From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp02.in.ibm.com (e28smtp02.in.ibm.com [59.145.155.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp02.in.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 87200DE4CD for ; Wed, 7 Jan 2009 23:58:19 +1100 (EST) Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by e28smtp02.in.ibm.com (8.13.1/8.13.1) with ESMTP id n07CwB7A029341 for ; Wed, 7 Jan 2009 18:28:11 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id n07CuXId3903578 for ; Wed, 7 Jan 2009 18:26:33 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.13.1/8.13.3) with ESMTP id n07CwBST004440 for ; Wed, 7 Jan 2009 23:58:11 +1100 From: Chandru To: Dave Hansen Subject: Re: 2.6.28-rc9 panics with crashkernel=256M while booting Date: Wed, 7 Jan 2009 18:28:13 +0530 References: <200812241325.49404.chandru@in.ibm.com> <200901051919.52327.chandru@in.ibm.com> <1231173033.19452.190.camel@nimitz> In-Reply-To: <1231173033.19452.190.camel@nimitz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200901071828.13719.chandru@in.ibm.com> Cc: linuxppc-dev@ozlabs.org, Andrew Morton , Paul Mackerras , linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Monday 05 January 2009 22:00:33 Dave Hansen wrote: > OK, I had to think about this for a good, long time. That's bad. :) > > There are two things that we're dealing with here: "active regions" and > the NODE_DATA's. The if() you've pasted above resizes the reservation > so that it fits into the current active region. However, as you noted, > we haven't resized it so that it fits into the NODE_DATA() that we're > looking at. We call into the bootmem code, and BUG_ON(). > > The thing I don't like about this is that it might hide bugs in other > callers. This really is a ppc-specific thing and, although what you > wrote will fix the bug on ppc, it will probably cause someone in the > future to call reserve_bootmem_node() with too large a reservation and > get a silent failure (not reserving the requested size) back. > > We really do need to go take a hard look at the whole interaction > between lmb's, node active regions, and the NUMA code some day. It has > kinda grown to be a bit ungainly. > > How about we just consult the NODE_DATA() in > mark_reserved_regions_for_nid() instead of reserve_bootmem_node()? I don't know how you wanted NODE_DATA() to be consulted here. i.e before calling reserve_bootmem_node() should we have a condition if (PFN_UP(physbase+reserve_size) > node_end_pfn) then resize reserve_size again so that PFN_UP() will equate to node_end_pfn ?? end Also I was wondering if in reserve_bootmem_node() end = PFN_DOWN() ; will do.. With the recent changes from you that went into 2.6.28 stable (commit:a4c74ddd5ea3db53fc73d29c222b22656a7d05be), it worked on the system with PFN_DOWN(). Thanks, Chandru