git: kernel - SWAP CACHE part 12/many - Add swapcache cleanup state

Matthew Dillon dillon at
Sat Feb 6 10:13:45 PST 2010

commit 00a3fdca11527a9e70b79270e03d979267907ca4
Author: Matthew Dillon <dillon at>
Date:   Sat Feb 6 08:57:05 2010 -0800

    kernel - SWAP CACHE part 12/many - Add swapcache cleanup state
    * Add a small state machine and hysteresis to flip between swapcache
      writing and swapcache cleaning.  The swapcache is written to until
      (unless) it hits 75% use.  If this occurs it switches to cleaning
      mode to get rid of swapcache pages until it gets down to 70%.  While
      in cleaning mode burst accumulation still occurs.  Then it flips back.
      Currently the cleaning mode tries to choose swap meta-blocks which
      are wholely swapped (have no VM pages), running linearly through
      the VM object list in order to try to clean contiguous areas of
      the swapcache.  The idea is to reduce fragmentation that would lead
      to excessive disk seeking.  At the same time the limited cleaning
      run (only 5% of the swap cache) should prevent any large-scale
      excessive deletion of the swapcache.
    * Add a new VM object type, OBJT_MARKER, which may be used by iterators
      running through the vm_object_list.

Summary of changes:
 .../linux/i386/linprocfs/linprocfs_misc.c          |    5 +-
 sys/emulation/linux/linux_misc.c                   |    5 +-
 sys/vm/swap_pager.c                                |   75 +++++
 sys/vm/swap_pager.h                                |    2 +
 sys/vm/vm_meter.c                                  |    7 +-
 sys/vm/vm_object.c                                 |    4 +
 sys/vm/vm_object.h                                 |    3 +-
 sys/vm/vm_swapcache.c                              |  321 +++++++++++++-------
 8 files changed, 307 insertions(+), 115 deletions(-)

DragonFly BSD source repository

More information about the Commits mailing list