commit 448ad91db4a560c01f89bd6f7e4bec7d869926a5
author Ming Lei <ming.lei@canonical.com> Fri Jul 04 18:04:33 2014 +0800
committer Stefan Hajnoczi <stefanha@redhat.com> Mon Jul 07 11:05:17 2014 +0200
tree a326648a01081363fdcc6ece7ef45b34e3a0b5eb
parent 5a18e67dfd515992076c5fcae47035fdd3ed2462

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>

block.c

diff --git a/block.c b/block.c
index f80e2b2..8800a6b 100644
--- a/block.c
+++ b/block.c
@@ -1905,6 +1905,7 @@
             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 @@
 
     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);
+    }
+}

include/block/block.h

diff --git a/include/block/block.h b/include/block/block.h
index baecc26..32d3676 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -584,4 +584,8 @@
  */
 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

include/block/block_int.h

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8f8e65e..f6c3bef 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -261,6 +261,11 @@
     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;
 };