git: systat - clarify 'Free' in systat -vm 1

Matthew Dillon dillon at
Wed Aug 30 00:02:47 PDT 2017

commit a4c31683d0550ba3aef4c22e6179952f3251101d
Author: Matthew Dillon <dillon at>
Date:   Tue Aug 29 23:56:42 2017 -0700

    systat - clarify 'Free' in systat -vm 1
    * Clarify Free by indicating i+c+f (inactive + cache + free).  That is,
      the Free memory reported in the upper left counts the Inactive page
      queue as part of its total, even though it isn't quite free.
    * The main reason for this is that when the memory pressure de-stresses,
      the VM system doesn't bother wasting time moving pages out of the inactive
      queue, even though they are effectively freeable.
      On the otherhand, if the system is under significant memory pressure,
      the inactive queue will itself become stressed and minimize.
      This makes it a fairly accurate representation of what is potentially
      freeable (albeit with some effort by the paging system).

Summary of changes:
 usr.bin/systat/vmstat.c | 2 ++
 1 file changed, 2 insertions(+)

DragonFly BSD source repository

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