From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UI64H-0005Yr-Ow for kexec@lists.infradead.org; Tue, 19 Mar 2013 23:35:46 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <20130316040003.15064.62308.stgit@localhost6.localdomain6> <20130316040132.15064.42257.stgit@localhost6.localdomain6> <878v5jqf5e.fsf@xmission.com> <20130319212244.GE3872@redhat.com> Date: Tue, 19 Mar 2013 16:35:36 -0700 In-Reply-To: <20130319212244.GE3872@redhat.com> (Vivek Goyal's message of "Tue, 19 Mar 2013 17:22:44 -0400") Message-ID: <87boafhsjb.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: [PATCH v3 08/21] vmcore: copy non page-size aligned head and tail pages in 2nd kernel 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: Vivek Goyal Cc: kexec@lists.infradead.org, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, lisa.mitchell@hp.com, HATAYAMA Daisuke , kumagai-atsushi@mxc.nes.nec.co.jp, zhangyanfei@cn.fujitsu.com, akpm@linux-foundation.org, cpw@sgi.com Vivek Goyal writes: > Are you saying that some parts of the vmcore file will support mmap() and > others will not. If yes, how would a user know which parts of file are > mappable and which are not. I think I answered this in another email in my review but I will reanswer here. There is absolutely no need to copy pages. We can round up the mapping to the nearest full page. Mmap already does that today for files so it isn't even odd. Which only leaves the headers and notes as potentially unmmapable. That is more of a policy decision, and a decision on where we want to spend memory. Rounding ELF notes to mutliples of PAGE_SIZE from a perspective of memory usage seems pretty terrible taking memory usage up an order of magnitude. Eric _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec