IRC, freenode, #hurd, 2012-07-04

<braunr> yes, we have integer overflows on resident_page_count, but
  luckily, the member is rarely used

See also gnumach vm object resident page count.

IRC, freenode, #hurd, 2013-06-04

<elmig> this is declared as int on vm_object.h
<elmig> and as it as counter it's always positive
<braunr> yes it should be unsigned
<elmig> ok
<braunr> but leave it as it is for consistency with the rest
<elmig> i send patch :)
<braunr> please no
<braunr> unless you've fully determined the side effects
<elmig> i've grepped the vars and saw only comparisons > and = 0
<elmig> never less than 0
<braunr> > 0 is the same
<braunr> well
<braunr> > not, but >= would be a problem
<elmig> http://paste.debian.net/plain/8527
<elmig> asctually no >=0
<braunr> still, i don't want to change that unless it's strictly necessary
<braunr> hum, you're grepping ref_count, not resident_page_count
<elmig> i did both
<elmig> on resident_page_count theres resident_page_count >= 0
<elmig> = 0, == 0
<braunr> this isn't the only possible issue
<braunr> anyway
<braunr> for now there is no reason to change anything unless you do a full
  review
<elmig> only place i see resdent_page_count and page_count being decreased
  it's on vm/vm_resident.c
<elmig> vm_page_remove() and vm_page_replace()