CHAPTER9:MEMORYMANAGEMENT(内存管理)Background:Logicalvs.PhysicalAddressSpaceBackground:Memory-ManagementUnit(MMU)Background:DynamicrelocationusingarelocationregisterBackground:MultistepProcessingofaUserProgramBackground:BindingofInstructionsandDatatoMemoryBackground:DynamicLoading(v.s.staticloading)Background:DynamicLinking(v.s.staticlinking)Background:Overlays（覆盖）Assumethatthesizesofthesecomponentsareasfollows:Pass170KBPass280KBSymboltable20KBCommonroutines30KBIfonly150KBisavailable,whatshouldwedo?Solution（P205）Background:OverlaysforaTwo-PassAssemblerSWAPPING（交换）Swapping:SchematicViewSwapping:PerformanceCONTIGUOUSMEMORYALLOCATIONContiguousMemoryAllocation:MemoryprotectionContiguousMemoryAllocation:HardwareSupportforRelocationandLimitRegistersContiguousMemoryAllocation(Cont.)DynamicStorage-AllocationProblemContiguousMemoryAllocation:FragmentationPAGING(分页)解决外部碎片PagingPagingPagingPagingPaging:PagesizePaging:PagesizePaging:PagesizePaging:PagesizePaging:Pagesize（页大小）Paging：TheOSConcernPaging：TheOSConcernPaging:ImplementationofPageTablePaging:ImplementationofPageTablePaging:ImplementationofPageTablePaging:ImplementationofPageTablePaging:ImplementationofPageTable:PagingHardwareWithTLBPaging:ImplementationofPageTable:PagingHardwareWithTLBPaging:ImplementationofPageTable:PagingHardwareWithTLBPaging:MemoryProtectionPaging:MemoryProtection:Valid(v)orInvalid(i)BitInAPageTablePaging:PageTableStructurePaging:PageTableStructure:HierarchicalPageTablesPaging:PageTableStructure:HierarchicalPageTablesPaging:PageTableStructure:HierarchicalPageTablesPaging:PageTableStructure:HierarchicalPageTablesPaging:PageTableStructure:HierarchicalPageTablesPaging:PageTableStructure:HashedPageTablesPaging:PageTableStructure:HashedPageTablesPaging:PageTableStructure:InvertedPageTablesPaging:PageTableStructure:InvertedPageTablesPaging:SharedPagesPaging:SharedPagesPaging:SharedPagesSEGMENTATIONSegmentationSegmentation:User’sviewofaprogramSegmentation:User’sViewofaProgramSegmentation