From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Harper Subject: Re: Can't boot guest with more than 3585MB when using large pages Date: Tue, 24 Mar 2009 16:57:46 -0500 Message-ID: <20090324215746.GH27104@us.ibm.com> References: <1237928806.6124.39.camel@bling> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm-devel To: Alex Williamson Return-path: Received: from e8.ny.us.ibm.com ([32.97.182.138]:45339 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753391AbZCXV5x (ORCPT ); Tue, 24 Mar 2009 17:57:53 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n2OLnabA023414 for ; Tue, 24 Mar 2009 17:49:36 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n2OLvmTL192416 for ; Tue, 24 Mar 2009 17:57:48 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n2OLvlBu018356 for ; Tue, 24 Mar 2009 17:57:47 -0400 Content-Disposition: inline In-Reply-To: <1237928806.6124.39.camel@bling> Sender: kvm-owner@vger.kernel.org List-ID: * Alex Williamson [2009-03-24 16:07]: > > On a 2.6.29, x86_64 host/guest, what's special about specifying a guest > size of -m 3586 when using -mem-path backed by hugetlbfs? 3585 works, > 3586 hangs here: > > ... > PCI-DMA: Using software bounce buffering for IO (SWIOTLB) > Placing 64MB software IO TLB between ffff880020000000 - ffff880024000000 > software IO TLB at phys 0x20000000 - 0x24000000 > Memory: 3504832k/4196352k available (2926k kernel code, 524740k absent, 166780k reserved, 1260k data, 496k init) > > I can back -mem-path by tmpfs or disk and it works fine. Also works > with no -mem-path, but it would obviously be nice to benefit from large > pages on big guests. The system has plenty of huge pages to back the > request, and booting with -mem-prealloc makes no difference. Tested on > latest git as of today. Thanks, I've seen this as well, haven't had a chance to dig into the issue yet either. Certainly can test patches if anyone has an idea of what's wrong here. -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx ryanh@us.ibm.com