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Date: Wed, 7 Mar 2007 16:14:02 -0600
From: Anton Blanchard <anton@samba.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Davide Libenzi <davidel@xmailserver.org>, Avi Kivity <avi@argo.co.il>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [patch] epoll use a single inode ...
Message-ID: <20070307221401.GA16938@kryten>
References: <45ED1A3C.6030707@argo.co.il> <200703071906.58405.dada1@cosmosbay.com> <Pine.LNX.4.64.0703071022390.5963@woody.linux-foundation.org> <200703071952.13219.dada1@cosmosbay.com>
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Hi,

> Well, I hope a prefetch(NULL) is OK because we are doing millions of
> them (see include/linux/list.h :) )

Funny you mention this. We found some noticeable ppc64 regressions when
moving the dcache to standard list macros and had to do this to fix it
up:

static inline void prefetch(const void *x)
{
        if (unlikely(!x))
                return;

        __asm__ __volatile__ ("dcbt 0,%0" : : "r" (x));
}

Urgh :)

Anton