Re: [Qemu-devel] [PATCH v5 1/4] block: add the command line support

[Stefan Hajnoczi <stefanha@gmail.com>]

On Tue, Aug 9, 2011 at 5:17 AM, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> wrote:
> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> ---
>  Makefile.objs   |    2 +-
>  blockdev.c      |   39 +++++++++++++++++++++++++++++++++++++++
>  qemu-config.c   |   24 ++++++++++++++++++++++++
>  qemu-option.c   |   17 +++++++++++++++++
>  qemu-option.h   |    1 +
>  qemu-options.hx |    1 +
>  6 files changed, 83 insertions(+), 1 deletions(-)
>
> diff --git a/Makefile.objs b/Makefile.objs
> index 9f99ed4..06f2033 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -23,7 +23,7 @@ block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vv
>  block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o
>  block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
>  block-nested-y += qed-check.o
> -block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
> +block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o blk-queue.o

This does not build:
  LINK  qemu-ga
gcc: error: block/blk-queue.o: No such file or directory

This Makefile.objs change should be in the commit that adds blk-queue.c.

Each patch in a series should compile cleanly and can only depend on
previous patches.  This is important so that git-bisect(1) can be
used, it only works if every commit builds a working program.  It also
makes patch review easier when the patch series builds up logically.

>  block-nested-$(CONFIG_WIN32) += raw-win32.o
>  block-nested-$(CONFIG_POSIX) += raw-posix.o
>  block-nested-$(CONFIG_CURL) += curl.o
> diff --git a/blockdev.c b/blockdev.c
> index c263663..9c78548 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -238,6 +238,10 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>     int on_read_error, on_write_error;
>     const char *devaddr;
>     DriveInfo *dinfo;
> +    BlockIOLimit io_limits;

This structure is not undefined at this point in the patch series.

> +    bool iol_flag = false;
> +    const char *iol_opts[7] = {"bps", "bps_rd", "bps_wr",
> +                                "iops", "iops_rd", "iops_wr"};
>     int is_extboot = 0;
>     int snapshot = 0;
>     int ret;
> @@ -372,6 +376,36 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>         return NULL;
>     }
>
> +    /* disk io throttling */
> +    iol_flag = qemu_opt_io_limits_enable_flag(opts, iol_opts);
> +    if (iol_flag) {
> +        memset(&io_limits, 0, sizeof(BlockIOLimit));
> +
> +        io_limits.bps[BLOCK_IO_LIMIT_TOTAL]  =
> +                           qemu_opt_get_number(opts, "bps", 0);
> +        io_limits.bps[BLOCK_IO_LIMIT_READ]   =
> +                           qemu_opt_get_number(opts, "bps_rd", 0);
> +        io_limits.bps[BLOCK_IO_LIMIT_WRITE]  =
> +                           qemu_opt_get_number(opts, "bps_wr", 0);
> +        io_limits.iops[BLOCK_IO_LIMIT_TOTAL] =
> +                           qemu_opt_get_number(opts, "iops", 0);
> +        io_limits.iops[BLOCK_IO_LIMIT_READ]  =
> +                           qemu_opt_get_number(opts, "iops_rd", 0);
> +        io_limits.iops[BLOCK_IO_LIMIT_WRITE] =
> +                           qemu_opt_get_number(opts, "iops_wr", 0);
> +
> +        if (((io_limits.bps[BLOCK_IO_LIMIT_TOTAL] != 0)
> +            && ((io_limits.bps[BLOCK_IO_LIMIT_READ] != 0)
> +            || (io_limits.bps[BLOCK_IO_LIMIT_WRITE] != 0)))
> +            || ((io_limits.iops[BLOCK_IO_LIMIT_TOTAL] != 0)
> +            && ((io_limits.iops[BLOCK_IO_LIMIT_READ] != 0)
> +            || (io_limits.iops[BLOCK_IO_LIMIT_WRITE] != 0)))) {
> +            error_report("bps(iops) and bps_rd/bps_wr(iops_rd/iops_wr) \
> +                                        cannot be used at the same time");
> +            return NULL;
> +        }
> +    }
> +
>     on_write_error = BLOCK_ERR_STOP_ENOSPC;
>     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
>         if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
> @@ -483,6 +517,11 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>
>     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
>
> +    /* disk I/O throttling */
> +    if (iol_flag) {
> +        bdrv_set_io_limits(dinfo->bdrv, &io_limits);
> +    }

iol_flag and qemu_opt_io_limits_enable_flag() are not necessary.  If
no limits were set then all fields will be 0 (unlimited).

Stefan