.MV Output Field Descriptions

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

VPI=0000 pVP=ff1df000 Res Frame=0000 Flg=410 HobPg=0000 Hob=ff77 Ref=001 Own=000
VPI=0001 pVP=ff1df00c Res Block=0000 Flg=c00 HobPg=0000 Hob=ff6c Ref=042 Own=000

VPI=0d40 pVP=ff1e8f00 free FLink=ff1e9fec BLink=ff1e8cf0

Each of the fields has the following meaning:

VPI=

The VP index into the array of VPs.
pVP=
The linear address of the VP.
status
The status of the VP interpreted from the Flg field. The following values may appear:

SOW

Swap on Write flag (VP_SOW set)
Res
Page is resident (VP_RESIDENT set)
Dsc
Page is discardable (VP_DISCARDABLE set)
Swp
Page is swappable (VP_DISCARDABLE reset)
free
VP is free (vp_refcount=0)
Block=nnnn
The cross-linked loader block number or swapper disk frame. This implies the virtual page is not attached to a PF. If it is:

discardable

then it is linked to a loader block id,
swappable
then it is linked to a swapper disk frame.
When the page is swappable (VP_DISCARDABLE reset) and does not have a disk frame (VP_DF reset) then the following special Block values may be used:
• Allocate PF on demand 1
  Allocate on demand zero-fill page
  2
  page is in a broken disk frame
  Frame=nnn
  The virtual page is linked to PF nnnn Refer to the .MP command for displaying information about the related page frame.
  Flink=
  Forward link of a free VP. This is only of relevance to the VP at the head of a bundle of free VPs. See Free Virtual Page Structures for information on how free VPs are linked.
  Blink=
  Backward link of a free VP. This is only of relevance to the VP at the head and tail of a bundle of free VPs. See Free Virtual Page Structures for information on how free VPs are linked.
  Flg=
  VP flags.

  The following flags are defined:

  ┌────────────────┬──────────┬──────────────────────────────┐│name            │bit mask  │description                   │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_BUSY         │0x001     │page semaphore taken          │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_WANTED       │0x002     │page semaphore requested      │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_CACHE        │0x004     │search page cache for pf      │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_PFIDLE       │0x008     │cross linked to idle pf       │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_PF           │0x010     │cross linked to pf            │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_DF           │0x020     │has swap file disk frame      │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_DIRTY        │0x040     │contents written to - from pte│
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_SHDIRTY      │0x080     │shadow dirty bit (for VDMs)   │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_SOW          │0x100     │change to swappable on write  │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_PRIVATIZED   │0x200     │vp privatized                 │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_RESIDENT     │0x400     │cannot be moved - value from  │
  │                │          │pte                           │
  ├────────────────┼──────────┼──────────────────────────────┤
  │VP_DISCARDABLE  │0x800     │1 = discardable, 0 = swappable│
  └────────────────┴──────────┴──────────────────────────────┘
  

  Notes:

  PF_BUSY signifies that access to the VP is being serialised by the page frame manager.

  VP_WANTED signifies that a thread is waiting to mark the VP busy. The thread will wait on a 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 Own= field of the .MV display. See .PB command for information on thread slots waiting on Block Ids.

  HobPg=
  The relative page number of the memory object that this VP is assigned to. See Hob= field below.
  Hob=
  The hob of the memory object to which this page is assigned.

  Note: Use

           .MOC hob
  

  to obtain the virtual address and owner information relating to this VP. See .MO command for more information.

  Ref=
  The number of memory objects sharing this page of data. A reference count greater than 1 indicates shared memory, some instances of which will be represented by VMCOs (see .MC command) and others by aliases (see .ML command).

  The reference count is incremented and decremented according to usage. When the count becomes zero the VP is no longer in use and any committed physical storage or swapper storage my become eligible for freeing.

  UVIRT storage is not represented by VPs thus reference accounting is not performed.

  Own=
  The thread slot number of the current owner of the VP semaphore. This field is only used in the debug kernel and will only have significance if the VP_BUSY or WP_WANTED flags are set. See .PB command for information on thread slots waiting on Block Ids.

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