Commit 294cc35f authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block: Add wr_highest_sector blockstat 



This adds the wr_highest_sector blockstat which implements what is generally
known as the high watermark. It is the highest offset of a sector written to
the respective BlockDriverState since it has been opened.

The query-blockstat QMP command is extended to add this value to the result,
and also to add the statistics of the underlying protocol in a new "parent"
field. Note that to get the "high watermark" of a qcow2 image, you need to look
into the wr_highest_sector field of the parent (which can be a file, a
host_device, ...). The wr_highest_sector of the qcow2 BlockDriverState itself
is the highest offset on the _virtual_ disk that the guest has written to.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 419b19d9

block.c

+58 −15
Original line number Diff line number Diff line
@@ -880,6 +880,10 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num, 
        set_dirty_bitmap(bs, sector_num, nb_sectors, 1);

    }



    if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {

        bs->wr_highest_sector = sector_num + nb_sectors - 1;

    }



    return drv->bdrv_write(bs, sector_num, buf, nb_sectors);

}
@@ -1530,6 +1534,35 @@ void bdrv_stats_print(Monitor *mon, const QObject *data) 
    qlist_iter(qobject_to_qlist(data), bdrv_stats_iter, mon);

}



static QObject* bdrv_info_stats_bs(BlockDriverState *bs)

{

    QObject *res;

    QDict *dict;



    res = qobject_from_jsonf("{ 'stats': {"

                             "'rd_bytes': %" PRId64 ","

                             "'wr_bytes': %" PRId64 ","

                             "'rd_operations': %" PRId64 ","

                             "'wr_operations': %" PRId64 ","

                             "'wr_highest_offset': %" PRId64

                             "} }",

                             bs->rd_bytes, bs->wr_bytes,

                             bs->rd_ops, bs->wr_ops,

                             bs->wr_highest_sector * 512);

    dict  = qobject_to_qdict(res);



    if (*bs->device_name) {

        qdict_put(dict, "device", qstring_from_str(bs->device_name));

    }



    if (bs->file) {

        QObject *parent = bdrv_info_stats_bs(bs->file);

        qdict_put_obj(dict, "parent", parent);

    }



    return res;

}



/**

 * bdrv_info_stats(): show block device statistics

 *
@@ -1544,6 +1577,11 @@ void bdrv_stats_print(Monitor *mon, const QObject *data) 
 *     - "wr_bytes": bytes written

 *     - "rd_operations": read operations

 *     - "wr_operations": write operations

 *     - "wr_highest_offset": Highest offset of a sector written since the

 *       BlockDriverState has been opened

 *     - "parent": Contains recursively the statistics of the underlying

 *       protocol (e.g. the host file for a qcow2 image). If there is no

 *       underlying protocol, this field is omitted.

 *

 * Example:

 *
@@ -1551,12 +1589,22 @@ void bdrv_stats_print(Monitor *mon, const QObject *data) 
 *               "stats": { "rd_bytes": 512,

 *                          "wr_bytes": 0,

 *                          "rd_operations": 1,

 *                          "wr_operations": 0 } },

 *                          "wr_operations": 0,

 *                          "wr_highest_offset": 0,

 *                          "parent": {

 *                              "stats": { "rd_bytes": 1024,

 *                                         "wr_bytes": 0,

 *                                         "rd_operations": 2,

 *                                         "wr_operations": 0,

 *                                         "wr_highest_offset": 0,

 *                              }

 *                          } } },

 *   { "device": "ide1-cd0",

 *               "stats": { "rd_bytes": 0,

 *                          "wr_bytes": 0,

 *                          "rd_operations": 0,

 *                          "wr_operations": 0 } } ]

 *                          "wr_operations": 0,

 *                          "wr_highest_offset": 0 } },

 */

void bdrv_info_stats(Monitor *mon, QObject **ret_data)

{
@@ -1567,15 +1615,7 @@ void bdrv_info_stats(Monitor *mon, QObject **ret_data) 
    devices = qlist_new();



    QTAILQ_FOREACH(bs, &bdrv_states, list) {

        obj = qobject_from_jsonf("{ 'device': %s, 'stats': {"

                                 "'rd_bytes': %" PRId64 ","

                                 "'wr_bytes': %" PRId64 ","

                                 "'rd_operations': %" PRId64 ","

                                 "'wr_operations': %" PRId64

                                 "} }",

                                 bs->device_name,

                                 bs->rd_bytes, bs->wr_bytes,

                                 bs->rd_ops, bs->wr_ops);

        obj = bdrv_info_stats_bs(bs);

        qlist_append_obj(devices, obj);

    }
@@ -1837,6 +1877,9 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, 
        /* Update stats even though technically transfer has not happened. */

        bs->wr_bytes += (unsigned) nb_sectors * BDRV_SECTOR_SIZE;

        bs->wr_ops ++;

        if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {

            bs->wr_highest_sector = sector_num + nb_sectors - 1;

        }

    }



    return ret;

block_int.h

+1 −0
Original line number Diff line number Diff line
@@ -167,6 +167,7 @@ struct BlockDriverState { 
    uint64_t wr_bytes;

    uint64_t rd_ops;

    uint64_t wr_ops;

    uint64_t wr_highest_sector;



    /* Whether the disk can expand beyond total_sectors */

    int growable;