cvs commit: src/sys/amd64/amd64 pmap.c src/sys/arm/arm pmap.c src/sys/i386/i386 pmap.c src/sys/ia64/ia64 pmap.c src/sys/powerpc/powerpc mmu_if.m mmu_oea.c pmap_dispatch.c src/sys/sparc64/sparc64 pmap.c src/sys/sun4v/sun4v pmap.c ...

[Alan Cox]

alc         2007-11-17 22:52:30 UTC

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      pmap.c 
    sys/arm/arm          pmap.c 
    sys/i386/i386        pmap.c 
    sys/ia64/ia64        pmap.c 
    sys/powerpc/powerpc  mmu_if.m mmu_oea.c pmap_dispatch.c 
    sys/sparc64/sparc64  pmap.c 
    sys/sun4v/sun4v      pmap.c 
    sys/vm               pmap.h vm_object.c 
  Log:
  Prevent the leakage of wired pages in the following circumstances:
  First, a file is mmap(2)ed and then mlock(2)ed.  Later, it is truncated.
  Under "normal" circumstances, i.e., when the file is not mlock(2)ed, the
  pages beyond the EOF are unmapped and freed.  However, when the file is
  mlock(2)ed, the pages beyond the EOF are unmapped but not freed because
  they have a non-zero wire count.  This can be a mistake.  Specifically,
  it is a mistake if the sole reason why the pages are wired is because of
  wired, managed mappings.  Previously, unmapping the pages destroys these
  wired, managed mappings, but does not reduce the pages' wire count.
  Consequently, when the file is unmapped, the pages are not unwired
  because the wired mapping has been destroyed.  Moreover, when the vm
  object is finally destroyed, the pages are leaked because they are still
  wired.  The fix is to reduce the pages' wired count by the number of
  wired, managed mappings destroyed.  To do this, I introduce a new pmap
  function pmap_page_wired_mappings() that returns the number of managed
  mappings to the given physical page that are wired, and I use this
  function in vm_object_page_remove().
  
  Reviewed by: tegge
  MFC after: 6 weeks
  
  Revision  Changes    Path
  1.594     +29 -0     src/sys/amd64/amd64/pmap.c
  1.89      +21 -0     src/sys/arm/arm/pmap.c
  1.599     +31 -0     src/sys/i386/i386/pmap.c
  1.193     +32 -0     src/sys/ia64/ia64/pmap.c
  1.8       +15 -0     src/sys/powerpc/powerpc/mmu_if.m
  1.116     +22 -0     src/sys/powerpc/powerpc/mmu_oea.c
  1.11      +7 -0      src/sys/powerpc/powerpc/pmap_dispatch.c
  1.168     +20 -0     src/sys/sparc64/sparc64/pmap.c
  1.41      +28 -0     src/sys/sun4v/sun4v/pmap.c
  1.81      +1 -0      src/sys/vm/pmap.h
  1.387     +13 -1     src/sys/vm/vm_object.c