Messages in this thread |  | | Date | Thu, 17 Jan 2013 14:05:09 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH v3 1/2] memory-hotplug: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_bootmem_info_node() when platform not support |
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On Thu 17-01-13 18:37:10, Lin Feng wrote: [...] > > I am still not sure I understand the relation to MEMORY_HOTREMOVE. > > Is register_page_bootmem_info_node required/helpful even if > > !CONFIG_MEMORY_HOTREMOVE? > From old kenrel's view register_page_bootmem_info_node() is defined in > CONFIG_MEMORY_HOTPLUG_SPARSE, it registers some info for > memory hotplug/remove. If we don't use MEMORY_HOTPLUG feature, this > function is empty, we don't need the info at all. > So this info is not required/helpful if !CONFIG_MEMORY_HOTREMOVE.
OK, then I suggest moving it under CONFIG_MEMORY_HOTREMOVE guards rather than CONFIG_MEMORY_HOTPLUG.
> > Also, now that I am thinking about that more, maybe it would > > be cleaner to put the select into arch/x86/Kconfig and do it > > same as ARCH_ENABLE_MEMORY_{HOTPLUG,HOTREMOVE} (and name it > > ARCH_HAVE_BOOTMEM_INFO_NODE). > > > Maybe put it in mm/Kconfig is a better choice, because if one day > someone implements the register_page_bootmem_info_node() for other > archs they will get some clues here, that's it has been implemented on > x86_64. > But I'm not so sure...
My understanding is that doing that in arch code is more appropriate because it makes the generic code less complicated. But I do not have any strong opinion on that. Looking at other ARCH_ENABLE_MEMORY_HOTPLUG and others suggests that we should be consistent with that.
Thanks! -- Michal Hocko SUSE Labs
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