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 <20220121075515.79311-3-songmuchun@bytedance.com> <Ye5XEeMYt8c7/iMV@infradead.org>
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From:   Muchun Song <songmuchun@bytedance.com>
Date:   Mon, 24 Jan 2022 17:01:03 +0800
Message-ID: <CAMZfGtWForYqmrZJFfOVw5pQPq8idQxwT9aFcUuCJMjdE6Tf3Q@mail.gmail.com>
Subject: Re: [PATCH 3/5] mm: page_vma_mapped: support checking if a pfn is
 mapped into a vma
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Dan Williams <dan.j.williams@intel.com>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>, apopple@nvidia.com,
        Yang Shi <shy828301@gmail.com>, rcampbell@nvidia.com,
        Hugh Dickins <hughd@google.com>,
        Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        zwisler@kernel.org, linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        nvdimm@lists.linux.dev, LKML <linux-kernel@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>
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On Mon, Jan 24, 2022 at 3:36 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Jan 21, 2022 at 03:55:13PM +0800, Muchun Song wrote:
> > +     if (pvmw->pte && ((pvmw->flags & PVMW_PFN_WALK) || !PageHuge(pvmw->page)))
>
> Please avoid the overly long line here and in a few other places.

OK.

>
> > +/*
> > + * Then at what user virtual address will none of the page be found in vma?
>
> Doesn't parse, what is this trying to say?

Well, I am also confused.

BTW, this is not introduced by me, it is introduced by:

  commit 37ffe9f4d7ff ("mm/thp: fix vma_address() if virtual address
below file offset")

If it is really confusing, I can replace this line with:

"Return the end user virtual address of a page within a vma"

Thanks.