linux-kernel - Re: [PATCH] drivers/base/node.c: export physical address range of given node (Re: NUMA node information for pages)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <53481724.8020304@intel.com>
Date:	Fri, 11 Apr 2014 09:24:04 -0700
From:	Dave Hansen <dave.hansen@...el.com>
To:	David Rientjes <rientjes@...gle.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
CC:	drepper@...il.com, anatol.pomozov@...il.com, jkosina@...e.cz,
	akpm@...ux-foundation.org, xemul@...allels.com,
	paul.gortmaker@...driver.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: Re: [PATCH] drivers/base/node.c: export physical address range of
 given node (Re: NUMA node information for pages)

On 04/11/2014 04:00 AM, David Rientjes wrote:
> On Thu, 10 Apr 2014, Naoya Horiguchi wrote:
>> > Yes, that's right, but it seems to me that just node_start_pfn and node_end_pfn
>> > is not enough because there can be holes (without any page struct backed) inside
>> > [node_start_pfn, node_end_pfn), and it's not aware of memory hotplug.
>> > 
> So?  Who cares if there are non-addressable holes in part of the span?  
> Ulrich, correct me if I'm wrong, but it seems you're looking for just a 
> address-to-nodeid mapping (or pfn-to-nodeid mapping) and aren't actually 
> expecting that there are no holes in a node for things like acpi or I/O or 
> reserved memory.
...
> I think trying to represent holes and handling different memory models and 
> hotplug in special ways is complete overkill.

This isn't just about memory hotplug or different memory models.  There
are systems out there today, in production, that have layouts like this:

|------Node0-----|
     |------Node1-----|

and this:

|------Node0-----|
     |-Node1-|

For those systems, this interface has no meaning.  Given a page in the
shared-span areas, this interface provides no way to figure out which
node it is in.

If you want a non-portable hack that just works on one system, I'd
suggest parsing the existing firmware tables.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/