cvs commit: src/sys/kern subr_witness.c

[Attilio Rao]

attilio     2008-05-07 21:41:36 UTC

  FreeBSD src repository

  Modified files:
    sys/kern             subr_witness.c 
  Log:
  Add a new witness sysctl which returns the relations between any lock
  and its children in the form:
  "parent","child"
  so that head and bottom of an oriented graph can be easilly detected and
  various form of diagrams can be build.
  The sysctl is called debug.witness.graphs and it is read-only; in order
  to get the list of relations, a simple:
  #sysctl debug.witness.graphs
  will do the trick.
  
  This approach has been choosen in order to support easilly things like
  the DOT format and such.  Soon, an auto-explicative awk script, which
  filters simple informations returned by the sysctl and converts them into
  a real DOT script, will be committed to the repository between examples.
  
  Discussed with: rwatson
  
  Revision  Changes    Path
  1.248     +58 -0     src/sys/kern/subr_witness.c