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From: Andi Kleen <ak@muc.de>
To: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>,
	zwane@arm.linux.org.uk, discuss@x86-64.org, shaohua.li@intel.com,
	linux-kernel@vger.kernel.org, rusty@rustycorp.com.au
Subject: Re: [discuss] Re: [patch 0/4] CPU hot-plug support for x86_64
Date: 24 May 2005 20:17:43 +0200
Date: Tue, 24 May 2005 20:17:43 +0200	[thread overview]
Message-ID: <20050524181743.GG86233@muc.de> (raw)
In-Reply-To: <20050524085330.GB8279@in.ibm.com>

On Tue, May 24, 2005 at 02:23:30PM +0530, Srivatsa Vaddagiri wrote:
> On Mon, May 23, 2005 at 11:01:06PM -0700, Ashok Raj wrote:
> > We do this today in x86_64 case when we setup this upcomming cpu in 
> > cpu_online_map. But the issue is when we use ipi broadcast, its an ugly
> 
> I don't know of x86-64, but atleast on x86 ipi broadcast will send 
> to _all_ CPUs present, right? I mean the h/w does not know of the offline
> CPUs and will send to them also. This could lead to a problem for the offline 
> CPUs when they come online and can take a spurious IPI (unless
> there is support in h/w to clear pending IPI before doing STI).

x86-64 works the same here. 

The hardware does not clear pending IPIs AFAIK, but software could
do that manually during cpu bootup. Races can be avoided by taking
call_lock and the tlb flush lock while doing that.

-Andi

  reply	other threads:[~2005-05-24 18:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-20 22:16 [patch 0/4] CPU hot-plug support for x86_64 Ashok Raj
2005-05-20 22:16 ` [patch 1/4] " Ashok Raj
2005-05-20 22:16 ` [patch 2/4] " Ashok Raj
2005-05-23 16:38   ` Andi Kleen
2005-05-23 16:58     ` Ashok Raj
2005-05-23 17:24       ` Andi Kleen
2005-05-23 17:32         ` Ashok Raj
2005-05-23 19:37     ` Rafael J. Wysocki
2005-05-24 11:49       ` Andi Kleen
2005-05-20 22:16 ` [patch 3/4] " Ashok Raj
2005-05-20 22:16 ` [patch 4/4] " Ashok Raj
2005-05-23 16:40 ` [patch 0/4] " Andi Kleen
2005-05-23 16:54   ` Ashok Raj
2005-05-23 17:12     ` Andi Kleen
2005-05-23 17:40       ` [discuss] " Ashok Raj
2005-05-24  5:46         ` Srivatsa Vaddagiri
2005-05-24  6:01           ` Ashok Raj
2005-05-24  8:53             ` Srivatsa Vaddagiri
2005-05-24 18:17               ` Andi Kleen [this message]
2005-05-24 11:50           ` Andi Kleen
2005-05-24 11:48         ` Andi Kleen
2005-05-24 17:01           ` Srivatsa Vaddagiri

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