On 03/10/20 at 11:10am, Michal Hocko wrote: > On Sun 08-03-20 09:35:11, Baoquan He wrote: > > In commit f70029bbaacbfa8f0 ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), > > the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY, so the > > conditional check in paging_init() doesn't make any sense any more. > > Remove it. > > Please expand more. I would really have to refresh the intention of the > code but from a quick look at the code CONFIG_HIGHMEM still makes > N_MEMORY != N_NORMAL_MEMORY. So what what does this change mean for that > config? Thanks for looking into this. I was trying to explain that CONFIG_MOVABLE_NODE made N_MEMORY have chance to take different enum value. Do you think the below saying is OK to you? ~~~ In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make any sense any more. Let's remove it. ~~~ Thanks Baoquan