Block Management Package Header (VMBH) for OS/2 Warp V4.0 and OS/2 Warp V3.0

The BMP is a generalised facility used to manage tables of fixed length entities. The BMP consists of a header followed by the table it manages. The use of the BMP is many and varied, but almost always occurs where an expandable table of fixed length entries is required by the system.

Pointers

The VMBH prefixes tables, which are pointed to by:
• parVMOne
  The table of VM Arena Records (VMARs).
  _pobVMOne
  The table of VM Object Records (VMOBs).
  _palVMAliases.
  The table of VM Alias Records (VMALs).
  _pcoVMOne
  The table of VM Context Records (VMCO).
  s2BmpSel
  BMP Selector for Device Driver Strategy 2 Request Packets.
  pFSLIST_BMP
  ListIO BMP segment.
  NmpBmpSel
  BMP Selector for Named Pipe NP Structures.
  _pVPB_BMP
  Volume Parameters Block BMP.
  _pFPEMVMBH
  Floating point emulator BMP.
  _pkshdVMDescs
  BMP for Swappable Kernel Heap Descriptors (VMKSHD).
  pslhLockHandles
  BMP for Memory Lock Handles.
  _pbhPvwRPD
  PerfView counters
  _paPTDA
  The array of PTDA structures.
  _paTCB
  The array of TCB structures.
  Locations
  Many.
  VM Owner
  The VMBH is usualy part of the the object from which the BMP is allocted, thus adopts the object id of the table.

  Format

  VMBH BMP Header Structure.

  ┌────────────────┬──────┬──────┬────┬────────────────────────────────────────┐│Field Name      │Offset│Length│Type│Description                             │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_pbFreeHead   │+0    │4     │D   │Free list pointer                       │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_pbEndBlocks  │+4    │4     │D   │End of valid blocks                     │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_pbEndVirt    │+8    │4     │D   │End of virtual memory                   │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_pbLastBusy   │+C    │4     │D   │Pointer to last busy block              │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_pfnisbusy    │+10   │4     │D   │Busy block identifier function          │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_filler       │+14   │4     │D   │Paragraph boundary filler               │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_flpgtype     │+18   │4     │D   │New page type flags                     │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_cbPerBlock   │+1c   │2     │W   │Size of a block in bytes                │
  ├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
  │bh_hob          │+1e   │2     │W   │Object record handle                    │
  └────────────────┴──────┴──────┴────┴────────────────────────────────────────┘
  

  bh_flpgtype flag definitions.

  ┌──────────────┬──────────┬─────────────────────────────────┐
  │Name          │Bit Mask  │Description                      │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_CONTIG     │0x00000001│contiguous physical memory       │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_NOINCR     │0x00000001│don't increment physical addrs   │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_W          │0x00000002│Writable - value from pte        │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_U          │0x00000004│user mode accessible - from pte  │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_X          │0x00000008│eXecutable                       │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_R          │0x00000010│Readable                         │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_1M         │0x00000020│must reside below 1 meg physical │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_GUARD      │0x00000040│guard page - from pte            │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_16M        │0x00000040│must reside below 16 meg physical│
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_ZEROFILL   │0x00000080│zero initialize pages            │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_SWAPONWRITE│0x00000100│value from vp                    │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_UVIRT      │0x00000200│value from pte                   │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_RESIDENT   │0x00000400│value from pte                   │
  ├──────────────┼──────────┼─────────────────────────────────┤
  │PG_DISCARDABLE│0x00000800│value from vp                    │
  └──────────────┴──────────┴─────────────────────────────────┘
  

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