From: Shaohui Zheng <shaohui.zheng@intel.com> To: Dave Hansen <dave@linux.vnet.ibm.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, haicheng.li@linux.intel.com, lethal@linux-sh.org, ak@linux.intel.com, shaohui.zheng@linux.intel.com, Haicheng Li <haicheng.li@intel.com>, Wu Fengguang <fengguang.wu@intel.com>, Greg KH <greg@kroah.com> Subject: Re: [7/8,v3] NUMA Hotplug Emulator: extend memory probe interface to support NUMA Date: Thu, 18 Nov 2010 12:36:41 +0800 [thread overview] Message-ID: <20101118043641.GB2408@shaohui> (raw) In-Reply-To: <1290019807.9173.3789.camel@nimitz> On Wed, Nov 17, 2010 at 10:50:07AM -0800, Dave Hansen wrote: > On Wed, 2010-11-17 at 10:08 +0800, shaohui.zheng@intel.com wrote: > > And more we make it friendly, it is possible to add memory to do > > > > echo 3g > memory/probe > > echo 1024m,3 > memory/probe > > > > It maintains backwards compatibility. > > > > Another format suggested by Dave Hansen: > > > > echo physical_address=0x40000000 numa_node=3 > memory/probe > > > > it is more explicit to show meaning of the parameters. > > The other thing that Greg suggested was to use configfs. Looking back > on it, that makes a lot of sense. We can do better than these "probe" > files. > > In your case, it might be useful to tell the kernel to be able to add > memory in a node and add the node all in one go. That'll probably be > closer to what the hardware will do, and will exercise different code > paths that the separate "add node", "then add memory" steps that you're > using here. > > For the emulator, I also have to wonder if using debugfs is the right > was since its ABI is a bit more, well, _flexible_ over time. :) First, the emulator is just for test purpose, and I believe that only very few people will use it, so we did not want to take so many modification. the more you changed, the more bugs you may get. the memory/probe interface is already enough to test memory hot-add. Second, if we want to use configfs and debugfs for cpu/memory probe interface, it should implemented in another series patch since it is not part of the emulator. We have 8 patches in this patchset now, it is should be very long patch if want to add all in. > > > + depends on NUMA_HOTPLUG_EMU > > + ---help--- > > + Enable memory hotplug emulation. Reserve memory with grub parameter > > + "mem=N"(such as mem=1024M), where N is the initial memory size, the > > + rest physical memory will be removed from e820 table; the memory probe > > + interface is for memory hot-add to specified node in software method. > > + This is for debuging and testing purpose > > mem= actually sets the largest physical address that we're trying to > use. If you have a 256MB hole at 768MB, then mem=1G will only get you > 768MB of memory. We probably get this wrong in a number of other places > in the documentation, but we might as well get it right here. > > Maybe something like: > > Enable emulation of hotplug of NUMA nodes. To use this, you > must also boot with the kernel command-line parameter > "mem=N"(such as mem=1024M), where N is the highest physical > address you would like to use at boot. The rest of physical > memory will be removed from firmware tables and may be then be > hotplugged with this feature. This is for debuging and testing > purposes. > > Note that you can still examine the original, non-modified > firmware tables in: /sys/firmware/memmap > > -- Dave I did not aware the memory hole here, good catching. -- Thanks & Regards, Shaohui
WARNING: multiple messages have this Message-ID (diff)
From: Shaohui Zheng <shaohui.zheng@intel.com> To: Dave Hansen <dave@linux.vnet.ibm.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, haicheng.li@linux.intel.com, lethal@linux-sh.org, ak@linux.intel.com, shaohui.zheng@linux.intel.com, Haicheng Li <haicheng.li@intel.com>, Wu Fengguang <fengguang.wu@intel.com>, Greg KH <greg@kroah.com> Subject: Re: [7/8,v3] NUMA Hotplug Emulator: extend memory probe interface to support NUMA Date: Thu, 18 Nov 2010 12:36:41 +0800 [thread overview] Message-ID: <20101118043641.GB2408@shaohui> (raw) In-Reply-To: <1290019807.9173.3789.camel@nimitz> On Wed, Nov 17, 2010 at 10:50:07AM -0800, Dave Hansen wrote: > On Wed, 2010-11-17 at 10:08 +0800, shaohui.zheng@intel.com wrote: > > And more we make it friendly, it is possible to add memory to do > > > > echo 3g > memory/probe > > echo 1024m,3 > memory/probe > > > > It maintains backwards compatibility. > > > > Another format suggested by Dave Hansen: > > > > echo physical_address=0x40000000 numa_node=3 > memory/probe > > > > it is more explicit to show meaning of the parameters. > > The other thing that Greg suggested was to use configfs. Looking back > on it, that makes a lot of sense. We can do better than these "probe" > files. > > In your case, it might be useful to tell the kernel to be able to add > memory in a node and add the node all in one go. That'll probably be > closer to what the hardware will do, and will exercise different code > paths that the separate "add node", "then add memory" steps that you're > using here. > > For the emulator, I also have to wonder if using debugfs is the right > was since its ABI is a bit more, well, _flexible_ over time. :) First, the emulator is just for test purpose, and I believe that only very few people will use it, so we did not want to take so many modification. the more you changed, the more bugs you may get. the memory/probe interface is already enough to test memory hot-add. Second, if we want to use configfs and debugfs for cpu/memory probe interface, it should implemented in another series patch since it is not part of the emulator. We have 8 patches in this patchset now, it is should be very long patch if want to add all in. > > > + depends on NUMA_HOTPLUG_EMU > > + ---help--- > > + Enable memory hotplug emulation. Reserve memory with grub parameter > > + "mem=N"(such as mem=1024M), where N is the initial memory size, the > > + rest physical memory will be removed from e820 table; the memory probe > > + interface is for memory hot-add to specified node in software method. > > + This is for debuging and testing purpose > > mem= actually sets the largest physical address that we're trying to > use. If you have a 256MB hole at 768MB, then mem=1G will only get you > 768MB of memory. We probably get this wrong in a number of other places > in the documentation, but we might as well get it right here. > > Maybe something like: > > Enable emulation of hotplug of NUMA nodes. To use this, you > must also boot with the kernel command-line parameter > "mem=N"(such as mem=1024M), where N is the highest physical > address you would like to use at boot. The rest of physical > memory will be removed from firmware tables and may be then be > hotplugged with this feature. This is for debuging and testing > purposes. > > Note that you can still examine the original, non-modified > firmware tables in: /sys/firmware/memmap > > -- Dave I did not aware the memory hole here, good catching. -- Thanks & Regards, Shaohui -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-11-18 5:57 UTC|newest] Thread overview: 139+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-11-17 2:07 [0/8,v3] NUMA Hotplug Emulator - Introduction & Feedbacks shaohui.zheng 2010-11-17 2:07 ` shaohui.zheng 2010-11-17 2:08 ` [1/8,v3] NUMA Hotplug Emulator: add function to hide memory region via e820 table shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 8:16 ` David Rientjes 2010-11-17 8:16 ` David Rientjes 2010-11-18 9:20 ` Shaohui Zheng 2010-11-18 9:20 ` Shaohui Zheng 2010-11-18 21:16 ` David Rientjes 2010-11-18 21:16 ` David Rientjes 2010-11-19 0:12 ` Shaohui Zheng 2010-11-19 0:12 ` Shaohui Zheng 2010-11-21 0:45 ` David Rientjes 2010-11-21 0:45 ` David Rientjes 2010-11-21 14:00 ` Américo Wang 2010-11-21 14:00 ` Américo Wang 2010-11-21 21:33 ` David Rientjes 2010-11-21 21:33 ` David Rientjes 2010-11-17 2:08 ` [2/8,v3] NUMA Hotplug Emulator: infrastructure of NUMA hotplug emulation shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 8:16 ` David Rientjes 2010-11-17 8:16 ` David Rientjes 2010-11-17 7:51 ` Shaohui Zheng 2010-11-17 7:51 ` Shaohui Zheng 2010-11-17 21:10 ` David Rientjes 2010-11-17 21:10 ` David Rientjes 2010-11-18 4:14 ` Shaohui Zheng 2010-11-18 4:14 ` Shaohui Zheng 2010-11-18 6:27 ` Paul Mundt 2010-11-18 6:27 ` Paul Mundt 2010-11-18 5:27 ` Shaohui Zheng 2010-11-18 5:27 ` Shaohui Zheng 2010-11-18 21:24 ` David Rientjes 2010-11-18 21:24 ` David Rientjes 2010-11-19 0:32 ` Shaohui Zheng 2010-11-19 0:32 ` Shaohui Zheng 2010-11-21 0:48 ` David Rientjes 2010-11-21 0:48 ` David Rientjes 2010-11-21 2:28 ` [patch 1/2] x86: add numa=possible command line option David Rientjes 2010-11-21 2:28 ` David Rientjes 2010-11-21 2:28 ` [patch 2/2] mm: add node hotplug emulation David Rientjes 2010-11-21 2:28 ` David Rientjes 2010-11-21 17:34 ` Greg KH 2010-11-21 17:34 ` Greg KH 2010-11-21 21:48 ` David Rientjes 2010-11-21 21:48 ` David Rientjes 2010-11-21 23:08 ` [patch 2/2 v2] " David Rientjes 2010-11-21 23:08 ` David Rientjes 2010-11-22 0:56 ` Greg KH 2010-11-22 0:56 ` Greg KH 2010-11-28 1:52 ` David Rientjes 2010-11-28 1:52 ` David Rientjes 2010-11-28 5:17 ` Greg KH 2010-11-28 5:17 ` Greg KH 2010-11-30 0:04 ` David Rientjes 2010-11-30 0:04 ` David Rientjes 2010-11-21 14:26 ` [patch 1/2] x86: add numa=possible command line option Américo Wang 2010-11-21 14:26 ` Américo Wang 2010-11-21 21:46 ` David Rientjes 2010-11-21 21:46 ` David Rientjes 2010-11-22 15:43 ` Américo Wang 2010-11-22 15:43 ` Américo Wang 2010-11-21 15:14 ` [2/8,v3] NUMA Hotplug Emulator: infrastructure of NUMA hotplug emulation Li, Haicheng 2010-11-21 15:14 ` Li, Haicheng 2010-11-21 21:42 ` David Rientjes 2010-11-21 21:42 ` David Rientjes 2010-11-18 21:19 ` David Rientjes 2010-11-18 21:19 ` David Rientjes 2010-11-17 2:08 ` [3/8,v3] NUMA Hotplug Emulator: Userland interface to hotplug-add fake offlined nodes shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 8:16 ` David Rientjes 2010-11-17 8:16 ` David Rientjes 2010-11-17 2:08 ` [4/8,v3] NUMA Hotplug Emulator: Abstract cpu register functions shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 2:08 ` [5/8,v3] NUMA Hotplug Emulator: support cpu probe/release in x86 shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-21 14:45 ` Américo Wang 2010-11-21 14:45 ` Américo Wang 2010-11-22 0:01 ` Shaohui Zheng 2010-11-22 0:01 ` Shaohui Zheng 2010-11-22 15:51 ` Américo Wang 2010-11-22 15:51 ` Américo Wang 2010-11-22 23:29 ` Shaohui Zheng 2010-11-22 23:29 ` Shaohui Zheng 2010-11-17 2:08 ` [6/8,v3] NUMA Hotplug Emulator: Fake CPU socket with logical CPU on x86 shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 2:08 ` [7/8,v3] NUMA Hotplug Emulator: extend memory probe interface to support NUMA shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 18:50 ` Dave Hansen 2010-11-17 18:50 ` Dave Hansen 2010-11-17 21:18 ` David Rientjes 2010-11-17 21:18 ` David Rientjes 2010-11-17 21:55 ` Dave Hansen 2010-11-17 21:55 ` Dave Hansen 2010-11-17 22:44 ` David Rientjes 2010-11-17 22:44 ` David Rientjes 2010-11-17 23:00 ` Dave Hansen 2010-11-17 23:00 ` Dave Hansen 2010-11-17 23:17 ` David Rientjes 2010-11-17 23:17 ` David Rientjes 2010-11-18 16:59 ` Aaron Durbin 2010-11-18 16:59 ` Aaron Durbin 2010-11-18 4:48 ` Shaohui Zheng 2010-11-18 4:48 ` Shaohui Zheng 2010-11-18 6:24 ` Paul Mundt 2010-11-18 6:24 ` Paul Mundt 2010-11-18 21:28 ` David Rientjes 2010-11-18 21:28 ` David Rientjes 2010-11-18 21:31 ` David Rientjes 2010-11-18 21:31 ` David Rientjes 2010-11-18 4:36 ` Shaohui Zheng [this message] 2010-11-18 4:36 ` Shaohui Zheng 2010-11-19 7:51 ` Shaohui Zheng 2010-11-19 16:36 ` Dave Hansen 2010-11-19 16:36 ` Dave Hansen 2010-11-17 2:08 ` [8/8,v3] NUMA Hotplug Emulator: documentation shaohui.zheng 2010-11-17 2:08 ` shaohui.zheng 2010-11-17 23:06 ` Randy Dunlap 2010-11-17 23:06 ` Randy Dunlap 2010-11-18 2:31 ` Shaohui Zheng 2010-11-18 2:31 ` Shaohui Zheng 2010-11-21 15:03 ` Américo Wang 2010-11-21 15:03 ` Américo Wang 2010-11-21 15:16 ` Li, Haicheng 2010-11-21 15:16 ` Li, Haicheng 2010-11-21 23:33 ` Shaohui Zheng 2010-11-21 23:33 ` Shaohui Zheng 2010-11-22 16:04 ` Américo Wang 2010-11-22 16:04 ` Américo Wang 2010-11-22 23:23 ` Shaohui Zheng 2010-11-22 23:23 ` Shaohui Zheng 2010-11-17 5:22 ` [0/8,v3] NUMA Hotplug Emulator - Introduction & Feedbacks Paul Mundt 2010-11-17 5:22 ` Paul Mundt 2010-11-19 5:54 ` Shaohui Zheng 2010-11-19 5:54 ` Shaohui Zheng 2010-11-17 9:26 ` Yinghai Lu 2010-11-17 9:26 ` Yinghai Lu 2010-11-18 2:03 ` Shaohui Zheng 2010-11-18 2:03 ` Shaohui Zheng
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