Blocking_and_Suspended back to Blocking?

gistfile1.txt

Suppose victim is in BLOCKING and suspend count is 2.

Old technique

  BLOCKING|susp=2
    abort_blocking() -> returns AbortBlockingWait
  BLOCKING_AND_SUSPENDED|susp=2
    waits on resume semaphore
    ... (suspend initiator calls resume)
  BLOCKING_AND_SUSPENDED|susp=1
    ... (suspend initiator has nothing else to do)
    // vicitim still waiting
    ... (suspend initiator calls resume again)
  RUNNING
    ... (suspend initiator signals on resume semaphore)
    // victim wakes up

New technique

  BLOCKING|susp=2
    abort_blocking() -> returns AbortBlockingWaitAndRetry
  BLOCKING_AND_SUSPENDED|susp=2
    waits on resume semaphore
    ... (suspend initiator calls resume)
  BLOCKING|susp=1
    ... (suspend initiator has nothing else to do)
    // victim still waiting
    ... (suspend initiator calls resume again)
  BLOCKING|susp=0
    ... (suspend initiator posts on the semaphore)
    //victim wakes up
    goto top
    abort_blocking () -> AbortBlockingOk
  RUNNING


Suppose victim is in BLOCKING and suspend count is 1.

Old technique

  BLOCKING|susp=1
    abort_blocking() -> return AbortBlockingWait
  BLOCKING_AND_SUSPENDED|susp=1
    waits on resume semaphore
    ... (suspend initiator calls resume)
  RUNNING
    // victim wakes up

New technique

  BLOCKING|susp=1
    abort_blocking() -> return AbortBlockingWaitAndRetry
  BLOCKING_AND_SUSPENDED|susp=1
    wait on resume semaphore
    ... (suspend initiator calls resume)
  BLOCKING|susp=0
    ... (suspend initiator posts on the semaphore)
    // victim wakes up
    goto top
    abort_blocking () -> AbortBlockingOk
  RUNNING