curlwp_bind(9) - NetBSD Manual Pages

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


NAME

     curlwp_bind, curlwp_bindx -- temporarily bind the current thread to the
     running CPU


SYNOPSIS

     #include <sys/lwp.h>

     int
     curlwp_bind(void);

     void
     curlwp_bindx(int bound);


DESCRIPTION

     curlwp_bind() temporarily binds the current thread to the running CPU and
     returns a cookie bound which must be passed to curlwp_bindx() when done.

     During this time, the thread may sleep and may be preempted, but it will
     never migrate to another CPU until curlwp_bindx().  If the CPU is
     offlined, the thread will not run again until the CPU is onlined again.

     Calls to curlwp_bind() and curlwp_bindx() may be nested as long as the
     matching cookie is passed.


EXAMPLES

     For temporary access to resources protected by psref(9) from an arbitrary
     thread:

           struct psref psref;
           int bound, s;

           bound = curlwp_bind();
           s = pserialize_read_enter();
           IFADDR_READER_FOREACH(ifa, ifp) {
                   ifa_acquire(ifa, &psref);
                   pserialize_read_exit(s);

                   /*
                    * ifa is now stable, even if caller is preempted
                    * or sleeps
                    */

                   s = pserialize_read_enter();
                   ifa_release(ifa, &psref);
           }
           pserialize_read_exit(s);
           curlwp_bindx(bound);


CODE REFERENCES

     sys/sys/lwp.h


SEE ALSO

     localcount(9), pserialize(9), psref(9), spl(9)


HISTORY

     The curlwp_bind function first appeared in NetBSD 8.0 to support
     psref(9).

NetBSD 11.99                   December 31, 2025                  NetBSD 11.99