linux-kernel - Re: [patch] epoll use a single inode ...

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Message-ID: <20070307221401.GA16938@kryten>
Date:	Wed, 7 Mar 2007 16:14:02 -0600
From:	Anton Blanchard <anton@...ba.org>
To:	Eric Dumazet <dada1@...mosbay.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Davide Libenzi <davidel@...ilserver.org>,
	Avi Kivity <avi@...o.co.il>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@...iv.linux.org.uk>
Subject: Re: [patch] epoll use a single inode ...


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
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