linux-kernel - Re: [PATCH 00/18] Make common x86 arch area for i386 and x86_64

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: <20070316.134718.95058720.davem@davemloft.net>
Date:	Fri, 16 Mar 2007 13:47:18 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	clameter@....com
Cc:	andi@...stfloor.org, rostedt@...dmis.org,
	torvalds@...ux-foundation.org, mbligh@...igh.org, mingo@...e.hu,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	chrisw@...s-sol.org, rusty@...tcorp.com.au, glommer@...il.com
Subject: Re: [PATCH 00/18] Make common x86 arch area for i386 and x86_64 -
 Take 2

From: Christoph Lameter <clameter@....com>
Date: Fri, 16 Mar 2007 13:15:38 -0700 (PDT)

> On Fri, 16 Mar 2007, Andi Kleen wrote:
> 
> > > x86_64 is going to acquire more functionality that will not be available 
> > > for i386. We plan f.e. to add virtual memmap support for x86_64. Virtual 
> > 
> > What advantage would that have over the current setup?
> > We already should handle holes between nodes reasonably efficiently
> > and with nonlinear memory even holes inside nodes shouldn't be a problem.
> 
> It is primarily a performance improvement since the sparsemem table 
> lookups would no longer be necessary and it also streamlines other 
> frequent cacheline uses. These page -> page_struct and vice versa 
> operations are key to the performance of various subsystem among them 
> the slab allocator.

If you set the bit range small enough and don't use sparsemem-extreme,
the cost is extremely low considering the flexibility you obtain.

There are always going to be holes on large systems, there isn't
really a way to avoid this given how addressing is done on those
machines.
-
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/