From: Matthew Wilcox <matthew@wil.cx>
To: Li Wang <liwang@ubuntukylin.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Sage Weil <sage@inktank.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
LKML <linux-kernel@vger.kernel.org>,
Yunchuan Wen <yunchuanwen@ubuntukylin.com>
Subject: Re: [PATCH 0/5] VFS: Directory level cache cleaning
Date: Mon, 16 Dec 2013 20:58:48 -0700 [thread overview]
Message-ID: <20131217035847.GA10392@parisc-linux.org> (raw)
In-Reply-To: <52AFC020.10403@ubuntukylin.com>
On Tue, Dec 17, 2013 at 11:08:16AM +0800, Li Wang wrote:
> As far as we know, fadvise(DONTNEED) does not support metadata
> cache cleaning. We think that is desirable under massive small files
> situations. Another thing is that do people accept the behavior
> of feeding a directory fd to fadvise will recusively clean all
> page caches of files inside that directory?
I think there's a really good permissions-related question here.
If that's an acceptable interface, should one have to be CAP_SYS_ADMIN
to issue the request? What if some of the files below this directory
are not owned by the user issuing the request?
> On 2013/12/17 1:45, Cong Wang wrote:
>> On Mon, Dec 16, 2013 at 7:00 AM, Li Wang <liwang@ubuntukylin.com> wrote:
>>> This patch extend the 'drop_caches' interface to
>>> support directory level cache cleaning and has a complete
>>> backward compatibility. '{1,2,3}' keeps the same semantics
>>> as before. Besides, "{1,2,3}:DIRECTORY_PATH_NAME" is allowed
>>> to recursively clean the caches under DIRECTORY_PATH_NAME.
>>> For example, 'echo 1:/home/foo/jpg > /proc/sys/vm/drop_caches'
>>> will clean the page caches of the files inside 'home/foo/jpg'.
>>>
>>
>> This interface is ugly...
>>
>> And we already have a file-level drop cache, that is,
>> fadvise(DONTNEED). Can you extend it if it can't
>> handle a directory fd?
>>
> --
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--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2013-12-17 3:58 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 15:00 [PATCH 0/5] VFS: Directory level cache cleaning Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` [PATCH 1/5] VFS: Convert drop_caches to accept string Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` [PATCH 2/5] VFS: Convert sysctl_drop_caches to string Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` [PATCH 3/5] VFS: Add the declaration of shrink_pagecache_parent Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` [PATCH 4/5] VFS: Add shrink_pagecache_parent Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 15:00 ` [PATCH 5/5] VFS: Extend drop_caches sysctl handler to allow directory level cache cleaning Li Wang
2013-12-16 15:00 ` Li Wang
2013-12-16 17:45 ` [PATCH 0/5] VFS: Directory " Cong Wang
2013-12-16 17:45 ` Cong Wang
2013-12-17 3:08 ` Li Wang
2013-12-17 3:08 ` Li Wang
2013-12-17 3:58 ` Matthew Wilcox [this message]
2013-12-17 7:23 ` Li Wang
2013-12-17 7:23 ` Li Wang
2013-12-17 9:12 ` Li Zefan
2013-12-17 9:12 ` Li Zefan
2013-12-17 9:12 ` Li Zefan
2013-12-17 9:31 ` Li Wang
2013-12-17 9:31 ` Li Wang
2013-12-18 1:26 ` Li Zefan
2013-12-18 1:26 ` Li Zefan
2013-12-18 1:26 ` Li Zefan
2013-12-17 13:55 ` Michal Hocko
2013-12-17 13:55 ` Michal Hocko
2013-12-17 22:05 ` Dave Chinner
2013-12-17 22:05 ` Dave Chinner
2013-12-17 22:05 ` Dave Chinner
2013-12-18 1:36 ` Li Wang
2013-12-18 1:36 ` Li Wang
2013-12-18 1:36 ` Li Wang
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