cvs commit: src/sys/alpha/alpha interrupt.c src/sys/alpha/include param.h src/sys/amd64/amd64 intr_machdep.c src/sys/amd64/include param.h src/sys/conf NOTES options src/sys/i386/i386 intr_machdep.c src/sys/i386/include param.h src/sys/ia64/ia64 ...

[John Baldwin]

jhb         2004-07-02 20:21:44 UTC

  FreeBSD src repository

  Modified files:
    sys/alpha/alpha      interrupt.c 
    sys/alpha/include    param.h 
    sys/amd64/amd64      intr_machdep.c 
    sys/amd64/include    param.h 
    sys/conf             NOTES options 
    sys/i386/i386        intr_machdep.c 
    sys/i386/include     param.h 
    sys/ia64/ia64        interrupt.c 
    sys/kern             kern_intr.c kern_mutex.c kern_shutdown.c 
                         kern_switch.c kern_synch.c sched_4bsd.c 
                         sched_ule.c 
    sys/powerpc/powerpc  intr_machdep.c 
    sys/sparc64/sparc64  intr_machdep.c 
    sys/sys              interrupt.h proc.h 
    sys/vm               vm_zeroidle.c 
  Log:
  Implement preemption of kernel threads natively in the scheduler rather
  than as one-off hacks in various other parts of the kernel:
  - Add a function maybe_preempt() that is called from sched_add() to
    determine if a thread about to be added to a run queue should be
    preempted to directly.  If it is not safe to preempt or if the new
    thread does not have a high enough priority, then the function returns
    false and sched_add() adds the thread to the run queue.  If the thread
    should be preempted to but the current thread is in a nested critical
    section, then the flag TDF_OWEPREEMPT is set and the thread is added
    to the run queue.  Otherwise, mi_switch() is called immediately and the
    thread is never added to the run queue since it is switch to directly.
    When exiting an outermost critical section, if TDF_OWEPREEMPT is set,
    then clear it and call mi_switch() to perform the deferred preemption.
  - Remove explicit preemption from ithread_schedule() as calling
    setrunqueue() now does all the correct work.  This also removes the
    do_switch argument from ithread_schedule().
  - Do not use the manual preemption code in mtx_unlock if the architecture
    supports native preemption.
  - Don't call mi_switch() in a loop during shutdown to give ithreads a
    chance to run if the architecture supports native preemption since
    the ithreads will just preempt DELAY().
  - Don't call mi_switch() from the page zeroing idle thread for
    architectures that support native preemption as it is unnecessary.
  - Native preemption is enabled on the same archs that supported ithread
    preemption, namely alpha, i386, and amd64.
  
  This change should largely be a NOP for the default case as committed
  except that we will do fewer context switches in a few cases and will
  avoid the run queues completely when preempting.
  
  Approved by:    scottl (with his re@ hat)
  
  Revision  Changes    Path
  1.79      +1 -1      src/sys/alpha/alpha/interrupt.c
  1.34      +2 -0      src/sys/alpha/include/param.h
  1.7       +1 -1      src/sys/amd64/amd64/intr_machdep.c
  1.12      +2 -0      src/sys/amd64/include/param.h
  1.1240    +6 -0      src/sys/conf/NOTES
  1.459     +1 -0      src/sys/conf/options
  1.7       +1 -1      src/sys/i386/i386/intr_machdep.c
  1.71      +2 -0      src/sys/i386/include/param.h
  1.46      +1 -1      src/sys/ia64/ia64/interrupt.c
  1.111     +3 -16     src/sys/kern/kern_intr.c
  1.140     +6 -0      src/sys/kern/kern_mutex.c
  1.153     +24 -13    src/sys/kern/kern_shutdown.c
  1.68      +93 -4     src/sys/kern/kern_switch.c
  1.252     +4 -1      src/sys/kern/kern_synch.c
  1.43      +11 -1     src/sys/kern/sched_4bsd.c
  1.110     +10 -1     src/sys/kern/sched_ule.c
  1.6       +1 -1      src/sys/powerpc/powerpc/intr_machdep.c
  1.19      +0 -4      src/sys/sparc64/sparc64/intr_machdep.c
  1.28      +1 -1      src/sys/sys/interrupt.h
  1.384     +2 -0      src/sys/sys/proc.h
  1.26      +2 -0      src/sys/vm/vm_zeroidle.c