +		folio_mark_uptodate(folio);
> +		folio_unlock(folio);
> +
> +		ctx->ring_pages[i] = &folio->page;
>   	}
>   	ctx->nr_pages = i;
>