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



On 06/24/2011 02:56 AM, 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. 

Actually not a companion API.  virDomainGetVcpusFlags is a counterpart
to virDomainGetMaxVcpus.

The choice of naming isn't perfect, but we're stuck with it.

> 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.
> 

>                                                   unsigned int flags);
>  
> +int                     virDomainGetVcpupinInfo (virDomainPtr domain,
> +                                                 int maxinfo,

See other email about this naming choice.

> --- libvirt.orig/src/libvirt_public.syms
> +++ libvirt/src/libvirt_public.syms
> @@ -467,6 +467,7 @@ LIBVIRT_0.9.3 {
>          virEventUpdateTimeout;
>          virNodeGetCPUStats;
>          virNodeGetMemoryStats;
> +        virDomainGetVcpupinInfo;

I'm a fan of sorting, as others on this list will attest :)

> + * @flags: an OR'ed set of virDomainModificationImpact
> + *     Must not be specified VIR_DOMAIN_AFFECT_LIVE and
> + *     VIR_DOMAIN_AFFECT_CONFIG concurrently!

Grammar was a bit awkward, and ! is usually overkill in documentation.

> + *
> + * 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;
> +    }
> +
> +    if ((cpumaps == NULL) || (cpumaps && maplen <= 0)) {

The 'cpumaps &&' check is redundant...

> +        virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);

...and this error is the same, so I merged some code.

Here's what I'm squashing in:

diff --git i/include/libvirt/libvirt.h.in w/include/libvirt/libvirt.h.in
index 2c78f1f..4f9f158 100644
--- i/include/libvirt/libvirt.h.in
+++ w/include/libvirt/libvirt.h.in
@@ -1267,7 +1267,7 @@ int                     virDomainPinVcpuFlags
(virDomainPtr domain,
                                                  unsigned int flags);

 int                     virDomainGetVcpupinInfo (virDomainPtr domain,
-                                                 int maxinfo,
+                                                 int ncpumaps,
                                                  unsigned char *cpumaps,
                                                  int maplen,
                                                  unsigned int flags);
diff --git i/src/libvirt.c w/src/libvirt.c
index e289fee..3f9585b 100644
--- i/src/libvirt.c
+++ w/src/libvirt.c
@@ -7111,20 +7111,20 @@ error:
 /**
  * virDomainGetVcpupinInfo:
  * @domain: pointer to domain object, or NULL for Domain0
- * @maxinfo: the number of cpumap
+ * @ncpumaps: the number of cpumap (listed first to match
virDomainGetVcpus)
  * @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)).
+ *     It's assumed there is <ncpumaps> cpumap in cpumaps array.
+ *     The memory allocated to cpumaps must be (ncpumaps * maplen) bytes
+ *     (ie: calloc(ncpumaps, 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!
+ *     Must not be 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.
@@ -7133,13 +7133,13 @@ error:
  * -1 in case of failure.
  */
 int
-virDomainGetVcpupinInfo (virDomainPtr domain, int maxinfo,
+virDomainGetVcpupinInfo (virDomainPtr domain, int ncpumaps,
                          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);
+    VIR_DOMAIN_DEBUG(domain, "ncpumaps=%d, cpumaps=%p, maplen=%d,
flags=%u",
+                     ncpumaps, cpumaps, maplen, flags);

     virResetLastError();

@@ -7149,12 +7149,7 @@ virDomainGetVcpupinInfo (virDomainPtr domain, int
maxinfo,
         return -1;
     }

-    if (maxinfo < 1) {
-        virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
-        goto error;
-    }
-
-    if ((cpumaps == NULL) || (cpumaps && maplen <= 0)) {
+    if (ncpumaps < 1 || !cpumaps || maplen <= 0) {
         virLibDomainError(VIR_ERR_INVALID_ARG, __FUNCTION__);
         goto error;
     }
@@ -7163,7 +7158,7 @@ virDomainGetVcpupinInfo (virDomainPtr domain, int
maxinfo,

     if (conn->driver->domainGetVcpupinInfo) {
         int ret;
-        ret = conn->driver->domainGetVcpupinInfo (domain, maxinfo,
+        ret = conn->driver->domainGetVcpupinInfo (domain, ncpumaps,
                                                   cpumaps, maplen, flags);
         if (ret < 0)
             goto error;
@@ -7197,6 +7192,9 @@ error:
  * Extract information about virtual CPUs of domain, store it in info array
  * and also in cpumaps if this pointer isn't NULL.
  *
+ * See also virDomainGetVcpupinInfo for querying just cpumaps, including on
+ * an inactive domain.
+ *
  * Returns the number of info filled in case of success, -1 in case of
failure.
  */
 int
diff --git i/src/libvirt_public.syms w/src/libvirt_public.syms
index 38e8446..c7dc3c5 100644
--- i/src/libvirt_public.syms
+++ w/src/libvirt_public.syms
@@ -453,6 +453,7 @@ LIBVIRT_0.9.2 {
 LIBVIRT_0.9.3 {
     global:
         virDomainGetControlInfo;
+        virDomainGetVcpupinInfo;
         virDomainPinVcpuFlags;
         virDomainSendKey;
         virEventAddHandle;
@@ -463,7 +464,6 @@ LIBVIRT_0.9.3 {
         virEventUpdateTimeout;
         virNodeGetCPUStats;
         virNodeGetMemoryStats;
-        virDomainGetVcpupinInfo;
 } LIBVIRT_0.9.2;

 # .... define new API here using predicted next version number ....


-- 
Eric Blake   eblake redhat com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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