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block: explicit I/O accounting

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Decouple the I/O accounting from bdrv_aio_readv/writev/flush and
make the hardware models call directly into the accounting helpers.

This means:
 - we do not count internal requests from image formats in addition
   to guest originating I/O
 - we do not double count I/O ops if the device model handles it
   chunk wise
 - we only account I/O once it actuall is done
 - can extent I/O accounting to synchronous or coroutine I/O easily
 - implement I/O latency tracking easily (see the next patch)

I've conveted the existing device model callers to the new model,
device models that are using synchronous I/O and weren't accounted
before haven't been updated yet.  Also scsi hasn't been converted
to the end-to-end accounting as I want to defer that after the pending
scsi layer overhaul.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Christoph Hellwig 2011-08-25 08:26:01 +02:00 • committed by Kevin Wolf
parent 2f4b759367
commit a597e79ce1
12 changed files with 171 additions and 50 deletions
Download patch file Download diff file Expand all files Collapse all files

20
hw/virtio-blk.c
View file

@ -47,6 +47,7 @@ typedef struct VirtIOBlockReq
struct virtio_scsi_inhdr *scsi;
QEMUIOVector qiov;
struct VirtIOBlockReq *next;
BlockAcctCookie acct;
} VirtIOBlockReq;
static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
@ -58,8 +59,6 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
stb_p(&req->in->status, status);
virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
virtio_notify(&s->vdev, s->vq);
g_free(req);
}
static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
@ -81,6 +80,8 @@ static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
vm_stop(VMSTOP_DISKFULL);
} else {
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
bdrv_acct_done(s->bs, &req->acct);
g_free(req);
bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, is_read);
}
@ -100,6 +101,8 @@ static void virtio_blk_rw_complete(void *opaque, int ret)
}
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
bdrv_acct_done(req->dev->bs, &req->acct);
g_free(req);
}
static void virtio_blk_flush_complete(void *opaque, int ret)
@ -113,6 +116,8 @@ static void virtio_blk_flush_complete(void *opaque, int ret)
}
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
bdrv_acct_done(req->dev->bs, &req->acct);
g_free(req);
}
static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
@ -155,6 +160,7 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
*/
if (req->elem.out_num < 2 || req->elem.in_num < 3) {
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
g_free(req);
return;
}
@ -163,6 +169,7 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
*/
if (req->elem.out_num > 2 && req->elem.in_num > 3) {
virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
g_free(req);
return;
}
@ -229,11 +236,13 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
stl_p(&req->scsi->data_len, hdr.dxfer_len);
virtio_blk_req_complete(req, status);
g_free(req);
}
#else
static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
{
virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
g_free(req);
}
#endif /* __linux__ */
@ -266,6 +275,8 @@ static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
{
BlockDriverAIOCB *acb;
bdrv_acct_start(req->dev->bs, &req->acct, 0, BDRV_ACCT_FLUSH);
/*
* Make sure all outstanding writes are posted to the backing device.
*/
@ -284,6 +295,8 @@ static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
sector = ldq_p(&req->out->sector);
bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE);
trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
if (sector & req->dev->sector_mask) {
@ -317,6 +330,8 @@ static void virtio_blk_handle_read(VirtIOBlockReq *req)
sector = ldq_p(&req->out->sector);
bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ);
if (sector & req->dev->sector_mask) {
virtio_blk_rw_complete(req, -EIO);
return;
@ -370,6 +385,7 @@ static void virtio_blk_handle_request(VirtIOBlockReq *req,
s->serial ? s->serial : "",
MIN(req->elem.in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES));
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
g_free(req);
} else if (type & VIRTIO_BLK_T_OUT) {
qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
req->elem.out_num - 1);