Description of problem:

Vmstat command result shows only blocked process which are waiting for IO to get completed and not all process in 'D/UN' state however the man page of vmstat has incorrect information. 

It is written as,

 b: The number of processes in uninterruptible sleep.

But as per the actual result, it should be written as, 

  b: The number of processes blocked on IO (in uninterruptible sleep.)


Actual Result :

FIELD DESCRIPTION FOR VM MODE
   Procs
       r: The number of runnable processes (running or waiting for run time).
       b: The number of processes in uninterruptible sleep.

Expected Result :

FIELD DESCRIPTION FOR VM MODE
   Procs
       r: The number of runnable processes (running or waiting for run time).
       b: The number of processes blocked on IO (in uninterruptible sleep.)
                                  ^^^^^^^^^^^^^

Additional info:
  
FYI :

Below is the last update from bugzilla=1374332 hence opening this new documentation BZ 

~~~~~~~~~~~~~~~Snippet from Bugzilla ID=1374332~~~~~~~~~~~~~~~~~~~~
I took a peek at the source for vmstat and it's interesting that in the
absence of a /proc/stat "procs_blocked" field (Linux 2.5.46
(approximately) and below), it will iterate through all /proc/<PID>/stat
files looking for 'R' or 'D' fields.  In 2002 code was added to use
/proc/stat "procs_blocked" if it was available.  Nothing in the commit
message for this change makes reference to this field or any change in
reporting semantics.  IMHO, this was a bug introduced into vmstat long
ago... since nobody has complained in the interim, I would suggest
changing the vmstat documentation to match its current implementation:

FIELD DESCRIPTION FOR VM MODE
   Procs
       r: The number of runnable processes (running or waiting for run time).
       b: The number of processes blocked on IO (in uninterruptible sleep.)
                                  ^^^^^^^^^^^^^
or something to the effect of explaining that the value is only the
subset of TASK_UNINTERRUPTIBLE waiting on I/O completion.

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