From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
mtk.manpages@gmail.com
Subject: Re: [PATCH 3/3] 64-bit futexes: x86 support
Date: Fri, 30 May 2008 19:25:06 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.1.10.0805301923020.3141@woody.linux-foundation.org> (raw)
In-Reply-To: <200805310127.m4V1RLdP013819@devserv.devel.redhat.com>
On Fri, 30 May 2008, Ulrich Drepper wrote:
>
> +#ifdef CONFIG_X86_32
> + /* Not all 32-bit machines support 8-byte cmpxchg. We just
> + unconditionally perform a runtime check for the feature. */
> + if ((op & FUTEX_FLAG_64) && !boot_cpu_has(X86_FEATURE_CX8))
> + return -ENOSYS;
> +#endif
Also, doesn't this mean that effectively you have given up on any CPU
before the Pentium entirely?
Not that I want to take the patches _anyway_, but it seems doubly stupid.
Those things are going to be UP machines, so you could have just emulated
it with no correctness issues by disabling preemption.
Linus
next prev parent reply other threads:[~2008-05-31 2:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-31 1:27 Ulrich Drepper
2008-05-31 2:25 ` Linus Torvalds [this message]
2008-05-31 3:18 ` Ulrich Drepper
2008-05-31 3:59 ` Linus Torvalds
2008-05-31 4:25 ` Ulrich Drepper
2008-05-31 4:34 ` Linus Torvalds
2008-05-31 4:45 ` Ulrich Drepper
2008-05-31 7:47 ` David Miller
2008-06-02 8:22 ` Ingo Molnar
2008-06-02 18:43 ` Ingo Molnar
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