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From: John Birrell <jb@FreeBSD.ORG>
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	Tue, 29 Sep 1998 23:36:56 -0700 (PDT)
Date: Tue, 29 Sep 1998 23:36:56 -0700 (PDT)
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Subject: cvs commit: src/lib/libc_r/uthread uthread_gc.c Makefile.inc
         uthread_init.c uthread_find_thread.c uthread_kern.c
         uthread_create.c uthread_exit.c
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jb          1998/09/29 23:36:56 PDT

  Modified files:
    lib/libc_r/uthread   Makefile.inc uthread_init.c 
                         uthread_find_thread.c uthread_kern.c 
                         uthread_create.c uthread_exit.c 
  Added files:
    lib/libc_r/uthread   uthread_gc.c 
  Log:
  Move the cleanup code that frees memory allocated for a dead thread from
  the thread kernel into a garbage collector thread which is started when
  the fisrt thread is created (other than the initial thread). This
  removes the window of opportunity where a context switch will cause a
  thread that has locked the malloc spinlock, to enter the thread kernel,
  find there is a dead thread and try to free memory, therefore trying
  to lock the malloc spinlock against itself.
  
  The garbage collector thread acts just like any other thread, so
  instead of having a spinlock to control accesses to the dead thread
  list, it uses a mutex and a condition variable so that it can happily
  wait to be signalled when a thread exists.
  
  Revision  Changes    Path
  1.16      +2 -1      src/lib/libc_r/uthread/Makefile.inc
  1.9       +5 -0      src/lib/libc_r/uthread/uthread_init.c
  1.2       +10 -5     src/lib/libc_r/uthread/uthread_find_thread.c
  1.13      +2 -80     src/lib/libc_r/uthread/uthread_kern.c
  1.10      +16 -0     src/lib/libc_r/uthread/uthread_create.c
  1.6       +17 -44    src/lib/libc_r/uthread/uthread_exit.c