STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE);
/*
- * Must commit qparity update to memory before waiting for other parity
- * quiescent state. Failure to do so could result in the writer waiting
- * forever while new readers are always accessing data (no progress).
- * Ensured by STORE_SHARED and LOAD_SHARED.
+ * Must commit rcu_gp_ctr update to memory before waiting for quiescent
+ * state. Failure to do so could result in the writer waiting forever
+ * while new readers are always accessing data (no progress). Enforce
+ * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr.
*/
+ barrier();
/*
+ *
* Adding a smp_mb() which is _not_ formally required, but makes the
* model easier to understand. It does not have a big performance impact
* anyway, given this is the write-side.
}
list_for_each_entry_safe(index, tmp, ®istry, head) {
- if (!rcu_old_gp_ongoing(&index->ctr))
+ if (!rcu_gp_ongoing(&index->ctr))
list_move(&index->head, &qsreaders);
}
/*
* Must finish waiting for quiescent state for parity 0 before
- * committing qparity update to memory. Failure to do so could result in
- * the writer waiting forever while new readers are always accessing
- * data (no progress).
- * Ensured by STORE_SHARED and LOAD_SHARED.
+ * committing next rcu_gp_ctr update to memory. Failure to do so could
+ * result in the writer waiting forever while new readers are always
+ * accessing data (no progress). Enforce compiler-order of load
+ * rcu_reader ctr before store to rcu_gp_ctr.
*/
+ barrier();
/*
* Adding a smp_mb() which is _not_ formally required, but makes the
{
rcu_reader.tid = pthread_self();
assert(rcu_reader.need_mb == 0);
- assert(rcu_reader.ctr == 0);
+ assert(!(rcu_reader.ctr & RCU_GP_CTR_NEST_MASK));
mutex_lock(&rcu_gp_lock);
rcu_init(); /* In case gcc does not support constructor attribute */