Unit OS5: Windows Memory Management

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10Protecting <strong>Memory</strong>AttributePAGE_NOACCESSPAGE_READONLYPAGE_READWRITEPAGE_EXECUTEPAGE_EXECUTE_READPAGE_EXECUTE_READWRITEPAGE_WRITECOPYPAGE_EXECUTE_WRITECOPYPAGE_GUARDDescriptionRead/write/execute causes access violationWrite/execute causes access violation; read permittedRead/write accesses permittedAny read/write causes access violation; execution of code ispermitted (relies on special processor support)Read/execute access permitted (relies on special processorsupport)All accesses permitted (relies on special processor support)Write access causes the system to give process a private copyof this page; attempts to execute code cause access violationWrite access causes creation of private copy of page.Any read/write attempt raises EXCEPTION_GUARD_PAGEand turns off guard page status
11Reserving & Committing <strong>Memory</strong>Optional 2-phase approach to memory allocation:1. Reserve address space (in multiples of page size)2. Commit storage in that address spaceCan be combined in one call (VirtualAlloc, VirtualAllocEx)Reserved memory:Range of virtual addresses reserved for future use (contiguous buffer)Accessing reserved memory results in access violationFast, inexpensiveCommitted memory:Has backing store (pagefile.sys, memory-mapped file)Either private or mapped into a view of a sectionDecommit via VirtualFree, VirtualFreeExA thread‘s user-mode stack is constructed usingthis 2-phase approach: initial reserved size is 1MB,only 2 pages are committed: stack & guard page
Page 1 and 2: Windows Memory Management (I)Memory
Page 3 and 4: 3IntroductionMain Tasks:Translating
Page 5 and 6: 5Main ComponentsSystem services for
Page 7 and 8: 7Large PagesArchitecture Small Page
Page 9: 9Large PagesDisadvantage of large p
Page 13 and 14: 13Shared MemoryLike most modern OS
Page 15 and 16: 15Viewing DLLs & Memory MappedFiles
Page 17 and 18: 17Controlling DEPBCD nx values:OptI
Page 19 and 20: 19DEP on 32-bit WindowsHardware DEP
Page 21 and 22: 21Copy-On-Write PagesUsed for shari
Page 23 and 24: 23How Copy-On-Write WorksAfterOrig.
Page 25 and 26: 25Virtual Address Space (V.A.S.)Pro
Page 27 and 28: 27Windows User ProcessAddress Space
Page 29 and 30: 29Large Address Space AwareImagesIm
Page 31 and 32: 31Address Windowing Extensions32-bi
Page 33 and 34: 33Working Set ManagementDefault wor
Page 35 and 36: 35Look-Aside ListsAnother fast memo
Page 37 and 38: Heap Manager StructureTwo layers:Co
Page 39 and 40: Physical Memory Limits32-Bit 64-Bit
Page 41 and 42: 41Cache SupportSystem wide cache me
Page 43 and 44: 43Windows API MemoryManagement Arch
Page 45 and 46: 45Source Code ReferencesWindows Res
Page 47: ContentView DLLs using “listdll.e

Unit OS5: Windows Memory Management

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