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From: Prarit Bhargava <prarit@redhat.com>
To: ykzhao <yakui.zhao@intel.com>
Cc: Matthew Garrett <mjg@redhat.com>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>
Subject: Re: [RFC PATCH]: ACPI: Automatically online hot-added memory
Date: Wed, 10 Mar 2010 08:28:03 -0500	[thread overview]
Message-ID: <4B979E63.1070806@redhat.com> (raw)
In-Reply-To: <1268186225.3606.25.camel@localhost.localdomain>


>
> Why do we need to see whether the memory is onlined before bringing cpu
> to online state? It seems that there is no dependency between cpu online
> and memory online.
>
>   

Yakui,

Here's a deeper look into the issue.  New Intel processors have an 
on-die memory controller and this means that as the socket comes and 
goes, so does the memory "behind" the socket.

ie) with new processors it is possible that an entire node which 
consists of memory and cpus comes and goes with the socket enable and 
disable.

The cpu bringup code does local node allocations for the cpu.  If the 
memory connected to the node (which is "behind" the socket) isn't 
online, then these allocations fail, and then the cpu bringup fails.

P.


  reply	other threads:[~2010-03-10 13:28 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-09 14:12 [RFC PATCH]: ACPI: Automatically online hot-added memory Prarit Bhargava
2010-03-09 15:42 ` Matthew Garrett
2010-03-09 18:27   ` Prarit Bhargava
2010-03-10  1:57     ` ykzhao
2010-03-10 13:28       ` Prarit Bhargava [this message]
2010-03-11  0:55         ` ykzhao
2010-03-11  2:18           ` Prarit Bhargava
2010-03-11  8:07             ` ykzhao
2010-03-11  8:32               ` chen gong
2010-03-11 11:25                 ` Prarit Bhargava
2010-03-12 13:18                 ` Thomas Renninger
2010-03-17 18:47                   ` Prarit Bhargava
2010-03-19 16:55                     ` Thomas Renninger
2010-03-19 17:23                       ` Prarit Bhargava
2010-03-20 20:51                         ` Thomas Renninger
2010-03-24 14:40                     ` Thomas Renninger
2010-03-24 15:16                       ` Prarit Bhargava
2010-03-11 11:18               ` Prarit Bhargava
2010-03-12  1:31                 ` ykzhao
2010-03-12 13:01           ` Thomas Renninger
2010-03-17 15:24             ` Prarit Bhargava
2010-03-09 19:10 ` Alex Chiang
2010-03-09 19:10   ` Alex Chiang
2010-03-09 19:15   ` Prarit Bhargava
2010-03-09 19:15     ` Prarit Bhargava

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