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Date: Wed, 27 Dec 2006 19:49:59 -0800
From: Andrew Morton <akpm@osdl.org>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drop page cache of a single file
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On Thu, 28 Dec 2006 11:17:25 +0800
"Zhang, Yanmin" <yanmin_zhang@linux.intel.com> wrote:

> Currently, by /proc/sys/vm/drop_caches, applications could drop pagecache,
> slab(dentries and inodes), or both, but applications couldn't choose to
> just drop the page cache of one file. An user of VOD (Video-On-Demand)
> needs this capability to have more detailed control on page cache release.

The posix_fadvise() system call should be used for this.  Probably in
combination with sys_sync_file_range().