From: Tang Chen <tangchen@cn.fujitsu.com>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: Jianguo Wu <wujianguo@huawei.com>,
akpm@linux-foundation.org, rientjes@google.com,
len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org,
cl@linux.com, minchan.kim@gmail.com,
kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com,
wency@cn.fujitsu.com, hpa@zytor.com, linfeng@cn.fujitsu.com,
laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org,
glommer@parallels.com, x86@kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org,
cmetcalf@tilera.com, sparclinux@vger.kernel.org
Subject: Re: [PATCH v6 00/15] memory-hotplug: hot-remove physical memory
Date: Fri, 01 Feb 2013 01:57:13 +0000 [thread overview]
Message-ID: <510B20F9.10408@cn.fujitsu.com> (raw)
In-Reply-To: <1359682576.3574.1.camel@kernel>
On 02/01/2013 09:36 AM, Simon Jeons wrote:
> On Fri, 2013-02-01 at 09:32 +0800, Jianguo Wu wrote:
>>>
>>> So if config NUMA, kernel memory will not be linear mapping anymore? For
>>> example,
>>>
>>> Node 0 Node 1
>>>
>>> 0 ~ 10G 11G~14G
It has nothing to do with linear mapping, I think.
>>>
>>> kernel memory only at Node 0? Can part of kernel memory also at Node 1?
Please refer to find_zone_movable_pfns_for_nodes().
The kernel is not only on node0. It uses all the online nodes evenly. :)
>>>
>>> How big is kernel direct mapping memory in x86_64? Is there max limit?
>>
>>
>> Max kernel direct mapping memory in x86_64 is 64TB.
>
> For example, I have 8G memory, all of them will be direct mapping for
> kernel? then userspace memory allocated from where?
I think you misunderstood what Wu tried to say. :)
The kernel mapped that large space, it doesn't mean it is using that
large space.
The mapping is to make kernel be able to access all the memory, not for
the kernel
to use only. User space can also use the memory, but each process has
its own mapping.
For example:
64TB, what ever
xxxTB, what ever
logic address space: |_____kernel_______|_________user_________________|
\ \ / /
\ /\ /
physical address space: |___\/__\/_____________| 4GB or
8GB, what ever
*****
The ***** part physical is mapped to user space in the process' own
pagetable.
It is also direct mapped in kernel's pagetable. So the kernel can also
access it. :)
>
>>
>>> It seems that only around 896MB on x86_32.
>>>
>>>>
>>>> We need firmware take part in, such as SRAT in ACPI BIOS, or the firmware
>>>> based memory migration mentioned by Liu Jiang.
>>>
>>> Is there any material about firmware based memory migration?
No, I don't have any because this is a functionality of machine from HUAWEI.
I think you can ask Liu Jiang or Wu Jianguo to share some with you. :)
Thanks. :)
next prev parent reply other threads:[~2013-02-01 1:57 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 9:32 [PATCH v6 00/15] memory-hotplug: hot-remove physical memory Tang Chen
2013-01-09 9:32 ` [PATCH v6 01/15] memory-hotplug: try to offline the memory twice to avoid dependence Tang Chen
2013-01-09 9:32 ` [PATCH v6 02/15] memory-hotplug: check whether all memory blocks are offlined or not when removing m Tang Chen
2013-01-09 23:11 ` [PATCH v6 02/15] memory-hotplug: check whether all memory blocks are offlined or not when removi Andrew Morton
2013-01-10 5:56 ` Tang Chen
2013-01-09 9:32 ` [PATCH v6 03/15] memory-hotplug: remove redundant codes Tang Chen
2013-01-09 9:32 ` [PATCH v6 04/15] memory-hotplug: remove /sys/firmware/memmap/X sysfs Tang Chen
2013-01-09 22:49 ` Andrew Morton
2013-01-10 6:07 ` Tang Chen
2013-01-09 23:19 ` Andrew Morton
2013-01-10 6:15 ` Tang Chen
2013-01-09 9:32 ` [PATCH v6 05/15] memory-hotplug: introduce new function arch_remove_memory() for removing page table Tang Chen
2013-01-09 22:50 ` [PATCH v6 05/15] memory-hotplug: introduce new function arch_remove_memory() for removing page t Andrew Morton
2013-01-10 2:25 ` Tang Chen
2013-01-09 9:32 ` [PATCH v6 06/15] memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap Tang Chen
2013-01-09 9:32 ` [PATCH v6 07/15] memory-hotplug: move pgdat_resize_lock into sparse_remove_one_section() Tang Chen
2013-01-09 9:32 ` [PATCH v6 08/15] memory-hotplug: Common APIs to support page tables hot-remove Tang Chen
2013-01-29 13:02 ` Simon Jeons
2013-01-30 1:53 ` Jianguo Wu
2013-01-30 2:13 ` Simon Jeons
2013-01-29 13:04 ` Simon Jeons
2013-01-30 2:16 ` Tang Chen
2013-01-30 3:27 ` Simon Jeons
2013-01-30 5:55 ` Tang Chen
2013-01-30 7:32 ` Simon Jeons
2013-02-04 23:04 ` Andrew Morton
2013-01-09 9:32 ` [PATCH v6 09/15] memory-hotplug: remove page table of x86_64 architecture Tang Chen
2013-01-09 9:32 ` [PATCH v6 10/15] memory-hotplug: remove memmap of sparse-vmemmap Tang Chen
2013-01-09 9:32 ` [PATCH v6 11/15] memory-hotplug: Integrated __remove_section() of CONFIG_SPARSEMEM_VMEMMAP Tang Chen
2013-01-09 9:32 ` [PATCH v6 12/15] memory-hotplug: memory_hotplug: clear zone when removing the memory Tang Chen
2013-01-09 9:32 ` [PATCH v6 13/15] memory-hotplug: remove sysfs file of node Tang Chen
2013-01-09 9:32 ` [PATCH v6 14/15] memory-hotplug: free node_data when a node is offlined Tang Chen
2013-01-09 9:32 ` [PATCH v6 15/15] memory-hotplug: Do not allocate pdgat if it was not freed when offline Tang Chen
2013-01-09 22:23 ` [PATCH v6 00/15] memory-hotplug: hot-remove physical memory Andrew Morton
2013-01-10 2:17 ` Tang Chen
2013-01-10 7:14 ` Glauber Costa
2013-01-10 7:31 ` Kamezawa Hiroyuki
2013-01-10 7:55 ` Glauber Costa
2013-01-10 8:23 ` Kamezawa Hiroyuki
2013-01-10 8:36 ` Glauber Costa
2013-01-10 8:39 ` Kamezawa Hiroyuki
2013-01-09 23:33 ` Andrew Morton
2013-01-10 2:18 ` Tang Chen
2013-01-29 12:52 ` Simon Jeons
2013-01-30 2:32 ` Tang Chen
2013-01-30 2:48 ` Simon Jeons
2013-01-30 3:00 ` Tang Chen
2013-01-30 10:15 ` Tang Chen
2013-01-30 10:18 ` Tang Chen
2013-01-31 1:22 ` Simon Jeons
2013-01-31 3:31 ` Tang Chen
2013-01-31 6:19 ` Simon Jeons
2013-01-31 7:10 ` Tang Chen
2013-01-31 8:17 ` Simon Jeons
2013-01-31 8:48 ` Simon Jeons
2013-01-31 9:44 ` Tang Chen
2013-01-31 10:38 ` Simon Jeons
2013-02-01 1:32 ` Jianguo Wu
2013-02-01 1:36 ` Simon Jeons
2013-02-01 1:57 ` Jianguo Wu
2013-02-01 2:06 ` Simon Jeons
2013-02-01 2:18 ` Jianguo Wu
2013-02-01 1:57 ` Tang Chen [this message]
2013-02-01 2:17 ` Simon Jeons
2013-02-01 2:42 ` Tang Chen
2013-02-01 3:06 ` Simon Jeons
2013-02-01 3:39 ` Tang Chen
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