From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fhbvP-0003vH-Sp for kexec@lists.infradead.org; Mon, 23 Jul 2018 14:35:01 +0000 Date: Mon, 23 Jul 2018 16:34:43 +0200 From: Michal Hocko Subject: Re: [PATCH v7 4/4] kexec_file: Load kernel at top of system RAM if required Message-ID: <20180723143443.GD18181@dhcp22.suse.cz> References: <20180718024944.577-1-bhe@redhat.com> <20180718024944.577-5-bhe@redhat.com> <20180718153326.b795e9ea7835432a56cd7011@linux-foundation.org> <20180719151753.GB7147@localhost.localdomain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180719151753.GB7147@localhost.localdomain> 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: Baoquan He Cc: nicolas.pitre@linaro.org, brijesh.singh@amd.com, devicetree@vger.kernel.org, airlied@linux.ie, linux-pci@vger.kernel.org, richard.weiyang@gmail.com, keith.busch@intel.com, jcmvbkbc@gmail.com, baiyaowei@cmss.chinamobile.com, kys@microsoft.com, frowand.list@gmail.com, dan.j.williams@intel.com, lorenzo.pieralisi@arm.com, sthemmin@microsoft.com, linux-nvdimm@lists.01.org, patrik.r.jakobsson@gmail.com, andy.shevchenko@gmail.com, linux-input@vger.kernel.org, gustavo@padovan.org, bp@suse.de, dyoung@redhat.com, vgoyal@redhat.com, thomas.lendacky@amd.com, haiyangz@microsoft.com, maarten.lankhorst@linux.intel.com, josh@joshtriplett.org, jglisse@redhat.com, robh+dt@kernel.org, seanpaul@chromium.org, bhelgaas@google.com, tglx@linutronix.de, yinghai@kernel.org, jonathan.derrick@intel.com, chris@zankel.net, monstr@monstr.eu, linux-parisc@vger.kernel.org, gregkh@linuxfoundation.org, dmitry.torokhov@gmail.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, ebiederm@xmission.com, devel@linuxdriverproject.org, Andrew Morton , fengguang.wu@intel.com, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net On Thu 19-07-18 23:17:53, Baoquan He wrote: > Kexec has been a formal feature in our distro, and customers owning > those kind of very large machine can make use of this feature to speed > up the reboot process. On uefi machine, the kexec_file loading will > search place to put kernel under 4G from top to down. As we know, the > 1st 4G space is DMA32 ZONE, dma, pci mmcfg, bios etc all try to consume > it. It may have possibility to not be able to find a usable space for > kernel/initrd. From the top down of the whole memory space, we don't > have this worry. I do not have the full context here but let me note that you should be careful when doing top-down reservation because you can easily get into hotplugable memory and break the hotremove usecase. We even warn when this is done. See memblock_find_in_range_node -- Michal Hocko SUSE Labs _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec