From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q5BNuFgw152870 for ; Mon, 11 Jun 2012 18:56:15 -0500 Received: from ipmail06.adl2.internode.on.net (ipmail06.adl2.internode.on.net [150.101.137.129]) by cuda.sgi.com with ESMTP id to9XcycVBQitco23 for ; Mon, 11 Jun 2012 16:56:14 -0700 (PDT) Date: Tue, 12 Jun 2012 09:56:12 +1000 From: Dave Chinner Subject: Re: block sizes > 4K ?? possible w/large page support? Message-ID: <20120611235612.GF22848@dastard> References: <4FD5643F.5070801@tlinx.org> <20120611132932.GA18432@andromeda.usersys.redhat.com> <4FD606C1.1070103@hardwarefreak.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4FD606C1.1070103@hardwarefreak.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Stan Hoeppner Cc: xfs@oss.sgi.com On Mon, Jun 11, 2012 at 09:54:57AM -0500, Stan Hoeppner wrote: > On 6/11/2012 8:29 AM, Carlos Maiolino wrote: > > > The maximum block size of a XFS filesystem is 64kiB. But in linux it's limited > > to the PAGE_SIZE value. > > Correct. > > > so, on x86 architectures, the maximum block size is > > 4kiB. > > Not entirely correct. Since ~1996, 16 years ago, PPro and higher 32bit > CPUs with PSE/PSE36 support pages of 4MB, or 2MB with PAE enabled. > > x86-64 CPUs in long mode also support a 2MB page size. But the problem > of internal fragmentation may outweigh the TLB and other benefits of > these very large pages. I'm not an MM dev so I can't elaborate further. > There may be other issues. > > > although it could benefit from a 16kiB page size, you'll need to be running an > > operating system which supports this page size value. > > And AFAIK the kernel MM team doesn't have x86 2MB pages on their radar. > Or do they? Been supported for a few of years now in one form or another. google for "transparent huge pages"..... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs