From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752419Ab3K2EZc (ORCPT ); Thu, 28 Nov 2013 23:25:32 -0500 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:52564 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001Ab3K2EZ2 convert rfc822-to-8bit (ORCPT ); Thu, 28 Nov 2013 23:25:28 -0500 From: Atsushi Kumagai To: HATAYAMA Daisuke CC: "bhe@redhat.com" , "tom.vaden@hp.com" , "kexec@lists.infradead.org" , "ptesarik@suse.cz" , "linux-kernel@vger.kernel.org" , "lisa.mitchell@hp.com" , "vgoyal@redhat.com" , "anderson@redhat.com" , "ebiederm@xmission.com" , "jingbai.ma@hp.com" Subject: Re: [PATCH 0/3] makedumpfile: hugepage filtering for vmcore dump Thread-Topic: [PATCH 0/3] makedumpfile: hugepage filtering for vmcore dump Thread-Index: Ac7snBnC1kksR0zQtUinUJVDkNQRF///lTGA//9a6ZA= Date: Fri, 29 Nov 2013 04:23:19 +0000 Message-ID: <0910DD04CBD6DE4193FCF86B9C00BE971C86DC@BPXM01GP.gisp.nec.co.jp> References: <0910DD04CBD6DE4193FCF86B9C00BE971C855E@BPXM01GP.gisp.nec.co.jp> <5298084B.7060603@jp.fujitsu.com> In-Reply-To: <5298084B.7060603@jp.fujitsu.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.21.40.240] Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2013/11/29 12:24:45, kexec wrote: > (2013/11/29 12:02), Atsushi Kumagai wrote: > > On 2013/11/28 16:50:21, kexec wrote: > >>>> ping, in case you overlooked this... > >>> > >>> Sorry for the delayed response, I prioritize the release of v1.5.5 now. > >>> > >>> Thanks for your advice, check_cyclic_buffer_overrun() should be fixed > >>> as you said. In addition, I'm considering other way to address such case, > >>> that is to bring the number of "overflowed pages" to the next cycle and > >>> exclude them at the top of __exclude_unnecessary_pages() like below: > >>> > >>> /* > >>> * The pages which should be excluded still remain. > >>> */ > >>> if (remainder >= 1) { > >>> int i; > >>> unsigned long tmp; > >>> for (i = 0; i < remainder; ++i) { > >>> if (clear_bit_on_2nd_bitmap_for_kernel(pfn + i)) { > >>> pfn_user++; > >>> tmp++; > >>> } > >>> } > >>> pfn += tmp; > >>> remainder -= tmp; > >>> mem_map += (tmp - 1) * SIZE(page); > >>> continue; > >>> } > >>> > >>> If this way works well, then aligning info->buf_size_cyclic will be > >>> unnecessary. > >>> > >> > >> I selected the current implementation of changing cyclic buffer size becuase > >> I thought it was simpler than carrying over remaining filtered pages to next cycle > >> in that there was no need to add extra code in filtering processing. > >> > >> I guess the reason why you think this is better now is how to detect maximum order of > >> huge page is hard in some way, right? > > > > The maximum order will be gotten from HUGETLB_PAGE_ORDER or HPAGE_PMD_ORDER, > > so I don't say it's hard. However, the carrying over method doesn't depend on > > such kernel symbols, so I think it's robuster. > > > > Then, it's better to remove check_cyclic_buffer_overrun() and rewrite part of free page > filtering in __exclude_unnecessary_pages(). Could you do that too? Sure, I'll modify it too. Thanks Atsushi Kumagai