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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Waiman Long <waiman.long@hp.com>,
	Scott J Norton <scott.norton@hp.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	"Chandramouleeswaran, Aswin" <aswin@hp.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] dcache: Translating dentry into pathname without taking rename_lock
Date: Thu, 5 Sep 2013 05:20:00 +0100	[thread overview]
Message-ID: <20130905041959.GN13318@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFyURmAMo1Hso1_2zzcNEfcqOLUyhLGrBhvtMXWMJHVMfg@mail.gmail.com>

On Wed, Sep 04, 2013 at 07:48:14PM -0700, Linus Torvalds wrote:
>  - use the name length as a maximum
> 
>  - do a byte-at-a-time copy, stopping at a zero (it's going to be
> faster than memchr anyway)
> 
> Then, later on, we can do one that does a word-at-a-time using the
> CONFIG_DCACHE_WORD_ACCESS magic: we know dentry names are always
> word-aligned, and we have an efficient "has_zero()" function for
> finding zero bytes in a word.

Umm...  Dentry names are word-aligned, but the place where we copy them
doesn't have to be.  OTOH, DCACHE_WORD_ACCESS is for architectures where
unaligned stores are fine, so...

  reply	other threads:[~2013-09-05  4:20 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-04 19:05 [PATCH] dcache: Translating dentry into pathname without taking rename_lock Waiman Long
2013-09-04 19:11 ` Al Viro
2013-09-04 19:33   ` Waiman Long
2013-09-04 19:43     ` Al Viro
2013-09-05  1:55       ` Waiman Long
2013-09-05  2:42         ` Al Viro
     [not found]   ` <CA+55aFwW+hWwQd8+NgukSidHbf2bnd6QO0yKK9NAgX+9rt0cOQ@mail.gmail.com>
     [not found]     ` <5227E321.4090008@hp.com>
2013-09-05  2:48       ` Linus Torvalds
2013-09-05  4:20         ` Al Viro [this message]
2013-09-04 19:26 ` Waiman Long
2013-09-04 20:40   ` John Stoffel
2013-09-05  2:04     ` Waiman Long
2013-09-05 13:29       ` John Stoffel
2013-09-05 17:28         ` Waiman Long
2013-09-04 21:31 ` Linus Torvalds
2013-09-05  2:17   ` Waiman Long
  -- strict thread matches above, loose matches on Subject: below --
2013-09-05  4:30 George Spelvin
2013-09-05 17:06 ` Waiman Long

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