From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753308AbZHLG4J (ORCPT ); Wed, 12 Aug 2009 02:56:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753106AbZHLG4J (ORCPT ); Wed, 12 Aug 2009 02:56:09 -0400 Received: from hera.kernel.org ([140.211.167.34]:35344 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753051AbZHLG4H (ORCPT ); Wed, 12 Aug 2009 02:56:07 -0400 Message-ID: <4A826785.4000509@kernel.org> Date: Wed, 12 Aug 2009 15:56:05 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.22 (X11/20090605) MIME-Version: 1.0 To: "Yu, Fenghua" CC: "Luck, Tony" , "'lkml'" , "'linux-arch@vger.kernel.org'" , "'linux-ia64@vger.kernel.org'" Subject: Re: [RFC PATCH] ia64: convert to dynamic percpu allocator References: <4A65B0AB.5000608@kernel.org> <4A663DC7.4060600@kernel.org> <4A695897.2020902@kernel.org> In-Reply-To: X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Wed, 12 Aug 2009 06:56:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yu, Fenghua wrote: >> Yu, Fenghua wrote: >> >>> After cloning from >>> git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu.git, kernel >>> built with CONFIG_DISCONTIGMEM=y boots ok. >>> >>> After pulling from review-ia64, kernel built with >>> CONFIG_DISCONTIGMEM=y can not boot on ia64. After loading kernel and >>> initrd, system hangs and doesn't show anything on serial port. >> Heh, I didn't really expect it to work that easily either. The code >> builds but is completely untested (I can't test them). Can you try to >> track it down? Serial console should be up and running at that point, >> no? >> >> Thanks. > > IA64 kernel boots hit this in mm/percpu.c > BUG_ON(ai->unit_size < size_sum); > ai->unit_size is PERCPU_PAGE_SIZE which is 64K on IA64. size_sum is > relatively smaller than 64K. > > Will you define PERCPU_DYNAMIC_RESERVE and PERCPU_MODULE_RESERVE as > PAGE_SIZE or the bigger one between the current definition and > PAGE_SIZE? Hmmm... * Is ai->reserved_size necessary for ia64? This is necessary if there's linking range restriction when loading modules. ai->reserved_size guarantees that all static module percpu variables are allocated in the first chunk which will be in the linear address range and very close to __per_cpu_start. If ai->reserved_size is not set, these areas are likely to end up high in the vmalloc area. For example, x86_64 assumes 32bit relocations should be enough to link module symbols and thus needs to set reserved_size but x86_32 can link to the whole 32bit space and thus can leave reserved_size at zero. * After determining the above, we can set ai->dyn_size to be ai->dyn_size = min(ai->unit_size - ai->static_size - ai->reserved_size, PERCPU_DYNAMIC_RESERVE); Would the above work? > Even with the above PAGE_SIZE changes, the kernel still reports > warning from 952: WARN_ON(chunk->immutable) and then panic. Hah... strange. Can you please attach full boot log? This is dicontig configuration, right? Thanks. -- tejun