From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 13 Sep 2006 11:00:24 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH 0/8] Optional ZONE_DMA V1 In-Reply-To: <20060913174948.GA6533@sgi.com> Message-ID: References: <20060911222729.4849.69497.sendpatchset@schroedinger.engr.sgi.com> <1158046205.2992.1.camel@laptopd505.fenrus.org> <4507D4EE.4060501@sgi.com> <20060913174948.GA6533@sgi.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Jack Steiner Cc: Jes Sorensen , Arjan van de Ven , linux-mm@kvack.org, Nick Piggin , Christoph Hellwig , linux-ia64@vger.kernel.org, Marcelo Tosatti , Martin Bligh , KAMEZAWA Hiroyuki , Andi Kleen List-ID: On Wed, 13 Sep 2006, Jack Steiner wrote: > - will any IA64 platform require that ZONE_DMA be enabled (I think > the answer is "yes") I think that still remains to be discussed. Today there are various means to get around address restrictions. > - if ZONE_DMA is enabled, ALTIX will still use only 1 zone. In your > statement above, you say that disabling ZONE_DMA save 1M cpu > structures. If ZONE_DMA is enabled, will these 1M structure be allocated > on SN even though they are not needed? That has always been the case. In SLES9 and SLES10 we are using 1/4th of the pagesets. Having no ZONE_DMA provides additional benefits besides saving memory. The VM balancing of allocations within a node becomes not necessary and various VM optimization can be performed. Loops are unrolled. Less zones have to be processed for draining / vm counter updates etc etc. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org