SYSTEM_INFO

typedef struct _SYSTEM_INFO {
  union {
    DWORD  dwOemId;
    struct {
      WORD wProcessorArchitecture;
      WORD wReserved;
    };
  };
  DWORD     dwPageSize;
  LPVOID    lpMinimumApplicationAddress;
  LPVOID    lpMaximumApplicationAddress;
  DWORD_PTR dwActiveProcessorMask;
  DWORD     dwNumberOfProcessors;
  DWORD     dwProcessorType;
  DWORD     dwAllocationGranularity;
  WORD      wProcessorLevel;
  WORD      wProcessorRevision;
} SYSTEM_INFO;

MIN : 65536因為前面64KB is always free

WOW64: 如果32 process在64 bit os跑, 用getsysteminfo會拉到錯的, 要用GetNativeSystemInfo來拉

MEMORSTATUS

typedef struct _MEMORYSTATUS {
  DWORD  dwLength;
  DWORD  dwMemoryLoad;
  SIZE_T dwTotalPhys;
  SIZE_T dwAvailPhys;
  SIZE_T dwTotalPageFile;
  SIZE_T dwAvailPageFile;
  SIZE_T dwTotalVirtual;
  SIZE_T dwAvailVirtual;
} MEMORYSTATUS, *LPMEMORYSTATUS;

length必須要先設

Load: use percent memory

Commit : commit是一個狀態, page被標記成commit後才能被load到實體記憶體上

如果超過4G, 要用Ex版

如何得到某個page上的資訊?

Virtual Query 傳baseAddress的pointer給他, 傳memory_basic_information的structure pointer

typedef struct _MEMORY_BASIC_INFORMATION {
  PVOID  BaseAddress;
  PVOID  AllocationBase;
  DWORD  AllocationProtect;
  SIZE_T RegionSize;
  DWORD  State;
  DWORD  Protect;
  DWORD  Type;
} MEMORY_BASIC_INFORMATION, *PMEMORY_BASIC_INFORMATION;

allocationBase: 是只用virtual alloc所分配出來的base addr base address: 是只要query這段的base addr

Stat: MEM_COMMIT MEM_FREE MEM_RESERVE

• Working set 算的是process所有的resource包含share memory, physical memory
• private bype是這個process真的能用的, 有包含page out的那些

Ch15 Using virtual memory in your own

How to reserving a region?

VirtualAlloc with starting addr, size, type

RESET: flag data in the range is no longer of interest reserve size must allocate 64kb

How to commit a region reserve first and commit. ex want to commit 6kb, reserver region start 2 kb (5242880 is the first address + 2*1024) + 6kb

large page support, GetLargePageMinimum() performance很好!

decommit : virtualFree dwsize = 0, 不得指定region大小讓系統自己處理 freetype= release會先 discommit > free 如果只想discommit, 就不要用release

virtual protect reset: 目的在於減少IO, reset也是整個page不可指定大小, size應為page size

AWE:address windows extension 會永遠在memory上不會到disk 是在額外的空間request, 不會再process address space被看到

AllocateUserPhisicalPage RamPage是由系統決定的, 不應該更改 RAM block are not share.