Bug 1796043

Summary: Documentation change regarding vmstat manpage
Product: Red Hat Enterprise Linux 7 Reporter: Rohan <rgaikwad>
Component: procps-ngAssignee: Jan Rybar <jrybar>
Status: CLOSED ERRATA QA Contact: Karel Volný <kvolny>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 7.6CC: kvolny, rhel-docs
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Linux   
Whiteboard:
Fixed In Version: procps-ng-3.3.10-28.el7 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 1829920 (view as bug list) Environment:
Last Closed: 2020-09-29 20:36:50 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1829920    

Description Rohan 2020-01-29 13:31:52 UTC 
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.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Comment 9 errata-xmlrpc 2020-09-29 20:36:50 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (procps-ng bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:4017