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From:   Yang Shi <shy828301@gmail.com>
Date:   Wed, 23 Mar 2022 19:46:59 -0700
Message-ID: <CAHbLzkqTeD_VB0znsBNt8HjjPceqU-uKh6TF3jNVVjZn4dbBLw@mail.gmail.com>
Subject: Re: [v2 PATCH 0/8] Make khugepaged collapse readonly FS THP more consistent
To:     "Theodore Ts'o" <tytso@mit.edu>
Cc:     Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Song Liu <songliubraving@fb.com>,
        Rik van Riel <riel@surriel.com>,
        Matthew Wilcox <willy@infradead.org>, Zi Yan <ziy@nvidia.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        darrick.wong@oracle.com, Linux MM <linux-mm@kvack.org>,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Wed, Mar 23, 2022 at 6:48 PM Theodore Ts'o <tytso@mit.edu> wrote:
>
> On Thu, Mar 17, 2022 at 04:48:19PM -0700, Yang Shi wrote:
> >
> > The patch 1 ~ 7 are minor bug fixes, clean up and preparation patches.
> > The patch 8 converts ext4 and xfs.  We may need convert more filesystems,
> > but I'd like to hear some comments before doing that.
>
> Adding a hard-coded call to khugepage_enter_file() in ext4 and xfs,
> and potentially, each file system, seems kludgy as all heck.  Is there
> any reason not to simply call it in the mm code which calls f_op->mmap()?

Thanks, Ted. Very good point. I just didn't think of it. I think it is
doable. We may be able to clean up the code further.

>
>                                  - Ted