block: block: introduce APIs for submitting IO as a batch

This patch introduces three APIs so that following
patches can support queuing I/O requests and submitting them
as a batch for improving I/O performance.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/block.c b/block.c
index f80e2b2b58bbcec7207c47f794883f568d8b975b..8800a6b5b37215f8c264676dce5857e2d206a8b4 100644 (file)
--- a/block.c
+++ b/block.c
@@ -1905,6 +1905,7 @@ void bdrv_drain_all(void)
             bool bs_busy;
 
             aio_context_acquire(aio_context);
+            bdrv_flush_io_queue(bs);
             bdrv_start_throttled_reqs(bs);
             bs_busy = bdrv_requests_pending(bs);
             bs_busy |= aio_poll(aio_context, bs_busy);
@@ -5782,3 +5783,33 @@ BlockDriverState *check_to_replace_node(const char *node_name, Error **errp)
 
     return to_replace_bs;
 }
+
+void bdrv_io_plug(BlockDriverState *bs)
+{
+    BlockDriver *drv = bs->drv;
+    if (drv && drv->bdrv_io_plug) {
+        drv->bdrv_io_plug(bs);
+    } else if (bs->file) {
+        bdrv_io_plug(bs->file);
+    }
+}
+
+void bdrv_io_unplug(BlockDriverState *bs)
+{
+    BlockDriver *drv = bs->drv;
+    if (drv && drv->bdrv_io_unplug) {
+        drv->bdrv_io_unplug(bs);
+    } else if (bs->file) {
+        bdrv_io_unplug(bs->file);
+    }
+}
+
+void bdrv_flush_io_queue(BlockDriverState *bs)
+{
+    BlockDriver *drv = bs->drv;
+    if (drv && drv->bdrv_flush_io_queue) {
+        drv->bdrv_flush_io_queue(bs);
+    } else if (bs->file) {
+        bdrv_flush_io_queue(bs->file);
+    }
+}

diff --git a/include/block/block.h b/include/block/block.h
index baecc26dfc021589fa1aeabf29d99920e54b45d8..32d36760fdeff83b13089cd2d3b5c63cf10759f2 100644 (file)
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -584,4 +584,8 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs);
  */
 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
 
+void bdrv_io_plug(BlockDriverState *bs);
+void bdrv_io_unplug(BlockDriverState *bs);
+void bdrv_flush_io_queue(BlockDriverState *bs);
+
 #endif

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8f8e65e763f8049856e5ee006e882b40f76ce81f..f6c3befed807ec09b5bdead346fa78d69d6aacbf 100644 (file)
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -261,6 +261,11 @@ struct BlockDriver {
     void (*bdrv_attach_aio_context)(BlockDriverState *bs,
                                     AioContext *new_context);
 
+    /* io queue for linux-aio */
+    void (*bdrv_io_plug)(BlockDriverState *bs);
+    void (*bdrv_io_unplug)(BlockDriverState *bs);
+    void (*bdrv_flush_io_queue)(BlockDriverState *bs);
+
     QLIST_ENTRY(BlockDriver) list;
 };