From 8c690c76ec455386cfee6757ae731e24dca40400 Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Mon, 18 Nov 2019 14:08:11 +0300
Subject: [PATCH] Wakeup ring loop

---
 blockstore.cpp      |  3 ++-
 blockstore_init.cpp |  1 +
 ringloop.cpp        | 30 ++++++++++++++++++------------
 ringloop.h          |  6 ++++--
 test_blockstore.cpp | 12 +++++++++---
 5 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/blockstore.cpp b/blockstore.cpp
index 78a4a7bb..4a9a77ed 100644
--- a/blockstore.cpp
+++ b/blockstore.cpp
@@ -48,7 +48,7 @@ blockstore::~blockstore()
 {
     delete flusher;
     free(zero_object);
-    ringloop->unregister_consumer(ring_consumer.number);
+    ringloop->unregister_consumer(ring_consumer);
     if (data_fd >= 0)
         close(data_fd);
     if (meta_fd >= 0 && meta_fd != data_fd)
@@ -246,5 +246,6 @@ int blockstore::enqueue_op(blockstore_operation *op)
     {
         enqueue_write(op);
     }
+    ringloop->wakeup(ring_consumer);
     return 0;
 }
diff --git a/blockstore_init.cpp b/blockstore_init.cpp
index c82d7c31..9067db55 100644
--- a/blockstore_init.cpp
+++ b/blockstore_init.cpp
@@ -254,6 +254,7 @@ int blockstore_init_journal::loop()
         bs->journal.crc32_last = crc32_last;
         journal_buffer = NULL;
         step = 100;
+        return 0;
     }
     return 1;
 }
diff --git a/ringloop.cpp b/ringloop.cpp
index 9e3b9c55..cf495fa0 100644
--- a/ringloop.cpp
+++ b/ringloop.cpp
@@ -27,17 +27,22 @@ int ring_loop_t::register_consumer(ring_consumer_t & consumer)
     return consumer.number;
 }
 
-void ring_loop_t::unregister_consumer(int number)
+void ring_loop_t::wakeup(ring_consumer_t & consumer)
 {
-    if (number < consumers.size())
+    loop_again = true;
+}
+
+void ring_loop_t::unregister_consumer(ring_consumer_t & consumer)
+{
+    if (consumer.number >= 0 && consumer.number < consumers.size())
     {
-        consumers[number].loop = NULL;
+        consumers[consumer.number].loop = NULL;
+        consumer.number = -1;
     }
 }
 
-void ring_loop_t::loop(bool sleep)
+void ring_loop_t::loop()
 {
-    // FIXME: we should loop until all "coroutines" are suspended. currently we loop only once before sleeping
     struct io_uring_cqe *cqe;
     while (!io_uring_peek_cqe(&ring, &cqe))
     {
@@ -49,12 +54,13 @@ void ring_loop_t::loop(bool sleep)
         }
         io_uring_cqe_seen(&ring, cqe);
     }
-    for (int i = 0; i < consumers.size(); i++)
+    do
     {
-        consumers[i].loop();
-    }
-    if (sleep)
-    {
-        io_uring_wait_cqe(&ring, &cqe);
-    }
+        loop_again = false;
+        for (int i = 0; i < consumers.size(); i++)
+        {
+            consumers[i].loop();
+        }
+    } while (loop_again);
+    io_uring_wait_cqe(&ring, &cqe);
 }
diff --git a/ringloop.h b/ringloop.h
index 5b9ad93f..3701cc7a 100644
--- a/ringloop.h
+++ b/ringloop.h
@@ -120,6 +120,7 @@ class ring_loop_t
 {
     std::vector<ring_consumer_t> consumers;
     struct ring_data_t *ring_data;
+    bool loop_again;
 public:
     struct io_uring ring;
     ring_loop_t(int qd);
@@ -134,8 +135,9 @@ public:
         return sqe;
     }
     int register_consumer(ring_consumer_t & consumer);
-    void unregister_consumer(int number);
-    void loop(bool sleep);
+    void wakeup(ring_consumer_t & consumer);
+    void unregister_consumer(ring_consumer_t & consumer);
+    void loop();
     inline int submit()
     {
         return io_uring_submit(&ring);
diff --git a/test_blockstore.cpp b/test_blockstore.cpp
index 27bdd176..96b3e6f6 100644
--- a/test_blockstore.cpp
+++ b/test_blockstore.cpp
@@ -36,7 +36,7 @@ public:
 
     ~timerfd_interval()
     {
-        ringloop->unregister_consumer(consumer.number);
+        ringloop->unregister_consumer(consumer);
         close(timerfd);
     }
 
@@ -94,16 +94,22 @@ int main(int narg, char *args[])
     {
         printf("completed %d\n", op->retval);
     };
+    ring_consumer_t main_cons;
     bool bs_was_done = false;
-    while (true)
+    main_cons.loop = [&]()
     {
         bool bs_done = bs->is_started();
         if (bs_done && !bs_was_done)
         {
+            printf("init completed\n");
             bs->enqueue_op(&op);
             bs_was_done = true;
         }
-        ringloop->loop(true);
+    };
+    ringloop->register_consumer(main_cons);
+    while (true)
+    {
+        ringloop->loop();
     }
     delete bs;
     delete ringloop;