From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752216Ab1IUFtt (ORCPT ); Wed, 21 Sep 2011 01:49:49 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:54852 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751883Ab1IUFts (ORCPT ); Wed, 21 Sep 2011 01:49:48 -0400 Message-ID: <4E797B55.20102@cn.fujitsu.com> Date: Wed, 21 Sep 2011 13:51:17 +0800 From: Lai Jiangshan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Stefano Stabellini CC: "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Tejun Heo , Yinghai Lu , Stephen Wilson Subject: Re: [PATCH x86,mm] fix pgt_buf_end when memory hotplug References: <4E688C03.7080608@cn.fujitsu.com> In-Reply-To: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-09-21 13:48:08, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-09-21 13:48:22, Serialize complete at 2011-09-21 13:48:22 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/08/2011 11:21 PM, Stefano Stabellini wrote: > On Thu, 8 Sep 2011, Lai Jiangshan wrote: >> >> When I test memory hotplug, such message is always outputted when hot-adding >> a memory block: >> >> initial kernel pagetable allocation wasted ffffffffffffffff pages > > I take you are using tip/x86/mm, because that is the only branch that > contains that warning. No, I was using tip/master. Thanks, Lai > > >> This message comes from init_memory_mapping(), it shows "pgt_buf_end" is >> incorrect here, and I found it was caused by alloc_low_page(). >> >> Signed-off-by: Lai Jiangshan >> --- >> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c >> index bbaaa00..e138e0a 100644 >> --- a/arch/x86/mm/init_64.c >> +++ b/arch/x86/mm/init_64.c >> @@ -317,7 +317,7 @@ void __init cleanup_highmap(void) >> >> static __ref void *alloc_low_page(unsigned long *phys) >> { >> - unsigned long pfn = pgt_buf_end++; >> + unsigned long pfn; >> void *adr; >> >> if (after_bootmem) { >> @@ -327,6 +327,7 @@ static __ref void *alloc_low_page(unsigned long *phys) >> return adr; >> } >> >> + pfn = pgt_buf_end++; >> if (pfn >= pgt_buf_top) >> panic("alloc_low_page: ran out of memory"); > > > This patch makes sense to me. It would also make sense to print the > "allocation wasted" warning only if (!after_bootmem). > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >