On Mon, Nov 21, 2016 at 06:35:48PM -0500, John Ferlan wrote:
> Rather than using negative logic and setting the maxparams to a lesser
> value based on which capabilities exist, alter the logic to modify the
> maxparams based on a base value plus the found capabilities. Reduces the
> chance that some backported feature produces an incorrect value.
>
> Signed-off-by: John Ferlan <jferlan@xxxxxxxxxx>
> ---
> src/qemu/qemu_driver.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d039255..87d219f 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -112,9 +112,12 @@ VIR_LOG_INIT("qemu.qemu_driver");
>
> #define QEMU_NB_MEM_PARAM 3
>
> -#define QEMU_NB_BLOCK_IO_TUNE_PARAM 6
> -#define QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX 13
> -#define QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX_LENGTH 19
> +#define QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS 6
> +#define QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS 7
> +#define QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS 6
> +#define QEMU_NB_BLOCK_IO_TUNE_ALL_PARAMS (QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS + \
> + QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS + \
> + QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS)
>
> #define QEMU_NB_NUMA_PARAM 2
>
> @@ -17719,7 +17722,7 @@ qemuDomainGetBlockIoTune(virDomainPtr dom,
> virDomainBlockIoTuneInfo reply;
> char *device = NULL;
> int ret = -1;
> - int maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX_LENGTH;
> + int maxparams;
>
> virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
> VIR_DOMAIN_AFFECT_CONFIG |
> @@ -17753,11 +17756,13 @@ qemuDomainGetBlockIoTune(virDomainPtr dom,
> goto endjob;
> }
>
> - if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX))
> - maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM;
> - else if (!virQEMUCapsGet(priv->qemuCaps,
> - QEMU_CAPS_DRIVE_IOTUNE_MAX_LENGTH))
> - maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX;
> + maxparams = QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS;
> + if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX))
> + maxparams += QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS;
> + if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX_LENGTH))
> + maxparams += QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS;
> + } else {
> + maxparams = QEMU_NB_BLOCK_IO_TUNE_ALL_PARAMS;
> }
>
I'm curious about the else branch. Can you elaborate more on why do you assume
qemu supports all the features when you retrieve a persistentdef vs livedef?
From what I understand, this is one of the APIs that you have to call twice,
since the RPC layer does not allocate a structure of an appropriate size
automatically. So with the first run, you say, please allocate a structure of
size maxparams equal _ALL_PARAMS (without knowing that qemu actually supports
all these features) and rerun.
Then during the second run, you run BLOCK_IOTUNE_ASSIGN on all of them, what am
I missing?
Erik
> if (*nparams == 0) {
> --
> 2.7.4
>
> --
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