{
assert(reader_data);
sig_done = 0;
- smp_mb(); /* write sig_done before sending the signals */
+ /*
+ * pthread_kill has a smp_mb(). But beware, we assume it performs
+ * a cache flush on architectures with non-coherent cache. Let's play
+ * safe and don't assume anything : we use smp_mc() to make sure the
+ * cache flush is enforced.
+ * smp_mb(); write sig_done before sending the signals
+ */
+ smp_mc(); /* write sig_done before sending the signals */
pthread_kill(tid, SIGURCU);
/*
* Wait for sighandler (and thus mb()) to execute on every thread.
* BUSY-LOOP.
*/
- while (sig_done < 1)
- smp_rmb(); /* ensure we re-read sig-done */
+ while (LOAD_SHARED(sig_done) < 1)
+ cpu_relax();
smp_mb(); /* read sig_done before ending the barrier */
}
if (!reader_data)
return;
sig_done = 0;
- smp_mb(); /* write sig_done before sending the signals */
+ /*
+ * pthread_kill has a smp_mb(). But beware, we assume it performs
+ * a cache flush on architectures with non-coherent cache. Let's play
+ * safe and don't assume anything : we use smp_mc() to make sure the
+ * cache flush is enforced.
+ * smp_mb(); write sig_done before sending the signals
+ */
+ smp_mc(); /* write sig_done before sending the signals */
for (index = reader_data; index < reader_data + num_readers; index++)
pthread_kill(index->tid, SIGURCU);
/*
* Wait for sighandler (and thus mb()) to execute on every thread.
* BUSY-LOOP.
*/
- while (sig_done < num_readers)
- smp_rmb(); /* ensure we re-read sig-done */
+ while (LOAD_SHARED(sig_done) < num_readers)
+ cpu_relax();
smp_mb(); /* read sig_done before ending the barrier */
}
#endif
if (wait_loops++ == KICK_READER_LOOPS) {
force_mb_single_thread(index->tid);
wait_loops = 0;
+ } else {
+ cpu_relax();
}
}
}
* waiting forever while new readers are always accessing data (no
* progress).
*/
- smp_mb();
+ smp_mc();
/*
* Wait for previous parity to be empty of readers.
* the writer waiting forever while new readers are always accessing
* data (no progress).
*/
- smp_mb();
+ smp_mc();
switch_next_urcu_qparity(); /* 1 -> 0 */
* waiting forever while new readers are always accessing data (no
* progress).
*/
- smp_mb();
+ smp_mc();
/*
* Wait for previous parity to be empty of readers.