linux-kernel - Re: [8/8,v3] NUMA Hotplug Emulator: documentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 21 Nov 2010 23:03:45 +0800
From:	Américo Wang <xiyou.wangcong@...il.com>
To:	shaohui.zheng@...el.com
Cc:	akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, haicheng.li@...ux.intel.com,
	lethal@...ux-sh.org, ak@...ux.intel.com,
	shaohui.zheng@...ux.intel.com, Haicheng Li <haicheng.li@...el.com>
Subject: Re: [8/8,v3] NUMA Hotplug Emulator: documentation

On Wed, Nov 17, 2010 at 10:08:07AM +0800, shaohui.zheng@...el.com wrote:
>+2) CPU hotplug emulation:
>+
>+The emulator reserve CPUs throu grub parameter, the reserved CPUs can be
>+hot-add/hot-remove in software method, it emulates the process of physical
>+cpu hotplug.
>+
>+When hotplug a CPU with emulator, we are using a logical CPU to emulate the CPU
>+socket hotplug process. For the CPU supported SMT, some logical CPUs are in the
>+same socket, but it may located in different NUMA node after we have emulator.
>+We put the logical CPU into a fake CPU socket, and assign it an unique
>+phys_proc_id. For the fake socket, we put one logical CPU in only.
>+
>+ - to hide CPUs
>+	- Using boot option "maxcpus=N" hide CPUs
>+	  N is the number of initialize CPUs
>+	- Using boot option "cpu_hpe=on" to enable cpu hotplug emulation
>+      when cpu_hpe is enabled, the rest CPUs will not be initialized
>+
>+ - to hot-add CPU to node
>+	$ echo nid > cpu/probe
>+
>+ - to hot-remove CPU
>+	$ echo nid > cpu/release
>+

Again, we already have software CPU hotplug,
i.e. /sys/devices/system/cpu/cpuX/online.

You need to pick up another name for this.

>From your documentation above, it looks like you are trying
to move one CPU between nodes?

>+	cpu_hpe=on/off
>+		Enable/disable cpu hotplug emulation with software method. when cpu_hpe=on,
>+		sysfs provides probe/release interface to hot add/remove cpu dynamically.
>+		this option is disabled in default.
>+			

Why not just a CONFIG? IOW, why do we need to make another boot
parameter for this?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/