From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UIZqD-0004pp-3i for kexec@lists.infradead.org; Thu, 21 Mar 2013 07:23:17 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <87txo5bxk4.fsf@xmission.com> <20130321.122501.82758179.d.hatayama@jp.fujitsu.com> <8738vp75cy.fsf@xmission.com> <20130321.151428.393714972.d.hatayama@jp.fujitsu.com> Date: Thu, 21 Mar 2013 00:22:59 -0700 In-Reply-To: <20130321.151428.393714972.d.hatayama@jp.fujitsu.com> (HATAYAMA Daisuke's message of "Thu, 21 Mar 2013 15:14:28 +0900 (JST)") Message-ID: <87y5dhw71o.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: [PATCH v3 18/21] vmcore: check if vmcore objects satify mmap()'s page-size boundary requirement List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: HATAYAMA Daisuke Cc: kexec@lists.infradead.org, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, lisa.mitchell@hp.com, kumagai-atsushi@mxc.nes.nec.co.jp, zhangyanfei@cn.fujitsu.com, akpm@linux-foundation.org, cpw@sgi.com, vgoyal@redhat.com HATAYAMA Daisuke writes: > OK, rigorously, suceess or faliure of the requested free pages > allocation depends on actual memory layout at the 2nd kernel boot. To > increase the possibility of allocating memory, we have no method but > reserve more memory for the 2nd kernel now. Good enough. If there are fragmentation issues that cause allocation problems on larger boxes we can use vmalloc and remap_vmalloc_range, but we certainly don't need to start there. Especialy as for most 8 or 16 core boxes we are talking about a 4KiB or an 8KiBP allocation. Aka order 0 or order 1. Adding more memory is also useful. It is important in general to keep the amount of memory needed for the kdump kernel low. Eric _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec