Re: [PATCH] dcache: Translating dentry into pathname without takingrename_lock

From: Al Viro
Date: Thu Sep 05 2013 - 00:20:14 EST


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...
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