[Qemu-devel] [RFC PATCH v7 18/21] replay: thread pool

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

This patch modifies thread pool to allow replaying asynchronous thread tasks
synchronously in replay mode.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 block/raw-posix.c           |    6 ++++-
 block/raw-win32.c           |    4 +++-
 include/block/thread-pool.h |    4 +++-
 replay/replay-events.c      |   11 ++++++++++
 replay/replay-internal.h    |    3 ++-
 replay/replay.h             |    2 ++
 stubs/replay.c              |    4 ++++
 tests/test-thread-pool.c    |    7 ++++--
 thread-pool.c               |   49 ++++++++++++++++++++++++++++++-------------
 9 files changed, 67 insertions(+), 23 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index e51293a..f878e06 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1073,7 +1073,9 @@ static BlockAIOCB *paio_submit(BlockDriverState *bs, int fd,
 
     trace_paio_submit(acb, opaque, sector_num, nb_sectors, type);
     pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
-    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
+    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque,
+                                  qiov ? qiov->replay : false,
+                                  qiov ? qiov->replay_step : 0);
 }
 
 static BlockAIOCB *raw_aio_submit(BlockDriverState *bs,
@@ -1986,7 +1988,7 @@ static BlockAIOCB *hdev_aio_ioctl(BlockDriverState *bs,
     acb->aio_ioctl_buf = buf;
     acb->aio_ioctl_cmd = req;
     pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
-    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
+    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque, false, 0);
 }
 
 #elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 06243d7..7ac693b 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -158,7 +158,9 @@ static BlockAIOCB *paio_submit(BlockDriverState *bs, HANDLE hfile,
 
     trace_paio_submit(acb, opaque, sector_num, nb_sectors, type);
     pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
-    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
+    return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque,
+                                  qiov ? qiov->replay : false,
+                                  qiov ? qiov->replay_step : 0);
 }
 
 int qemu_ftruncate64(int fd, int64_t length)
diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h
index 42eb5e8..801ac00 100644
--- a/include/block/thread-pool.h
+++ b/include/block/thread-pool.h
@@ -29,9 +29,11 @@ void thread_pool_free(ThreadPool *pool);
 
 BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
         ThreadPoolFunc *func, void *arg,
-        BlockCompletionFunc *cb, void *opaque);
+        BlockCompletionFunc *cb, void *opaque,
+        bool replay, uint64_t replay_step);
 int coroutine_fn thread_pool_submit_co(ThreadPool *pool,
         ThreadPoolFunc *func, void *arg);
 void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg);
+void thread_pool_work(ThreadPool *pool, void *r);
 
 #endif
diff --git a/replay/replay-events.c b/replay/replay-events.c
index 1aee0a4..4da5de0 100755
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -12,6 +12,7 @@
 #include "qemu-common.h"
 #include "replay.h"
 #include "replay-internal.h"
+#include "block/thread-pool.h"
 
 typedef struct Event {
     int event_kind;
@@ -39,6 +40,9 @@ static void replay_run_event(Event *event)
     case REPLAY_ASYNC_EVENT_BH:
         aio_bh_call(event->opaque);
         break;
+    case REPLAY_ASYNC_EVENT_THREAD:
+        thread_pool_work((ThreadPool *)event->opaque, event->opaque2);
+        break;
     default:
         fprintf(stderr, "Replay: invalid async event ID (%d) in the queue\n",
                 event->event_kind);
@@ -127,6 +131,11 @@ void replay_add_bh_event(void *bh, uint64_t id)
     replay_add_event_internal(REPLAY_ASYNC_EVENT_BH, bh, NULL, id);
 }
 
+void replay_add_thread_event(void *opaque, void *opaque2, uint64_t id)
+{
+    replay_add_event_internal(REPLAY_ASYNC_EVENT_THREAD, opaque, opaque2, id);
+}
+
 void replay_save_events(int opt)
 {
     qemu_mutex_lock(&lock);
@@ -141,6 +150,7 @@ void replay_save_events(int opt)
             /* save event-specific data */
             switch (event->event_kind) {
             case REPLAY_ASYNC_EVENT_BH:
+            case REPLAY_ASYNC_EVENT_THREAD:
                 replay_put_qword(event->id);
                 break;
             }
@@ -170,6 +180,7 @@ void replay_read_events(int opt)
         /* Execute some events without searching them in the queue */
         switch (read_event_kind) {
         case REPLAY_ASYNC_EVENT_BH:
+        case REPLAY_ASYNC_EVENT_THREAD:
             if (read_id == -1) {
                 read_id = replay_get_qword();
             }
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 6e0c2e9..c32bd9c 100755
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -38,7 +38,8 @@
 /* Asynchronous events IDs */
 
 #define REPLAY_ASYNC_EVENT_BH          0
-#define REPLAY_ASYNC_COUNT             1
+#define REPLAY_ASYNC_EVENT_THREAD      1
+#define REPLAY_ASYNC_COUNT             2
 
 typedef struct ReplayState {
     /*! Cached clock values. */
diff --git a/replay/replay.h b/replay/replay.h
index d3f168d..c72a3fd 100755
--- a/replay/replay.h
+++ b/replay/replay.h
@@ -95,5 +95,7 @@ int replay_checkpoint(unsigned int checkpoint);
 void replay_disable_events(void);
 /*! Adds BH event to the queue */
 void replay_add_bh_event(void *bh, uint64_t id);
+/*! Adds thread event to the queue */
+void replay_add_thread_event(void *pool, void *req, uint64_t id);
 
 #endif
diff --git a/stubs/replay.c b/stubs/replay.c
index 9beecb5..770d59a 100755
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -35,3 +35,7 @@ uint64_t replay_get_current_step(void)
 {
     return 0;
 }
+
+void replay_add_thread_event(void *opaque, void *opaque2, uint64_t id)
+{
+}
diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index 6a0b981..f32594c 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -56,7 +56,7 @@ static void test_submit_aio(void)
 {
     WorkerTestData data = { .n = 0, .ret = -EINPROGRESS };
     data.aiocb = thread_pool_submit_aio(pool, worker_cb, &data,
-                                        done_cb, &data);
+                                        done_cb, &data, false, 0);
 
     /* The callbacks are not called until after the first wait.  */
     active = 1;
@@ -120,7 +120,8 @@ static void test_submit_many(void)
     for (i = 0; i < 100; i++) {
         data[i].n = 0;
         data[i].ret = -EINPROGRESS;
-        thread_pool_submit_aio(pool, worker_cb, &data[i], done_cb, &data[i]);
+        thread_pool_submit_aio(pool, worker_cb, &data[i], done_cb, &data[i],
+                               false, 0);
     }
 
     active = 100;
@@ -149,7 +150,7 @@ static void do_test_cancel(bool sync)
         data[i].n = 0;
         data[i].ret = -EINPROGRESS;
         data[i].aiocb = thread_pool_submit_aio(pool, long_cb, &data[i],
-                                               done_cb, &data[i]);
+                                               done_cb, &data[i], false, 0);
     }
 
     /* Starting the threads may be left to a bottom half.  Let it
diff --git a/thread-pool.c b/thread-pool.c
index e2cac8e..f5a4dac 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -22,6 +22,7 @@
 #include "trace.h"
 #include "block/thread-pool.h"
 #include "qemu/main-loop.h"
+#include "replay/replay.h"
 
 static void do_spawn_thread(ThreadPool *pool);
 
@@ -74,6 +75,27 @@ struct ThreadPool {
     bool stopping;
 };
 
+void thread_pool_work(ThreadPool *pool, void *r)
+{
+    ThreadPoolElement *req = (ThreadPoolElement *)r;
+    int ret;
+    if (replay_mode == REPLAY_MODE_NONE) {
+        qemu_mutex_unlock(&pool->lock);
+    }
+
+    ret = req->func(req->arg);
+    req->ret = ret;
+    /* Write ret before state.  */
+    smp_wmb();
+    req->state = THREAD_DONE;
+
+    if (replay_mode == REPLAY_MODE_NONE) {
+        qemu_mutex_lock(&pool->lock);
+    }
+
+    qemu_bh_schedule(pool->completion_bh);
+}
+
 static void *worker_thread(void *opaque)
 {
     ThreadPool *pool = opaque;
@@ -100,18 +122,12 @@ static void *worker_thread(void *opaque)
         req = QTAILQ_FIRST(&pool->request_list);
         QTAILQ_REMOVE(&pool->request_list, req, reqs);
         req->state = THREAD_ACTIVE;
-        qemu_mutex_unlock(&pool->lock);
-
-        ret = req->func(req->arg);
-
-        req->ret = ret;
-        /* Write ret before state.  */
-        smp_wmb();
-        req->state = THREAD_DONE;
-
-        qemu_mutex_lock(&pool->lock);
 
-        qemu_bh_schedule(pool->completion_bh);
+        if (replay_mode != REPLAY_MODE_NONE && req->common.replay) {
+            replay_add_thread_event(pool, req, req->common.replay_step);
+        } else {
+            thread_pool_work(pool, req);
+        }
     }
 
     pool->cur_threads--;
@@ -235,7 +251,8 @@ static const AIOCBInfo thread_pool_aiocb_info = {
 
 BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
         ThreadPoolFunc *func, void *arg,
-        BlockCompletionFunc *cb, void *opaque)
+        BlockCompletionFunc *cb, void *opaque,
+        bool replay, uint64_t replay_step)
 {
     ThreadPoolElement *req;
 
@@ -244,6 +261,8 @@ BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
     req->arg = arg;
     req->state = THREAD_QUEUED;
     req->pool = pool;
+    req->common.replay = replay;
+    req->common.replay_step = replay_step;
 
     QLIST_INSERT_HEAD(&pool->head, req, all);
 
@@ -254,8 +273,8 @@ BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
         spawn_thread(pool);
     }
     QTAILQ_INSERT_TAIL(&pool->request_list, req, reqs);
-    qemu_mutex_unlock(&pool->lock);
     qemu_sem_post(&pool->sem);
+    qemu_mutex_unlock(&pool->lock);
     return &req->common;
 }
 
@@ -277,14 +296,14 @@ int coroutine_fn thread_pool_submit_co(ThreadPool *pool, ThreadPoolFunc *func,
 {
     ThreadPoolCo tpc = { .co = qemu_coroutine_self(), .ret = -EINPROGRESS };
     assert(qemu_in_coroutine());
-    thread_pool_submit_aio(pool, func, arg, thread_pool_co_cb, &tpc);
+    thread_pool_submit_aio(pool, func, arg, thread_pool_co_cb, &tpc, false, 0);
     qemu_coroutine_yield();
     return tpc.ret;
 }
 
 void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg)
 {
-    thread_pool_submit_aio(pool, func, arg, NULL, NULL);
+    thread_pool_submit_aio(pool, func, arg, NULL, NULL, false, 0);
 }
 
 static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)