Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757349AbYH1Xh2 (ORCPT ); Thu, 28 Aug 2008 19:37:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755272AbYH1XhO (ORCPT ); Thu, 28 Aug 2008 19:37:14 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35462 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755166AbYH1XhM (ORCPT ); Thu, 28 Aug 2008 19:37:12 -0400 Date: Fri, 29 Aug 2008 08:35:28 +0900 From: KOSAKI Motohiro To: Hugh Dickins Subject: Re: [PATCH] coredump_filter: add hugepage core dumping Cc: kosaki.motohiro@jp.fujitsu.com, Kawai Hidehiro , William Irwin , Adam Litke , LKML , Andrew Morton In-Reply-To: References: <20080828142352.6ABC.KOSAKI.MOTOHIRO@jp.fujitsu.com> Message-Id: <20080829082832.3C1D.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 34 Hi > > I think VM_RESERVED default dumping bahavior is good, > > then I'd like to add coredump_filter mask. > > > > This patch doesn't change dafault behavior. > > This seems very reasonable to me > (though I've little use for coredumps or hugepages myself). Thanks a lot. > One caution though: how well does it behave when coredumping a large > area of hugepages which have not actually been instantiated prior to > the coredump? We have that funny FOLL_ANON ZERO_PAGE code in > follow_page() to avoid wasting memory on large uninstantiated anon > areas, but hugepages won't go that way. If the dump hangs waiting for > memory to be freed, or OOMkills other processes, that wouldn't be good; > whereas if hugepage reservations (I've not followed what happens with > them) or whatever just make it skip when no more, that should be okay. I think hugepage reservation pages always exist when hugepage COW happend. Then, hugepage access never cause try_to_free_pages() nor OOM. Adam, if I talk lie, please tell us truth. -- 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/