linux-kernel - Re: [PATCH 0/8] Create ZONE_MOVABLE to partition memory between movable and non-movable 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: <Pine.LNX.4.64.0701260756580.6141@schroedinger.engr.sgi.com>
Date:	Fri, 26 Jan 2007 08:01:07 -0800 (PST)
From:	Christoph Lameter <clameter@....com>
To:	Mel Gorman <mel@....ul.ie>
cc:	Andrew Morton <akpm@...l.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Christoph Lameter <clameter@...r.sgi.com>
Subject: Re: [PATCH 0/8] Create ZONE_MOVABLE to partition memory between
 movable and non-movable pages

On Fri, 26 Jan 2007, Mel Gorman wrote:

> I haven't thought about it much so I probably am missing something. The major
> difference I see is when only one zone is present. In that case, a number of
> loops presumably get optimised away and the behavior is very different
> (presumably better although you point out no figures exist to prove it). Where
> there are two or more zones, the code paths should be similar whether there
> are 2, 3 or 4 zones present.

The balancing of allocations between zones is becoming unnecessary. Also 
in a NUMA system we then have zone == node which allows for a series of 
simplifications.

> As the common platforms will always have more than one zone, it'll be heavily
> tested and I'm guessing that distros are always going to have to ship kernels
> with ZONE_DMA for the devices that require it. The only platform I see that
> may have problems at the moment is IA64 which looks like the only platform
> that can have one and only one zone. I am guessing that Christoph will catch
> problems here fairly quickly although a non-optional ZONE_MOVABLE would throw
> a spanner into the works somewhat.

There are 6 platforms that have only one zone. These are not major 
platforms. In order for major platforms to go to a single zone in general 
we would have to implement a generic mechanism to do an allocation where 
one can specify the memory boundaries. Many DMA engines have different
limitations from what ZONE_DMA and ZONE_DMA32 can provide. If such a 
scheme would be implemented then those would be able to utilize memory 
better and the amount of bounce buffers would be reduced.
-
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/