On Thu, Dec 09, 2010 at 01:29:28PM -0800, David Rientjes wrote: > On Thu, 9 Dec 2010, Shaohui Zheng wrote: > > > > I don't think you should be using memparse() to support this type of > > > interface, the standard way of writing memory locations is by writing > > > address in hex as the first example does. The idea is to not try to make > > > things simpler by introducing multiple ways of doing the same thing but > > > rather to standardize on a single interface. > > > > Undoubtedly, A hex is the best way to represent a physical address. If we use > > memparse function, we can use the much simpler way to represent an address, > > it is not the offical way, but it takes many conveniences if we just want to > > to some simple test. > > > > Testing code should be removed from the patch prior to proposal. > > > When we reserce memory, we use mempasre to parse the mem=XXX parameter, we can > > avoid the complicated translation when we add memory thru the add_memory interface, > > how about still use the memparse here? but remove it from the document since it is > > just for some simple testing. > > > > We really don't want a public interface to have undocumented behavior, so > it would be much better to retain the documentation if you choose to keep > the memparse(). I disagree that converting the mem= parameter to hex is > "complicated," however, so I'd prefer that the interface is similar to > that of add_node. > Okay, I will keep interface to accept hex address which is simliar wiht add_node. > > > > + printk(KERN_INFO "Add a memory section to node: %d.\n", nid); > > > > + phys_addr = memparse(buf, NULL); > > > > + ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT); > > > > > > Does the add_memory() call handle memoryless nodes such that they > > > appropriately transition to N_HIGH_MEMORY when memory is added? > > > > For memoryless nodes, it will cause OOM issue on old kernel version, but now > > memoryless node is already supported, and the test result matches it well. The > > emulator is a tool to reproduce the OOM issue in eraly kernel. > > > > That doesn't address the question. My question is whether or not adding > memory to a memoryless node in this way transitions its state to > N_HIGH_MEMORY in the VM? I guess that you are talking about memory hotplug on x86_32, memory hotplug is NOT supported well for x86_32, and the function add_memory does not consider this situlation. For 64bit, N_HIGH_MEMORY == N_NORMAL_MEMORY, so we need not to do the transition. -- Thanks & Regards, Shaohui -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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@xxxxxxxxx";> email@xxxxxxxxx </a>