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From: Michal Hocko <mhocko@kernel•org>
To: Baoquan He <bhe@redhat•com>
Cc: Andrew Morton <akpm@linux-foundation•org>,
	linux-kernel@vger•kernel.org, robh+dt@kernel•org,
	dan.j.williams@intel•com, nicolas.pitre@linaro•org,
	josh@joshtriplett•org, fengguang.wu@intel•com, bp@suse•de,
	andy.shevchenko@gmail•com, patrik.r.jakobsson@gmail•com,
	airlied@linux•ie, kys@microsoft•com, haiyangz@microsoft•com,
	sthemmin@microsoft•com, dmitry.torokhov@gmail•com,
	frowand.list@gmail•com, keith.busch@intel•com,
	jonathan.derrick@intel•com, lorenzo.pieralisi@arm•com,
	bhelgaas@google•com, tglx@linutronix•de, brijesh.singh@amd•com,
	jglisse@redhat•com, thomas.lendacky@amd•com,
	gregkh@linuxfoundation•org, baiyaowei@cmss•chinamobile.com,
	richard.weiyang@gmail•com, devel@linuxdriverproject•org,
	linux-input@vger•kernel.org, linux-nvdimm@lists•01.org,
	devicetree@vger•kernel.org, linux-pci@vger•kernel.org,
	ebiederm@xmission•com, vgoyal@redhat•com, dyoung@redhat•com,
	yinghai@kernel•org, monstr@monstr•eu, davem@davemloft•net,
	chris@zankel•net, jcmvbkbc@gmail•com, gustavo@padovan•org,
	maarten.lankhorst@linux•intel.com, seanpaul@chromium•org,
	linux-parisc@vger•kernel.org, linuxppc-dev@lists•ozlabs.org,
	kexec@lists•infradead.org
Subject: Re: [PATCH v7 4/4] kexec_file: Load kernel at top of system RAM if required
Date: Mon, 23 Jul 2018 16:34:43 +0200	[thread overview]
Message-ID: <20180723143443.GD18181@dhcp22.suse.cz> (raw)
In-Reply-To: <20180719151753.GB7147@localhost.localdomain>

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

  parent reply	other threads:[~2018-07-23 14:34 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-18  2:49 [PATCH v7 0/4] resource: Use list_head to link sibling resource Baoquan He
2018-07-18  2:49 ` [PATCH v7 1/4] resource: Move reparent_resources() to kernel/resource.c and make it public Baoquan He
2018-07-18 16:36   ` Andy Shevchenko
2018-07-18 16:37     ` Andy Shevchenko
2018-07-19 15:18       ` Baoquan He
2018-07-18  2:49 ` [PATCH v7 2/4] resource: Use list_head to link sibling resource Baoquan He
2018-07-18  2:49 ` [PATCH v7 3/4] resource: add walk_system_ram_res_rev() Baoquan He
2018-07-18  2:49 ` [PATCH v7 4/4] kexec_file: Load kernel at top of system RAM if required Baoquan He
2018-07-18 22:33   ` Andrew Morton
2018-07-19 15:17     ` Baoquan He
2018-07-19 19:44       ` Andrew Morton
2018-07-25  2:21         ` Baoquan He
2018-07-23 14:34       ` Michal Hocko [this message]
2018-07-25  6:48         ` Baoquan He
2018-07-26 12:59           ` Michal Hocko
2018-07-26 13:09             ` Baoquan He
2018-07-26 13:12               ` Michal Hocko
2018-07-26 13:14                 ` Michal Hocko
2018-07-26 13:37                   ` Baoquan He
2018-07-26 14:01                     ` Michal Hocko
2018-07-26 15:10                       ` Baoquan He

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