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Re: [libvirt] [PATCH 1/5] vcpupin: introduce the new libvirt API (virDomainGetVcpupinInfo)



On Fri, Jun 24, 2011 at 05:56:21PM +0900, Taku Izumi wrote:
> 
> This patch introduces a new libvirt API (virDomainGetVcpupinInfo).
> 
> We can use virDomainGetVcpus API to retrieve CPU affinity information,
> but can't use this API against inactive domains (at least in case of KVM).
> There is the companion API of this, whose name is virDomainGetVcpusFlags. 
> However its signature is different from what everyone expect, so we can't use
> this to retrieve it either. 
> 
> The virDomainGetVcpupinInfo is the new API to retrieve CPU affinity information
> of active and inactive domains.
> 
> 
> Signed-off-by: Taku Izumi <izumi taku jp fujitsu com>
> ---
>  include/libvirt/libvirt.h.in |    6 +++
>  src/driver.h                 |    8 ++++
>  src/libvirt.c                |   69 +++++++++++++++++++++++++++++++++++++++++++
>  src/libvirt_public.syms      |    1 
>  4 files changed, 84 insertions(+)
> 
> Index: libvirt/include/libvirt/libvirt.h.in
> ===================================================================
> --- libvirt.orig/include/libvirt/libvirt.h.in
> +++ libvirt/include/libvirt/libvirt.h.in
> @@ -1265,6 +1265,12 @@ int                     virDomainPinVcpu
>                                                   int maplen,
>                                                   unsigned int flags);
>  
> +int                     virDomainGetVcpupinInfo (virDomainPtr domain,
> +                                                 int maxinfo,
> +                                                 unsigned char *cpumaps,
> +                                                 int maplen,
> +                                                 unsigned int flags);
> +

 API looks fine to me

[...]
> --- libvirt.orig/src/libvirt.c
> +++ libvirt/src/libvirt.c
> @@ -7087,6 +7087,75 @@ error:
>  }
>  
>  /**
> + * virDomainGetVcpupinInfo:
> + * @domain: pointer to domain object, or NULL for Domain0
> + * @maxinfo: the number of cpumap
> + * @cpumaps: pointer to a bit map of real CPUs for all vcpus of this
> + *     domain (in 8-bit bytes) (OUT)
> + *     It's assumed there is <maxinfo> cpumap in cpumaps array.
> + *     The memory allocated to cpumaps must be (maxinfo * maplen) bytes
> + *     (ie: calloc(maxinfo, maplen)).
> + *     One cpumap inside cpumaps has the format described in
> + *     virDomainPinVcpu() API.
> + *     Must not be NULL.
> + * @maplen: the number of bytes in one cpumap, from 1 up to size of CPU map.
> + *     Must be positive.
> + * @flags: an OR'ed set of virDomainModificationImpact
> + *     Must not be specified VIR_DOMAIN_AFFECT_LIVE and
> + *     VIR_DOMAIN_AFFECT_CONFIG concurrently!
> + *
> + * Query the CPU affinity setting of all virtual CPUs of domain, store it
> + * in cpumaps.
> + *
> + * Returns the number of virtual CPUs in case of success,
> + * -1 in case of failure.
> + */
> +int
> +virDomainGetVcpupinInfo (virDomainPtr domain, int maxinfo,
> +                         unsigned char *cpumaps, int maplen, unsigned int flags)
> +{
> +    virConnectPtr conn;
> +
> +    VIR_DOMAIN_DEBUG(domain, "maxinfo=%d, cpumaps=%p, maplen=%d, flags=%u",
> +                     maxinfo, cpumaps, maplen, flags);
> +
> +    virResetLastError();
> +
> +    if (!VIR_IS_CONNECTED_DOMAIN(domain)) {
> +        virLibDomainError(VIR_ERR_INVALID_DOMAIN, __FUNCTION__);
> +        virDispatchError(NULL);
> +        return -1;
> +    }
> +
> +    if (maxinfo < 1) {
> +        virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
> +        goto error;
> +    }

  We don't check for read-only here, but the semantic is purely reading
that's normal

> +    if ((cpumaps == NULL) || (cpumaps && maplen <= 0)) {
> +        virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
> +        goto error;
> +    }
> +
> +    conn = domain->conn;
> +
> +    if (conn->driver->domainGetVcpupinInfo) {
> +        int ret;
> +        ret = conn->driver->domainGetVcpupinInfo (domain, maxinfo,
> +                                                  cpumaps, maplen, flags);
> +        if (ret < 0)
> +            goto error;
> +        return ret;
> +    }
> +
> +    virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
> +
> +error:
> +    virDispatchError(domain->conn);
> +    return -1;
> +}
> +
> +/**
>   * virDomainGetVcpus:
>   * @domain: pointer to domain object, or NULL for Domain0
>   * @info: pointer to an array of virVcpuInfo structures (OUT)

  Okay ACK on the API principle from me,

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/


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