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unix_master(9r)
NAME
  unix_master - General: Forces execution onto the master CPU

SYNOPSIS
  void unix_master(
	  void );

ARGUMENTS
  None

DESCRIPTION
  The unix_master routine forces execution of the kernel thread onto the
  master CPU (also called the boot CPU). In other words, unix_master binds
  the kernel thread to the master CPU. To release the kernel thread from the
  bind to the master CPU, call the unix_release routine. You can make
  recursive calls to unix_master as long as you make an equal number of calls
  to unix_release.

  The unix_master routine provides another way besides the simple and complex
  lock routines to make a kernel module symmetric multiprocessing (SMP) safe.
  Although calling unix_master is not optimal for performance on an SMP CPU,
  it does provide third-party kernel module writers with an easy way to make
  their modules SMP safe without using the lock routines.

NOTES
  Device drivers should not directly call the unix_master and unix_release
  routines. One exception to this recommendation is when you want a device
  driver's kernel threads to run only on the master CPU. This situation
  occurs when your driver creates and starts its own kernel threads and you
  set the d_funnel member of the associated dsent structure to the value
  DEV_FUNNEL. In this case, each kernel thread must call unix_master once to
  ensure that the kernel thread runs only on the master CPU. Remember to make
  a corresponding call to unix_release.

CAUTIONS
  To avoid deadlock, do not call the unix_master routine under the following
  circumstances:

    ·  When holding a simple lock

    ·  In the driver's interrupt service routine

RETURN VALUES
  None

SEE ALSO
  routines: unix_release(9r)

Index for Section 9r

Alphabetical listing for U

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