.MP Output Field Descriptions

Output from .MP appears in one of is of the following forms:

ffdf500c InUse: pVP=ff1df060 RefCnt=0001 Flg=0 ll=00 sl=00 Blk=00000 Frame=00001

ffdfcdac Idle:  pVP=ff1e6ba8 Blink=01261 Flg=0 Flink=0127a Blk=0004b Frame=01279

ffdf50b4 Free:               BLink=001f1 Flg=4 FLink=0000d Blk=00001 Frame=0000f

Each of the fields has the following meaning:

address

The linear address of the PF structure is given to the left of each display line.
type
The type of PF is displayed in the second column. Three types are possible: Free Idle and InUse.
pVP=
The linear address of the associated Virtual Page Structure. See .MV Command for information on displaying Virtual Page Structures.
RefCnt
The number of PTEs that reference the frame of physical storage represented by this PF. A reference count greater than 1 indicates shared memory, some instances of which will be represented by VMCOs (see .MC command).

When a PTE is attached to an existing PF then the Refcnt is incremented.

When a page of memory is freed, the Refcnt is decremented. If it becomes zero the PF may be eligible for putting on the Idle list.

PFs corresponding to UVIRT storage are zeroed unless aliased by non-UVIRT storage. In either case no reference accounting is performed for UVIRT mappings.

Blink=
The backward or right link to the previous Idle or Free PF.
Flink=
The forward or left link to the next Idle or Free PF.
Flg=
PF flags.

The following flags are defined:

┌────────────┬──────────┬──────────────────────────────┐
│name        │bit mask  │description                   │
├────────────┼──────────┼──────────────────────────────┤
│PF_FAST     │0x1       │frame is fast memory          │
├────────────┼──────────┼──────────────────────────────┤
│PF_BUSY     │0x2       │frame is busy                 │
├────────────┼──────────┼──────────────────────────────┤
│PF_FREE     │0x4       │frame is free                 │
├────────────┼──────────┼──────────────────────────────┤
│PF_RES      │0x8       │reserved                      │
└────────────┴──────────┴──────────────────────────────┘

Notes: PF_FAST flag is set for some physical storage frames below 640K.

PF_BUSY signifies that access to the PF is being serialised by the page frame manager. This is normally followed by setting the VP_BUSY flag in the associated VP, if reset or setting the VP_WANTED flag and waiting on the the Block Id of the VP address. Under the debug kernel the thread slot of the VP semaphore owner is saved in vp_semowner (VP+0x0a) See .PB command for information on thread slots waiting on Block Ids.

ll=
Count of number of long-term lock requests active against this page frame. This is incremented when a request to lock a range of pages of a memory object is made. It is also, but rarely, set to 1 to isolate page frames that have caused trap 2 errors from which the system has recovered. See also .MO command output for flags relating to memory object locking.
sl=
Count of number of short-term lock requests active against this page frame. This is incremented when a request to lock a range of pages of a memory object is made. For related information, see .MO command output for flags relating to memory object locking.
Blk=
Specifies the swap disk frame, loader block number or diagnostic flag depending on the flag settings of the corresponding Virtual Page Structure pointed to by the pVP= field.

When VP_DF is set and VP_DISCARDABLE is reset then Blk= is the swap disk frame number that contains a copy of the page frame.

When VP_DISCARDABLE is set and VP_RESIDENT is reset then the Blk= field is the Loader block Id. Except for a special case noted below, this is a page index, starting from 1, into the objects of the module as an aggregated whole, with the size of each object rounded up to a page boundary. The special case occurs when the memory object that owes this page frame has an hmte set to system object id 0xffc0, Discard Owner. When this occurs the following special block numbers may be used:

0x0fffe

System Infoseg
0x0fffd
Local Infoseg
0x0fffc
invalid LDT pages
When VP_DF and VP_DISCARDABLE are reset the Blk= usually indicates the last cross-linked swapper disk frame (unless its zero), however under the debug kernel negative values are used to indicate errors or instances where swapper frames have been freed because the corresponding PTE for the frame was found to be dirty. The following error indicators are possible:
• When also Flg=9 then the physical frame caused a Trap 2 error, but the system was able to recover the data. The frame is isolated from further use by setting ll=1, refcnt=1 and PF_FREE flags are reset and pVP=pgVPBasePg -3
  A page-in operation failed with ERROR_SWAP_IO_PROBLEMS
  -4
  A page_out operation failed with PGPO_FAILED
  -5
  A page_out operation failed with ERROR_SWAP_FILE_FULL
  Otherwise disk frame reclamation is indicated by Blk= values of: -1, -2, -7, -9 and 0xfff0.

  For related VP information, see .MV command.

Frame=
This is the physical page frame number that this Page Frame Structure represents.

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