splraiseipl(9) - NetBSD Manual Pages

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SPLRAISEIPL(9)         NetBSD Kernel Developer's Manual         SPLRAISEIPL(9)


NAME

     splraiseipl -- raise the system priority level


SYNOPSIS

     #include <sys/param.h>

     int
     splraiseipl(ipl_cookie_t icookie);


DESCRIPTION

     splraiseipl() raises the system priority level to the level specified by
     icookie.  icookie should be a value returned by makeiplcookie().

     In general, device drivers should not make use of this interface.  To
     ensure correct synchronization, device drivers should use the condvar(9),
     mutex(9), and rwlock(9) interfaces.

     See the spl(9) manual page for a description of interrupt priority lev-
     els.


RETURN VALUES

     splraiseipl() returns saved priority level which can be used for splx().


EXAMPLES

     The following two lines are functional equivalents.

             s = splraiseipl(makeiplcookie(IPL_VM));

             s = splvm();

     Because makeiplcookie() can be slow and is not expected to be used in a
     perfomance critical path, it's better to do it beforehand.

             initialization_code(ipl_t ipl)
             {

                     ourcookie = makeiplcookie(ipl);
             }

             performance_critical_code()
             {
                     int s;

                     s = splraiseipl(ourcookie);
                     do_something();
                     splx(s);
             }


SEE ALSO

     condvar(9), makeiplcookie(9), mutex(9), rwlock(9), spl(9)

NetBSD 5.2                     February 11, 2007                    NetBSD 5.2