From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 31F218D0040 for ; Mon, 28 Mar 2011 11:56:34 -0400 (EDT) Received: from d01dlp02.pok.ibm.com (d01dlp02.pok.ibm.com [9.56.224.85]) by e9.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p2SFTJpq015501 for ; Mon, 28 Mar 2011 11:29:19 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 554DC6E803C for ; Mon, 28 Mar 2011 11:56:32 -0400 (EDT) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p2SFtVja108128 for ; Mon, 28 Mar 2011 11:55:39 -0400 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p2SFtTSJ009665 for ; Mon, 28 Mar 2011 09:55:30 -0600 Subject: Re: [PATCH] xen/balloon: Memory hotplug support for Xen balloon driver From: Dave Hansen In-Reply-To: <20110328094757.GJ13826@router-fw-old.local.net-space.pl> References: <20110328094757.GJ13826@router-fw-old.local.net-space.pl> Content-Type: text/plain; charset="ISO-8859-1" Date: Mon, 28 Mar 2011 08:55:27 -0700 Message-ID: <1301327727.31700.8354.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Kiper Cc: ian.campbell@citrix.com, akpm@linux-foundation.org, andi.kleen@intel.com, haicheng.li@linux.intel.com, fengguang.wu@intel.com, jeremy@goop.org, konrad.wilk@oracle.com, dan.magenheimer@oracle.com, v.tolstov@selfip.ru, pasik@iki.fi, wdauchy@gmail.com, rientjes@google.com, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, 2011-03-28 at 11:47 +0200, Daniel Kiper wrote: > > +static enum bp_state reserve_additional_memory(long credit) > +{ > + int nid, rc; > + u64 start; > + unsigned long balloon_hotplug = credit; > + > + start = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); > + balloon_hotplug = (balloon_hotplug & PAGE_SECTION_MASK) + PAGES_PER_SECTION; > + nid = memory_add_physaddr_to_nid(start); Is the 'balloon_hotplug' calculation correct? I _think_ you're trying to round up to the SECTION_SIZE_PAGES. But, if 'credit' was already section-aligned I think you'll unnecessarily round up to the next SECTION_SIZE_PAGES boundary. Should it just be: balloon_hotplug = ALIGN(balloon_hotplug, PAGES_PER_SECTION); You might also want to consider some nicer units for those suckers. 'start_paddr' is _much_ easier to grok than 'start', for instance. -- Dave -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org