NAME    [Toc]    [Back]

       unix_master  -  General:  Forces execution onto the master
       CPU

SYNOPSIS    [Toc]    [Back]

       void unix_master(
               void );

ARGUMENTS    [Toc]    [Back]

       None

DESCRIPTION    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

       routines: unix_release(9r)



                                                  unix_master(9r)