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Date:   Mon, 12 Aug 2019 16:38:29 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Song Liu <songliubraving@fb.com>
Cc:     linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, matthew.wilcox@oracle.com,
        kirill.shutemov@linux.intel.com, kernel-team@fb.com,
        william.kucharski@oracle.com, akpm@linux-foundation.org,
        hdanton@sina.com
Subject: Re: [PATCH v10 7/7] mm,thp: avoid writes to file with THP in
 pagecache
Message-ID: <20190812203829.GC15498@cmpxchg.org>
References: <20190801184244.3169074-1-songliubraving@fb.com>
 <20190801184244.3169074-8-songliubraving@fb.com>
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On Thu, Aug 01, 2019 at 11:42:44AM -0700, Song Liu wrote:
> In previous patch, an application could put part of its text section in
> THP via madvise(). These THPs will be protected from writes when the
> application is still running (TXTBSY). However, after the application
> exits, the file is available for writes.
> 
> This patch avoids writes to file THP by dropping page cache for the file
> when the file is open for write. A new counter nr_thps is added to struct
> address_space. In do_dentry_open(), if the file is open for write and
> nr_thps is non-zero, we drop page cache for the whole file.
> 
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Reported-by: kbuild test robot <lkp@intel.com>
> Acked-by: Rik van Riel <riel@surriel.com>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Song Liu <songliubraving@fb.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>