From: Andi Kleen <andi@firstfloor.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: torvalds@linux-foundation.org, andi@firstfloor.org,
hpa@zytor.com, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Re: Word-at-a-time dcache name accesses (was Re: .. anybody know ofany filesystems that depend on the exact VFS 'namehash' implementation?)
Date: Sun, 4 Mar 2012 05:31:07 +0100 [thread overview]
Message-ID: <20120304043107.GC22197@one.firstfloor.org> (raw)
In-Reply-To: <201203041127.IDI56216.FHOQMOVLtOFSJF@I-love.SAKURA.ne.jp>
On Sun, Mar 04, 2012 at 11:27:01AM +0900, Tetsuo Handa wrote:
> A passer-by's mumble.
>
> We are discussing about systems with huge "struct dentry" instances where
> selecting a hash list based on "struct qstr"->hash cannot effectively narrow
> down candidates to compare, aren't we?
This is effectively a simple bloom filter.
Would be only worth it if longer hash chains are common. And if that's the case
we should probably have either a larger table or a better hash (or both)
-Andi
next prev parent reply other threads:[~2012-03-04 4:31 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-02 23:46 Word-at-a-time dcache name accesses (was Re: .. anybody know of any filesystems that depend on the exact VFS 'namehash' implementation?) Linus Torvalds
2012-03-03 0:02 ` Ted Ts'o
2012-03-03 0:17 ` david
2012-03-03 0:24 ` Linus Torvalds
2012-03-04 22:19 ` Matthew Wilcox
2012-03-04 23:27 ` Linus Torvalds
2012-03-03 0:17 ` Linus Torvalds
2012-03-03 0:38 ` H. Peter Anvin
2012-03-03 0:57 ` Linus Torvalds
2012-03-03 1:02 ` H. Peter Anvin
2012-03-03 1:11 ` Linus Torvalds
2012-03-03 1:17 ` H. Peter Anvin
2012-03-03 16:12 ` Word-at-a-time dcache name accesses Andi Kleen
2012-03-03 18:47 ` H. Peter Anvin
2012-03-03 20:10 ` Word-at-a-time dcache name accesses (was Re: .. anybody know of any filesystems that depend on the exact VFS 'namehash' implementation?) Linus Torvalds
2012-03-04 2:27 ` Word-at-a-time dcache name accesses (was Re: .. anybody know ofany " Tetsuo Handa
2012-03-04 4:31 ` Andi Kleen [this message]
2012-03-05 3:58 ` Word-at-a-time dcache name accesses (was Re: .. anybody know of any " Jason Garrett-Glaser
2012-03-05 5:38 ` Linus Torvalds
2012-03-27 4:42 ` Brian Gerst
2012-03-27 5:02 ` Dave Jones
2012-03-27 5:31 ` Brian Gerst
2012-03-28 0:39 ` Linus Torvalds
2012-03-28 0:50 ` Linus Torvalds
2012-03-28 0:56 ` Brian Gerst
[not found] ` <CACvQF53YasSCUit2KoWDimgObknCz++aU90MesSfvAZTeUFQHw@mail.gmail.com>
2013-04-04 16:50 ` Lai Jiangshan
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