1. 19 Nov, 2009 9 commits
    • David Howells's avatar
      FS-Cache: Allow the current state of all objects to be dumped · 4fbf4291
      David Howells authored
      
      
      Allow the current state of all fscache objects to be dumped by doing:
      
      	cat /proc/fs/fscache/objects
      
      By default, all objects and all fields will be shown.  This can be restricted
      by adding a suitable key to one of the caller's keyrings (such as the session
      keyring):
      
      	keyctl add user fscache:objlist "<restrictions>" @s
      
      The <restrictions> are:
      
      	K	Show hexdump of object key (don't show if not given)
      	A	Show hexdump of object aux data (don't show if not given)
      
      And paired restrictions:
      
      	C	Show objects that have a cookie
      	c	Show objects that don't have a cookie
      	B	Show objects that are busy
      	b	Show objects that aren't busy
      	W	Show objects that have pending writes
      	w	Show objects that don't have pending writes
      	R	Show objects that have outstanding reads
      	r	Show objects that don't have outstanding reads
      	S	Show objects that have slow work queued
      	s	Show objects that don't have slow work queued
      
      If neither side of a restriction pair is given, then both are implied.  For
      example:
      
      	keyctl add user fscache:objlist KB @s
      
      shows objects that are busy, and lists their object keys, but does not dump
      their auxiliary data.  It also implies "CcWwRrSs", but as 'B' is given, 'b' is
      not implied.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      4fbf4291
    • David Howells's avatar
      FS-Cache: Annotate slow-work runqueue proc lines for FS-Cache work items · 440f0aff
      David Howells authored
      
      
      Annotate slow-work runqueue proc lines for FS-Cache work items.  Objects
      include the object ID and the state.  Operations include the object ID, the
      operation ID and the operation type and state.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      440f0aff
    • David Howells's avatar
      SLOW_WORK: Allow a requeueable work item to sleep till the thread is needed · 3bde31a4
      David Howells authored
      
      
      Add a function to allow a requeueable work item to sleep till the thread
      processing it is needed by the slow-work facility to perform other work.
      
      Sometimes a work item can't progress immediately, but must wait for the
      completion of another work item that's currently being processed by another
      slow-work thread.
      
      In some circumstances, the waiting item could instead - theoretically - put
      itself back on the queue and yield its thread back to the slow-work facility,
      thus waiting till it gets processing time again before attempting to progress.
      This would allow other work items processing time on that thread.
      
      However, this only works if there is something on the queue for it to queue
      behind - otherwise it will just get a thread again immediately, and will end
      up cycling between the queue and the thread, eating up valuable CPU time.
      
      So, slow_work_sleep_till_thread_needed() is provided such that an item can put
      itself on a wait queue that will wake it up when the event it is actually
      interested in occurs, then call this function in lieu of calling schedule().
      
      This function will then sleep until either the item's event occurs or another
      work item appears on the queue.  If another work item is queued, but the
      item's event hasn't occurred, then the work item should requeue itself and
      yield the thread back to the slow-work facility by returning.
      
      This can be used by CacheFiles for an object that is being created on one
      thread to wait for an object being deleted on another thread where there is
      nothing on the queue for the creation to go and wait behind.  As soon as an
      item appears on the queue that could be given thread time instead, CacheFiles
      can stick the creating object back on the queue and return to the slow-work
      facility - assuming the object deletion didn't also complete.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      3bde31a4
    • David Howells's avatar
      SLOW_WORK: Allow the owner of a work item to determine if it is queued or not · 31ba99d3
      David Howells authored
      
      
      Add a function (slow_work_is_queued()) to permit the owner of a work item to
      determine if the item is queued or not.
      
      The work item is counted as being queued if it is actually on the queue, not
      just if it is pending.  If it is executing and pending, then it is not on the
      queue, but will rather be put back on the queue when execution finishes.
      
      This permits a caller to quickly work out if it may be able to put another,
      dependent work item on the queue behind it, or whether it will have to wait
      till that is finished.
      
      This can be used by CacheFiles to work out whether the creation a new object
      can be immediately deferred when it has to wait for an old object to be
      deleted, or whether a wait must take place.  If a wait is necessary, then the
      slow-work thread can otherwise get blocked, preventing the deletion from
      taking place.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      31ba99d3
    • David Howells's avatar
      SLOW_WORK: Allow the work items to be viewed through a /proc file · 8fba10a4
      David Howells authored
      
      
      Allow the executing and queued work items to be viewed through a /proc file
      for debugging purposes.  The contents look something like the following:
      
          THR PID   ITEM ADDR        FL MARK  DESC
          === ===== ================ == ===== ==========
            0  3005 ffff880023f52348  a 952ms FSC: OBJ17d3: LOOK
            1  3006 ffff880024e33668  2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2
            2  3165 ffff8800296dd180  a 424ms FSC: OBJ17e4: LOOK
            3  4089 ffff8800262c8d78  a 212ms FSC: OBJ17ea: CRTN
            4  4090 ffff88002792bed8  2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2
            5  4092 ffff88002a0ef308  2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2
            6  4094 ffff88002abaf4b8  2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2
            7  4095 ffff88002bb188e0  a 388ms FSC: OBJ17e9: CRTN
          vsq     - ffff880023d99668  1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2
          vsq     - ffff8800295d1740  1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2
          vsq     - ffff880025ba3308  1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2
          vsq     - ffff880024ec83e0  1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2
          vsq     - ffff880026618e00  1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2
          vsq     - ffff880025a2a4b8  1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2
          vsq     - ffff880023cbe6d8  9 212ms FSC: OBJ17eb: LOOK
          vsq     - ffff880024d37590  9 212ms FSC: OBJ17ec: LOOK
          vsq     - ffff880027746cb0  9 212ms FSC: OBJ17ed: LOOK
          vsq     - ffff880024d37ae8  9 212ms FSC: OBJ17ee: LOOK
          vsq     - ffff880024d37cb0  9 212ms FSC: OBJ17ef: LOOK
          vsq     - ffff880025036550  9 212ms FSC: OBJ17f0: LOOK
          vsq     - ffff8800250368e0  9 212ms FSC: OBJ17f1: LOOK
          vsq     - ffff880025036aa8  9 212ms FSC: OBJ17f2: LOOK
      
      In the 'THR' column, executing items show the thread they're occupying and
      queued threads indicate which queue they're on.  'PID' shows the process ID of
      a slow-work thread that's executing something.  'FL' shows the work item flags.
      'MARK' indicates how long since an item was queued or began executing.  Lastly,
      the 'DESC' column permits the owner of an item to give some information.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      8fba10a4
    • Jens Axboe's avatar
      SLOW_WORK: Add delayed_slow_work support · 6b8268b1
      Jens Axboe authored
      
      
      This adds support for starting slow work with a delay, similar
      to the functionality we have for workqueues.
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      6b8268b1
    • Jens Axboe's avatar
      SLOW_WORK: Add support for cancellation of slow work · 01609502
      Jens Axboe authored
      
      
      Add support for cancellation of queued slow work and delayed slow work items.
      The cancellation functions will wait for items that are pending or undergoing
      execution to be discarded by the slow work facility.
      
      Attempting to enqueue work that is in the process of being cancelled will
      result in ECANCELED.
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      01609502
    • Jens Axboe's avatar
      SLOW_WORK: Make slow_work_ops ->get_ref/->put_ref optional · 4d8bb2cb
      Jens Axboe authored
      
      
      Make the ability for the slow-work facility to take references on a work item
      optional as not everyone requires this.
      
      Even the internal slow-work stubs them out, so those can be got rid of too.
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      4d8bb2cb
    • David Howells's avatar
      SLOW_WORK: Wait for outstanding work items belonging to a module to clear · 3d7a641e
      David Howells authored
      
      
      Wait for outstanding slow work items belonging to a module to clear when
      unregistering that module as a user of the facility.  This prevents the put_ref
      code of a work item from being taken away before it returns.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      3d7a641e
  2. 18 Nov, 2009 21 commits
  3. 17 Nov, 2009 10 commits