Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263594AbUDOStI (ORCPT ); Thu, 15 Apr 2004 14:49:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263574AbUDOSqP (ORCPT ); Thu, 15 Apr 2004 14:46:15 -0400 Received: from fmr03.intel.com ([143.183.121.5]:12696 "EHLO hermes.sc.intel.com") by vger.kernel.org with ESMTP id S263117AbUDOSnu (ORCPT ); Thu, 15 Apr 2004 14:43:50 -0400 Message-Id: <200404151842.i3FIguF09326@unix-os.sc.intel.com> From: "Chen, Kenneth W" To: "Chen, Kenneth W" , "'David Gibson'" Cc: , , , , "'Andy Whitcroft'" , "'Andrew Morton'" Subject: RE: hugetlb demand paging patch part [0/3] Date: Thu, 15 Apr 2004 11:42:55 -0700 X-Mailer: Microsoft Office Outlook, Build 11.0.5510 In-Reply-To: <7A4826DE8867D411BAB8009027AE9EB91DB42C83@scsmsx401.sc.intel.com> Thread-Index: AcQi6pjtEdGy/DvtQ9m6bS2olrTMVgAIH/rAAAMKAOA= X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1942 Lines: 43 >>>> Chen, Kenneth W wrote on Thursday, April 15, 2004 10:08 AM > >>>> David Gibson wrote on Wednesday, April 14, 2004 11:43 PM > > > > > > Some caveats: I don't have sh and sparc64 hardware to test. But hugetlb > > > code in these two arch looked like a triplet twin of x86 code. So I'm > > > pretty sure it will work right out of box. I've monkeyed around with > > > ppc64 code and after a while I realized it should be left for the experts. > > > I'm sure there are plenty ppc64 developers out there that can get it done > > > in no time. > > > > To the extent that I understand your patches, it shouldn't be that > > hard to adapt for ppc64, with one caveat: on ppc64, unlike the other > > hugepage archs, the format of hugepage PTEs is not identical to the > > format of normal PTEs. So to do this for ppc64, the generic parts of > > your code will need to use a hugepte_t instead of pte_t - it can be > > typedeffed to pte_t on archs other than ppc64. Likewise there will > > need to be hugepte_none() and so forth macros. > > I think it would be cleaner if ppc64 change its format instead of changing > 4 other arch to accommodate ppc64. By the way, why do you need to special > typedef hugepte_t? pte for huge page aren't anything special on all other > arches. Again, I'm not an expert on ppc64, but this look suspicious to me: arch/ppc64/mm/hugetlbpage.c /* HugePTE layout: * * 31 30 ... 15 14 13 12 10 9 8 7 6 5 4 3 2 1 0 * PFN>>12..... - - - - - - HASH_IX.... 2ND HASH RW - HG=1 */ #define HUGEPTE_SHIFT 15 17 bits for pfn? It looks to me that huge page on ppc64 will break on system with more than 2 Terabyte of physical memory. - 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/