Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263059AbUCMFt3 (ORCPT ); Sat, 13 Mar 2004 00:49:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263058AbUCMFt3 (ORCPT ); Sat, 13 Mar 2004 00:49:29 -0500 Received: from holomorphy.com ([207.189.100.168]:43016 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S263056AbUCMFt1 (ORCPT ); Sat, 13 Mar 2004 00:49:27 -0500 Date: Fri, 12 Mar 2004 21:49:10 -0800 From: William Lee Irwin III To: Andi Kleen Cc: Ray Bryant , lse-tech@lists.sourceforge.net, "linux-ia64@vger.kernel.org" , linux-kernel@vger.kernel.org Subject: Re: Hugetlbpages in very large memory machines....... Message-ID: <20040313054910.GA655@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Andi Kleen , Ray Bryant , lse-tech@lists.sourceforge.net, "linux-ia64@vger.kernel.org" , linux-kernel@vger.kernel.org References: <40528383.10305@sgi.com> <20040313034840.GF4638@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040313034840.GF4638@wotan.suse.de> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1072 Lines: 22 On Sat, Mar 13, 2004 at 04:48:40AM +0100, Andi Kleen wrote: > One drawback is that the out of memory handling is lot less nicer > than it was before - when you run out of hugepages you get SIGBUS > now instead of a ENOMEM from mmap. Maybe some prereservation would > make sense, but that would be somewhat harder. Alternatively > fall back to smaller pages if possible (I was told it isn't easily > possible on IA64) That's not entirely true. Whether it's feasible depends on how the MMU is used. The HPW (Hardware Pagetable Walker) and short mode of the VHPT insist upon pagesize being a per-region attribute, where regions are something like 60-bit areas of virtualspace, which is likely what they're referring to. The VHPT in long mode should be capable of arbitrary virtual placement (modulo alignment of course). -- wli - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/