Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into staging

Pull request

- Add new thread-pool-min/thread-pool-max parameters to control the thread pool
  used for async I/O.

- Fix virtio-scsi IOThread 100% CPU consumption QEMU 7.0 regression.

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# gpg: Signature made Mon 09 May 2022 05:52:56 AM PDT
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# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]

* tag 'block-pull-request' of https://gitlab.com/stefanha/qemu:
  virtio-scsi: move request-related items from .h to .c
  virtio-scsi: clean up virtio_scsi_handle_cmd_vq()
  virtio-scsi: clean up virtio_scsi_handle_ctrl_vq()
  virtio-scsi: clean up virtio_scsi_handle_event_vq()
  virtio-scsi: don't waste CPU polling the event virtqueue
  virtio-scsi: fix ctrl and event handler functions in dataplane mode
  util/event-loop-base: Introduce options to set the thread pool size
  util/main-loop: Introduce the main loop into QOM
  Introduce event-loop-base abstract class

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

7 files changed, 67 insertions, 47 deletions

diff --git a/include/block/aio.h b/include/block/aio.h
index 5634173b12..d128558f1d 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -192,6 +192,8 @@ struct AioContext {
     QSLIST_HEAD(, Coroutine) scheduled_coroutines;
     QEMUBH *co_schedule_bh;
 
+    int thread_pool_min;
+    int thread_pool_max;
     /* Thread pool for performing work and receiving completion callbacks.
      * Has its own locking.
      */
@@ -769,4 +771,12 @@ void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns,
 void aio_context_set_aio_params(AioContext *ctx, int64_t max_batch,
                                 Error **errp);
 
+/**
+ * aio_context_set_thread_pool_params:
+ * @ctx: the aio context
+ * @min: min number of threads to have readily available in the thread pool
+ * @min: max number of threads the thread pool can contain
+ */
+void aio_context_set_thread_pool_params(AioContext *ctx, int64_t min,
+                                        int64_t max, Error **errp);
 #endif
diff --git a/include/block/thread-pool.h b/include/block/thread-pool.h
index 7dd7d730a0..2020bcc92d 100644
--- a/include/block/thread-pool.h
+++ b/include/block/thread-pool.h
@@ -20,6 +20,8 @@
 
 #include "block/block.h"
 
+#define THREAD_POOL_MAX_THREADS_DEFAULT         64
+
 typedef int ThreadPoolFunc(void *opaque);
 
 typedef struct ThreadPool ThreadPool;
@@ -33,5 +35,6 @@ BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
 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_update_params(ThreadPool *pool, struct AioContext *ctx);
 
 #endif
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index 0997313f0a..a36aad9c86 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -92,42 +92,6 @@ struct VirtIOSCSI {
     uint32_t host_features;
 };
 
-typedef struct VirtIOSCSIReq {
-    /* Note:
-     * - fields up to resp_iov are initialized by virtio_scsi_init_req;
-     * - fields starting at vring are zeroed by virtio_scsi_init_req.
-     * */
-    VirtQueueElement elem;
-
-    VirtIOSCSI *dev;
-    VirtQueue *vq;
-    QEMUSGList qsgl;
-    QEMUIOVector resp_iov;
-
-    union {
-        /* Used for two-stage request submission */
-        QTAILQ_ENTRY(VirtIOSCSIReq) next;
-
-        /* Used for cancellation of request during TMFs */
-        int remaining;
-    };
-
-    SCSIRequest *sreq;
-    size_t resp_size;
-    enum SCSIXferMode mode;
-    union {
-        VirtIOSCSICmdResp     cmd;
-        VirtIOSCSICtrlTMFResp tmf;
-        VirtIOSCSICtrlANResp  an;
-        VirtIOSCSIEvent       event;
-    } resp;
-    union {
-        VirtIOSCSICmdReq      cmd;
-        VirtIOSCSICtrlTMFReq  tmf;
-        VirtIOSCSICtrlANReq   an;
-    } req;
-} VirtIOSCSIReq;
-
 static inline void virtio_scsi_acquire(VirtIOSCSI *s)
 {
     if (s->ctx) {
@@ -149,13 +113,6 @@ void virtio_scsi_common_realize(DeviceState *dev,
                                 Error **errp);
 
 void virtio_scsi_common_unrealize(DeviceState *dev);
-bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq);
-bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq);
-bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq);
-void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req);
-void virtio_scsi_free_req(VirtIOSCSIReq *req);
-void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
-                            uint32_t event, uint32_t reason);
 
 void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp);
 int virtio_scsi_dataplane_start(VirtIODevice *s);
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index b31c4507f5..b62a35fdca 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -317,6 +317,7 @@ EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq);
 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled);
 void virtio_queue_host_notifier_read(EventNotifier *n);
 void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx);
+void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx);
 void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx);
 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector);
 VirtQueue *virtio_vector_next_queue(VirtQueue *vq);
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index 89bd9edefb..5518845299 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -26,9 +26,19 @@
 #define QEMU_MAIN_LOOP_H
 
 #include "block/aio.h"
+#include "qom/object.h"
+#include "sysemu/event-loop-base.h"
 
 #define SIG_IPI SIGUSR1
 
+#define TYPE_MAIN_LOOP  "main-loop"
+OBJECT_DECLARE_TYPE(MainLoop, MainLoopClass, MAIN_LOOP)
+
+struct MainLoop {
+    EventLoopBase parent_obj;
+};
+typedef struct MainLoop MainLoop;
+
 /**
  * qemu_init_main_loop: Set up the process so that it can run the main loop.
  *
diff --git a/include/sysemu/event-loop-base.h b/include/sysemu/event-loop-base.h
new file mode 100644
index 0000000000..2748bf6ae1
--- /dev/null
+++ b/include/sysemu/event-loop-base.h
@@ -0,0 +1,41 @@
+/*
+ * QEMU event-loop backend
+ *
+ * Copyright (C) 2022 Red Hat Inc
+ *
+ * Authors:
+ *  Nicolas Saenz Julienne <nsaenzju@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#ifndef QEMU_EVENT_LOOP_BASE_H
+#define QEMU_EVENT_LOOP_BASE_H
+
+#include "qom/object.h"
+#include "block/aio.h"
+#include "qemu/typedefs.h"
+
+#define TYPE_EVENT_LOOP_BASE         "event-loop-base"
+OBJECT_DECLARE_TYPE(EventLoopBase, EventLoopBaseClass,
+                    EVENT_LOOP_BASE)
+
+struct EventLoopBaseClass {
+    ObjectClass parent_class;
+
+    void (*init)(EventLoopBase *base, Error **errp);
+    void (*update_params)(EventLoopBase *base, Error **errp);
+    bool (*can_be_deleted)(EventLoopBase *base);
+};
+
+struct EventLoopBase {
+    Object parent;
+
+    /* AioContext AIO engine parameters */
+    int64_t aio_max_batch;
+
+    /* AioContext thread pool parameters */
+    int64_t thread_pool_min;
+    int64_t thread_pool_max;
+};
+#endif
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index 7f714bd136..8f8601d6ab 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -17,11 +17,12 @@
 #include "block/aio.h"
 #include "qemu/thread.h"
 #include "qom/object.h"
+#include "sysemu/event-loop-base.h"
 
 #define TYPE_IOTHREAD "iothread"
 
 struct IOThread {
-    Object parent_obj;
+    EventLoopBase parent_obj;
 
     QemuThread thread;
     AioContext *ctx;
@@ -37,9 +38,6 @@ struct IOThread {
     int64_t poll_max_ns;
     int64_t poll_grow;
     int64_t poll_shrink;
-
-    /* AioContext AIO engine parameters */
-    int64_t aio_max_batch;
 };
 typedef struct IOThread IOThread;