1 files changed, 25 insertions, 2 deletions
diff --git a/src/core/lib/support/mpscq.h b/src/core/lib/support/mpscq.h
index 24c89f90c9..b3a171678a 100644
--- a/src/core/lib/support/mpscq.h
+++ b/src/core/lib/support/mpscq.h
@@ -37,6 +37,7 @@
 #include <grpc/support/atm.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include "src/core/lib/support/spinlock.h"
 
 // Multiple-producer single-consumer lock free queue, based upon the
 // implementation from Dmitry Vyukov here:
@@ -58,12 +59,34 @@ typedef struct gpr_mpscq {
 void gpr_mpscq_init(gpr_mpscq *q);
 void gpr_mpscq_destroy(gpr_mpscq *q);
 // Push a node
-void gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n);
+// Thread safe - can be called from multiple threads concurrently
+// Returns true if this was possibly the first node (may return true
+// sporadically, will not return false sporadically)
+bool gpr_mpscq_push(gpr_mpscq *q, gpr_mpscq_node *n);
 // Pop a node (returns NULL if no node is ready - which doesn't indicate that
 // the queue is empty!!)
+// Thread compatible - can only be called from one thread at a time
 gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q);
-
 // Pop a node; sets *empty to true if the queue is empty, or false if it is not
 gpr_mpscq_node *gpr_mpscq_pop_and_check_end(gpr_mpscq *q, bool *empty);
 
+// An mpscq with a spinlock: it's safe to pop from multiple threads, but doing
+// only one thread will succeed concurrently
+typedef struct gpr_locked_mpscq {
+  gpr_mpscq queue;
+  gpr_spinlock read_lock;
+} gpr_locked_mpscq;
+
+void gpr_locked_mpscq_init(gpr_locked_mpscq *q);
+void gpr_locked_mpscq_destroy(gpr_locked_mpscq *q);
+// Push a node
+// Thread safe - can be called from multiple threads concurrently
+// Returns true if this was possibly the first node (may return true
+// sporadically, will not return false sporadically)
+bool gpr_locked_mpscq_push(gpr_locked_mpscq *q, gpr_mpscq_node *n);
+// Pop a node (returns NULL if no node is ready - which doesn't indicate that
+// the queue is empty!!)
+// Thread safe - can be called from multiple threads concurrently
+gpr_mpscq_node *gpr_locked_mpscq_pop(gpr_locked_mpscq *q);
+
 #endif /* GRPC_CORE_LIB_SUPPORT_MPSCQ_H */