Thank you for your comment. I'm very glad. :-) > Yasunori Goto <y-goto@xxxxxxxxxxxxxx> wrote: > > > > I'll post newest patches for memory hotadd with pgdat allocation as V3. > > There are many changes to make more common code. > > General comments: > > - Thanks for working against -mm. It can be a bit of a pain, but it > eases staging and integration later on. > > - Please review all the code to check that all those functions which can > be made static are indeed made static. I see quite a few global > functions there. > - Make sure that all functions which can be tagged __meminit are so tagged. > > - It would be useful to build a CONFIG_MEMORY_HOTPLUG=n kernel both with > and without the patchsets and to publish and maintain the increase in > code size. Ideally that increase will be zero. Probably it won't be, > and it'd be nice to understand why, and to minimise it. Ok. I'll check and fix it. > > - Arch issues: > > - Which architectures is this patchset aimed at and tested on? IA64. At least, Fujitsu is making this style hot-add feature on ia64 box which is named as PrimeQuest. (SGI or HP might wait it.) > - Which other architectures might be able to use this code in the > future? Because we should ask the maintainers of those other > architectures to take a look at the changes. I heard from Andi-san that x86-64 will need this. And ppc64 might use some of my patch. It depends on .... - There is Numa box on its architecture. - One node of NUMA will be hot-added. > - What locking does node hot-add use? There are quite a few places in > the kernel which cheerfully iterate across node lists while assuming that > they won't change. The usage of stop_machine_run() is supposed to cover > all that, I assume? If my understanding is correct, there is 2 critical point. - One is zonelist update, indeed. Stop_machine_run() can cover it. - Another is node_online_map and NODE_DATA(). If node_online_map is onlined before that NODE_DATA() is updated, or before that pgdat is initialized, kernel might touch uninitialized pgdat. So, node_set_online() is called at final point. The old kernel had pgdat->next link list, it was also critial point for hot-add. But current -mm remove it. So, it is not issue now. :-) Thanks. -- Yasunori Goto - : send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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