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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Adam Litke <agl@us.ibm.com>,
	Kumar Gala <galak@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH v3] powerpc: properly reserve in bootmem the lmb reserved regions that cross NUMA nodes
Date: Fri, 10 Oct 2008 15:55:16 +1100	[thread overview]
Message-ID: <1223614516.8157.154.camel@pasglop> (raw)
In-Reply-To: <48EE6720.6010601@linux.vnet.ibm.com>

On Thu, 2008-10-09 at 15:18 -0500, Jon Tollefson wrote:
> If there are multiple reserved memory blocks via lmb_reserve() that are
> contiguous addresses and on different NUMA nodes we are losing track of which 
> address ranges to reserve in bootmem on which node.  I discovered this 
> when I recently got to try 16GB huge pages on a system with more then 2 nodes.

I'm going to apply it, however, could you double check something for
me ? A cursory glance of the new version makes me wonder, what if the
first call to get_node_active_region() ends up with the work_fn never
hitting the if () case ? I think in that case, node_ar->end_pfn never
gets initialized right ? Can that happen in practice ? I suspect that
isn't the case but better safe than sorry...

If there's indeed a potential problem, please send a fixup patch.

Cheers,
Ben.



WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Adam Litke <agl@us.ibm.com>,
	Kumar Gala <galak@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH v3] powerpc: properly reserve in bootmem the lmb reserved regions that cross NUMA nodes
Date: Fri, 10 Oct 2008 15:55:16 +1100	[thread overview]
Message-ID: <1223614516.8157.154.camel@pasglop> (raw)
In-Reply-To: <48EE6720.6010601@linux.vnet.ibm.com>

On Thu, 2008-10-09 at 15:18 -0500, Jon Tollefson wrote:
> If there are multiple reserved memory blocks via lmb_reserve() that are
> contiguous addresses and on different NUMA nodes we are losing track of which 
> address ranges to reserve in bootmem on which node.  I discovered this 
> when I recently got to try 16GB huge pages on a system with more then 2 nodes.

I'm going to apply it, however, could you double check something for
me ? A cursory glance of the new version makes me wonder, what if the
first call to get_node_active_region() ends up with the work_fn never
hitting the if () case ? I think in that case, node_ar->end_pfn never
gets initialized right ? Can that happen in practice ? I suspect that
isn't the case but better safe than sorry...

If there's indeed a potential problem, please send a fixup patch.

Cheers,
Ben.


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WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH v3] powerpc: properly reserve in bootmem the lmb reserved regions that cross NUMA nodes
Date: Fri, 10 Oct 2008 15:55:16 +1100	[thread overview]
Message-ID: <1223614516.8157.154.camel@pasglop> (raw)
In-Reply-To: <48EE6720.6010601@linux.vnet.ibm.com>

On Thu, 2008-10-09 at 15:18 -0500, Jon Tollefson wrote:
> If there are multiple reserved memory blocks via lmb_reserve() that are
> contiguous addresses and on different NUMA nodes we are losing track of which 
> address ranges to reserve in bootmem on which node.  I discovered this 
> when I recently got to try 16GB huge pages on a system with more then 2 nodes.

I'm going to apply it, however, could you double check something for
me ? A cursory glance of the new version makes me wonder, what if the
first call to get_node_active_region() ends up with the work_fn never
hitting the if () case ? I think in that case, node_ar->end_pfn never
gets initialized right ? Can that happen in practice ? I suspect that
isn't the case but better safe than sorry...

If there's indeed a potential problem, please send a fixup patch.

Cheers,
Ben.

  reply	other threads:[~2008-10-10  5:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-09 20:18 [PATCH v3] powerpc: properly reserve in bootmem the lmb reserved regions that cross NUMA nodes Jon Tollefson
2008-10-09 20:18 ` Jon Tollefson
2008-10-10  4:55 ` Benjamin Herrenschmidt [this message]
2008-10-10  4:55   ` Benjamin Herrenschmidt
2008-10-10  4:55   ` Benjamin Herrenschmidt
2008-10-17  4:59   ` Jon Tollefson
2008-10-17  4:59     ` Jon Tollefson
2008-10-17  4:59     ` Jon Tollefson
2009-02-11  3:17 ` problem with numa reserve bootmem Geoff Levand
2009-02-11  3:55   ` Michael Ellerman
2009-02-12 22:36   ` [patch] powerpc: fix numa reserve bootmem page selection Geoff Levand

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