The help option in mm/Kconfig says: > help > SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise > pfn_to_page and page_to_pfn operations. This is the most > efficient option when sufficient kernel resources are available. This doesn't really tell me what it does, what the plusses and minuses are, or when I would or wouldn't need to select it. I don't have enough information to make this config selection (what are "sufficient kernel resources"? Would a 256 meg qemu image qualify?), and the help isn't helping. Looking at the commit, the comment is: > SPARSEMEM_VMEMMAP needs to be a selectable config option to support > building the kernel both with and without sparsemem vmemmap support. This > selection is desirable for platforms which could be configured one way for > platform specific builds and the other for multi-platform builds. Once again, how does someone configuring a system make a decision? Apparently you know, but this documentation isn't saying what the decision criteria or requirements/benefits are. Help? Rob -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
