On Wed, 17 Apr 2013, Yasuaki Ishimatsu wrote: > > Why not simply do what generic sparsemem support does by testing > > PageSlab(virt_to_head_page(res)) and calling kfree() if true and freeing > > back to bootmem if false? This should be like a five line patch. > > Is your explanation about free_section_usemap()? > If so, I don't think we can release resource structure like > free_section_usemap(). Right, you can't release it like free_section_usemap(), but you're free to test for PageSlab(virt_to_head_page(res)) in kernel/resource.c. > In your explanation case, memmap can be released by put_page_bootmem() in > free_map_bootmem() since all pages of memmap is used only for memmap. > But if my understanding is correct, a page of released resource structure > contain other purpose objects allocated by bootmem. So we cannot > release resource structure like free_section_usemap(). > I'm thinking it would be much easier to just suppress the kfree() if !PageSlab. If you can free an entire page with free_bootmem_late(), that would be great, but I'm thinking that will take more work than it's worth. It seems fine to just do free_bootmem() and leave those pages as reserved. How much memory are we talking about? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>