From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id B1EBE8D0040 for ; Thu, 31 Mar 2011 16:33:46 -0400 (EDT) Received: from d01dlp01.pok.ibm.com (d01dlp01.pok.ibm.com [9.56.224.56]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p2VKD1ws010073 for ; Thu, 31 Mar 2011 16:13:01 -0400 Received: from d01relay01.pok.ibm.com (d01relay01.pok.ibm.com [9.56.227.233]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 9035938C803C for ; Thu, 31 Mar 2011 16:33:37 -0400 (EDT) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay01.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p2VKXiIU391940 for ; Thu, 31 Mar 2011 16:33:44 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p2VKXfTW019223 for ; Thu, 31 Mar 2011 16:33:44 -0400 Subject: Re: [PATCH 04/12] mm: alloc_contig_freed_pages() added From: Dave Hansen In-Reply-To: <20110331192429.GD14441@home.goodmis.org> References: <1301577368-16095-1-git-send-email-m.szyprowski@samsung.com> <1301577368-16095-5-git-send-email-m.szyprowski@samsung.com> <1301587083.31087.1032.camel@nimitz> <20110331192429.GD14441@home.goodmis.org> Content-Type: text/plain; charset="ISO-8859-1" Date: Thu, 31 Mar 2011 13:33:39 -0700 Message-ID: <1301603619.31087.1203.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Steven Rostedt Cc: Marek Szyprowski , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, Michal Nazarewicz , Kyungmin Park , Andrew Morton , KAMEZAWA Hiroyuki , Ankita Garg , Daniel Walker , Johan MOSSBERG , Mel Gorman , Pawel Osciak On Thu, 2011-03-31 at 15:24 -0400, Steven Rostedt wrote: > On Thu, Mar 31, 2011 at 08:58:03AM -0700, Dave Hansen wrote: > > On Thu, 2011-03-31 at 15:16 +0200, Marek Szyprowski wrote: > > > > > > +unsigned long alloc_contig_freed_pages(unsigned long start, unsigned long end, > > > + gfp_t flag) > > > +{ > > > + unsigned long pfn = start, count; > > > + struct page *page; > > > + struct zone *zone; > > > + int order; > > > + > > > + VM_BUG_ON(!pfn_valid(start)); > > > > This seems kinda mean. Could we return an error? I understand that > > this is largely going to be an early-boot thing, but surely trying to > > punt on crappy input beats a full-on BUG(). > > > > if (!pfn_valid(start)) > > return -1; > > But still keep the warning? > > if (WARN_ON(!pfn_valid(start)) > return -1; Sure. You might also want to make sure you're respecting __GFP_NOWARN if you're going to do that, or maybe just warn once per boot. -- 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