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Date:   Wed, 20 Jul 2022 04:02:40 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     cgel.zte@gmail.com
Cc:     viro@zeniv.linux.org.uk, hughd@google.com,
        akpm@linux-foundation.org, hch@infradead.org,
        hsiangkao@linux.alibaba.com, yang.yang29@zte.com.cn,
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        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Ran Xiaokai <ran.xiaokai@zte.com.cn>
Subject: Re: [PATCH] fs: drop_caches: skip dropping pagecache which is always
 dirty
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References: <20220720022118.1495752-1-yang.yang29@zte.com.cn>
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On Wed, Jul 20, 2022 at 02:21:19AM +0000, cgel.zte@gmail.com wrote:
> From: Yang Yang <yang.yang29@zte.com.cn>
> 
> Pagecache of some kind of fs has PG_dirty bit set once it was
> allocated, so it can't be dropped. These fs include ramfs and
> tmpfs. This can make drop_pagecache_sb() more efficient.

Why do we want to make drop_pagecache_sb() more efficient?