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Date:   Sun, 23 Jan 2022 23:34:22 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     dan.j.williams@intel.com, willy@infradead.org, jack@suse.cz,
        viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
        apopple@nvidia.com, shy828301@gmail.com, rcampbell@nvidia.com,
        hughd@google.com, xiyuyang19@fudan.edu.cn,
        kirill.shutemov@linux.intel.com, zwisler@kernel.org,
        linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/5] mm: rmap: fix cache flush on THP pages
Message-ID: <Ye5WfvUdJBhZ3lME@infradead.org>
References: <20220121075515.79311-1-songmuchun@bytedance.com>
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On Fri, Jan 21, 2022 at 03:55:11PM +0800, Muchun Song wrote:
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index b0fd9dc19eba..65670cb805d6 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -974,7 +974,7 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
>  			if (!pmd_dirty(*pmd) && !pmd_write(*pmd))
>  				continue;
>  
> -			flush_cache_page(vma, address, page_to_pfn(page));
> +			flush_cache_range(vma, address, address + HPAGE_PMD_SIZE);

Do we need a flush_cache_folio here given that we must be dealing with
what effectively is a folio here?

Also please avoid the overly long line.