From: Andrew Morton <akpm@linux-foundation.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [patch] mm: fix PageUptodate memory ordering bug
Date: Sat, 22 Dec 2007 23:29:32 -0800 [thread overview]
Message-ID: <20071222232932.590e2b6c.akpm@linux-foundation.org> (raw)
In-Reply-To: <20071223071529.GC29288@wotan.suse.de>
On Sun, 23 Dec 2007 08:15:29 +0100 Nick Piggin <npiggin@suse.de> wrote:
> > That's just speculation. Please find out why such a small patch caused
> > such a large code size increase and see if it can be fixed.
>
> It's not actually increasing size by that much here... hmm, do you have
> CONFIG_X86_PPRO_FENCE defined, by any chance?
I expect it was just allmodconfig, so: yes
It's a quite repeatable experiment though.
> It looks like this gets defined by default for i386, and also probably for
> distro configs. Linus? This is a fairly heavy hammer for such an unlikely bug on
> such a small number of systems (that admittedly doesn't even fix the bug in all
> cases anyway). It's not only heavy for my proposed patch, but it also halves the
> speed of spinlocks. Can we have some special config option for this instead?
Sounds worthwhile, if we can't do it via altinstructions.
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next prev parent reply other threads:[~2007-12-23 7:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-18 1:26 Nick Piggin
2007-12-22 8:57 ` Andrew Morton
2007-12-22 12:14 ` Hugh Dickins
2007-12-23 6:54 ` Nick Piggin
2007-12-23 5:57 ` Nick Piggin
2007-12-23 6:32 ` Andrew Morton
2007-12-23 7:15 ` Nick Piggin
2007-12-23 7:29 ` Andrew Morton [this message]
2007-12-23 9:14 ` Nick Piggin
2007-12-23 9:28 ` Andrew Morton
2007-12-23 16:02 ` Andi Kleen
2007-12-30 16:33 ` Ingo Molnar
2008-01-01 23:26 ` Nick Piggin
2008-01-02 21:01 ` Andi Kleen
2008-01-03 3:32 ` Nick Piggin
2008-01-03 13:08 ` Andi Kleen
2007-12-23 17:22 ` Linus Torvalds
2007-12-23 21:35 ` Nick Piggin
2007-12-23 22:41 ` Nick Piggin
2008-01-01 23:41 ` Alan Cox
2008-01-02 11:02 ` [patch] i386: avoid expensive ppro ordering workaround for default 686 kernels Nick Piggin
2008-01-02 13:44 ` Alan Cox
2008-01-03 4:17 ` Nick Piggin
2008-01-03 14:23 ` Alan Cox
2008-01-03 20:20 ` Benjamin Herrenschmidt
2008-01-03 22:23 ` Alan Cox
2008-01-03 23:10 ` Nick Piggin
2008-01-04 16:27 ` Alan Cox
2008-01-07 0:12 ` Nick Piggin
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