Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964986AbVJ0HwV (ORCPT ); Thu, 27 Oct 2005 03:52:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964987AbVJ0Hv5 (ORCPT ); Thu, 27 Oct 2005 03:51:57 -0400 Received: from mail6.hitachi.co.jp ([133.145.228.41]:39918 "EHLO mail6.hitachi.co.jp") by vger.kernel.org with ESMTP id S964985AbVJ0Hvy (ORCPT ); Thu, 27 Oct 2005 03:51:54 -0400 Date: Thu, 27 Oct 2005 16:45:58 +0900 (JST) Message-Id: <20051027.164558.92586706.noboru.obata.ar@hitachi.com> To: indou.takao@soft.fujitsu.com Cc: akpm@osdl.org, hyoshiok@miraclelinux.com, linux-kernel@vger.kernel.org Subject: Re: Linux Kernel Dump Summit 2005 From: OBATA Noboru In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1994 Lines: 49 On Wed, 19 Oct 2005, Takao Indoh wrote: > > > > Could you briefly explain the implementation of partial dump in > > diskdump for those who are not familiar with it? > > > > - Levels of partial dump (supported page categories) > > - How to indentify the category (kernel data structure used) > > Ok. > Partial dump of diskdump defines 5 filters. > > #define DUMP_EXCLUDE_CACHE 0x00000001 /* Exclude LRU & SwapCache pages*/ > #define DUMP_EXCLUDE_CLEAN 0x00000002 /* Exclude all-zero pages */ > #define DUMP_EXCLUDE_FREE 0x00000004 /* Exclude free pages */ > #define DUMP_EXCLUDE_ANON 0x00000008 /* Exclude Anon pages */ > #define DUMP_SAVE_PRIVATE 0x00000010 /* Save private pages */ > DUMP_EXCLUDE_FREE has some risks. If this filter is enable, diskdump > scans free page linked lists. If the list is corrupt, diskdump may hang. > Therefore, I always use level-19 (EXCLUDE_CACHE & EXCLUDE_CLEAN & > SAVE_PRIVATE). > > DUMP_EXCLUDE_CACHE reduces dump size effectively when file caches on > memory are big. I don't use DUMP_EXCLUDE_ANON because user data(user > stack, thread stack, mutex, etc.) is sometimes needed to investigate > dump. > DUMP_SAVE_PRIVATE is needed for filesystem. Filesystem (journal) uses > PG_private pages, so these pages is necessary to investigate > trouble of filesystem. Thank you for filters' description as well as the recommended filter combination. I'm just wondering the use of DUMP_EXCLUDE_CLEAN. When a zero page is excluded from a dump, how people know? What I'm afraid is that people would see an error (e.g., no such page in a dump) in analyzing such a dump and be confused why. Because it is a cache, or zero-cleared, or, ...? Any ideas? Regards, -- OBATA Noboru (noboru.obata.ar@hitachi.com) - 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/