Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933860AbbGVKLh (ORCPT ); Wed, 22 Jul 2015 06:11:37 -0400 Received: from 8bytes.org ([81.169.241.247]:50279 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933154AbbGVKLf (ORCPT ); Wed, 22 Jul 2015 06:11:35 -0400 Date: Wed, 22 Jul 2015 12:11:33 +0200 From: Joerg Roedel To: Yinghai Lu Cc: Baoquan He , Dave Young , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Andrew Morton , Jiri Kosina , Vivek Goyal , Linux Kernel Mailing List Subject: Re: [PATCH v2] Do not reserve crashkernel high memory if crashkernel low memory reserving failed Message-ID: <20150722101133.GH10969@8bytes.org> References: <1437304064-9916-1-git-send-email-bhe@redhat.com> <20150719145320.GB9968@dhcp-17-102.nay.redhat.com> <20150721073123.GA30649@dhcp-129-220.nay.redhat.com> <20150721075011.GC16747@dhcp-128-28.nay.redhat.com> <20150721082343.GC30649@dhcp-129-220.nay.redhat.com> <20150721085846.GA23020@dhcp-128-28.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 1209 Lines: 33 On Tue, Jul 21, 2015 at 12:22:53PM -0700, Yinghai Lu wrote: > On Tue, Jul 21, 2015 at 1:58 AM, Baoquan He wrote: > > > Maybe system which don't need low memory is rare, only for testing? > > No, it is not rare. > > All recent intel based systems with iommu support does not need low. All Intel-IOMMU systems have the iommu disabled by default (at least that is the default in most distros). So low memory is definitly needed by those systems too. > that reserve 256M low always. and those 256M get wasted. > > That commit should only be used to workaround some systems that > have partial iommu support. We currently lack the infrastructure for that, but I am happy to review patches. How about letting subsystems announce their need for low crash-kernel memory and allocate based on that? The subsystems (like iommu or swiotlb code, for example) could even announce how much memory they need and we base our allocation on that. Joerg -- 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/