From: David Rientjes <rientjes@google.com>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: "Américo Wang" <xiyou.wangcong@gmail.com>,
linux-kernel@vger.kernel.org, linux-numa@vger.kernel.org,
"Alan Piszcz" <ap@solarrain.com>
Subject: Re: 3.1-rc2: CONFIG_NUMA Question
Date: Fri, 19 Aug 2011 12:25:03 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1108191223230.20477@chino.kir.corp.google.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1108180758290.7903@p34.internal.lan>
On Thu, 18 Aug 2011, Justin Piszcz wrote:
> > The max of NUMA nodes is specified by CONFIG_NODES_SHIFT,
> > in your case, it is 6, which means it supports up to 2^6 nodes.
> Ok, is there any overhead having more than is needed?
>
Yeah, try to avoid going above 8 because that causes nodemasks that are
typically allocated on the stack of kernel text to be dynamically
allocated through the slab allocator to avoid the possibility of overflow.
I doubt you have the need for more than 64 nodes, so I'd highly recommend
leaving it at the default unless you want to debug or test some large
numa=fake settings.
prev parent reply other threads:[~2011-08-19 19:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-18 10:51 3.1-rc2: CONFIG_NUMA Question Justin Piszcz
2011-08-18 11:51 ` Américo Wang
2011-08-18 11:59 ` Justin Piszcz
2011-08-19 19:25 ` David Rientjes [this message]
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