[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v2 2/2] virtio-blk: Use bdrv_aio_multiwrite
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v2 2/2] virtio-blk: Use bdrv_aio_multiwrite |
Date: |
Tue, 8 Sep 2009 14:49:32 +0200 |
It is quite common for virtio-blk to submit more than one write request in a
row to the qemu block layer. Use bdrv_aio_multiwrite to allow block drivers to
optimize its handling of the requests.
Signed-off-by: Kevin Wolf <address@hidden>
---
hw/virtio-blk.c | 50 ++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 42 insertions(+), 8 deletions(-)
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index c160246..5c88c12 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -252,15 +252,40 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
}
#endif /* __linux__ */
-static void virtio_blk_handle_write(VirtIOBlockReq *req)
+static void do_multiwrite(BlockDriverState *bs, BlockRequest *blkreq,
+ int num_writes)
{
- BlockDriverAIOCB *acb;
+ int i, ret;
+ ret = bdrv_aio_multiwrite(bs, blkreq, num_writes);
+
+ if (ret != 0) {
+ for (i = 0; i < num_writes; i++) {
+ if (blkreq[i].error) {
+ virtio_blk_req_complete(blkreq[i].opaque, VIRTIO_BLK_S_IOERR);
+ }
+ }
+ }
+}
- acb = bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov,
- req->qiov.size / 512, virtio_blk_rw_complete, req);
- if (!acb) {
- virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
+static void virtio_blk_handle_write(BlockRequest *blkreq, int *num_writes,
+ VirtIOBlockReq *req, BlockDriverState **old_bs)
+{
+ if (req->dev->bs != *old_bs || *num_writes == 32) {
+ if (*old_bs != NULL) {
+ do_multiwrite(*old_bs, blkreq, *num_writes);
+ }
+ *num_writes = 0;
+ *old_bs = req->dev->bs;
}
+
+ blkreq[*num_writes].sector = req->out->sector;
+ blkreq[*num_writes].nb_sectors = req->qiov.size / 512;
+ blkreq[*num_writes].qiov = &req->qiov;
+ blkreq[*num_writes].cb = virtio_blk_rw_complete;
+ blkreq[*num_writes].opaque = req;
+ blkreq[*num_writes].error = 0;
+
+ (*num_writes)++;
}
static void virtio_blk_handle_read(VirtIOBlockReq *req)
@@ -278,6 +303,9 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIOBlock *s = to_virtio_blk(vdev);
VirtIOBlockReq *req;
+ BlockRequest blkreq[32];
+ int num_writes = 0;
+ BlockDriverState *old_bs = NULL;
while ((req = virtio_blk_get_request(s))) {
if (req->elem.out_num < 1 || req->elem.in_num < 1) {
@@ -299,13 +327,18 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
} else if (req->out->type & VIRTIO_BLK_T_OUT) {
qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
req->elem.out_num - 1);
- virtio_blk_handle_write(req);
+ virtio_blk_handle_write(blkreq, &num_writes, req, &old_bs);
} else {
qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
req->elem.in_num - 1);
virtio_blk_handle_read(req);
}
}
+
+ if (num_writes > 0) {
+ do_multiwrite(old_bs, blkreq, num_writes);
+ }
+
/*
* FIXME: Want to check for completions before returning to guest mode,
* so cached reads and writes are reported as quickly as possible. But
@@ -324,7 +357,8 @@ static void virtio_blk_dma_restart_bh(void *opaque)
s->rq = NULL;
while (req) {
- virtio_blk_handle_write(req);
+ bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov,
+ req->qiov.size / 512, virtio_blk_rw_complete, req);
req = req->next;
}
}
--
1.6.2.5