From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757312Ab1INS3O (ORCPT ); Wed, 14 Sep 2011 14:29:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62719 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757261Ab1INS3M (ORCPT ); Wed, 14 Sep 2011 14:29:12 -0400 Date: Wed, 14 Sep 2011 14:29:02 -0400 From: Vivek Goyal To: Michael Holzheu Cc: Andrew Morton , ebiederm@xmission.com, mahesh@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Andrew Morton Subject: Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory Message-ID: <20110914182902.GA32658@redhat.com> References: <20110913132635.063397500@linux.vnet.ibm.com> <20110913132654.157278466@linux.vnet.ibm.com> <20110913145218.659f9e21.akpm@google.com> <1315990708.3367.14.camel@br98xy6r> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1315990708.3367.14.camel@br98xy6r> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 14, 2011 at 10:58:28AM +0200, Michael Holzheu wrote: > Hello Andrew, > > On Tue, 2011-09-13 at 14:52 -0700, Andrew Morton wrote: > > On Tue, 13 Sep 2011 15:26:37 +0200 > > Michael Holzheu wrote: > > [snip] > > > > --- a/arch/s390/include/asm/kexec.h > > > +++ b/arch/s390/include/asm/kexec.h > > > @@ -36,6 +36,9 @@ > > > /* Allocate one page for the pdp and the second for the code */ > > > #define KEXEC_CONTROL_PAGE_SIZE 4096 > > > > > > +/* Alignment of crashkernel memory */ > > > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE > > > > Why not make this unconditional, for all architectures which support > > hugepages? ie: > > > > #ifdef HPAGE_SIZE > > #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE > > #else > > #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE > > #endif > > > in include/linux/kexec.h? > > > > IOW, what are the compromises here? > > If we would do it that way, crashkernel memory on architectures that > support large pages but do not support unmapping of crashkernel memory > would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment > would be necessary in that case. > > If that is acceptable I have no problem to define that unconditional for > all architectures. Vivek what do you think? As PAGE_SIZE alignment is sufficient for rest of the architecture, I am fine with keeping it in arch dependent files. Thanks Vivek