Implement public API for virDomainGetIOThreadsInfo

Add virDomainGetIOThreadInfo in order to return a list of
virDomainIOThreadInfoPtr structures which list the IOThread ID
and the CPU Affinity map for each IOThread for the domain.

For an active domain, the live data will be returned, while for
an inactive domain, the config data will be returned.

The API supports either the --live or --config flag, but not both.

Also added virDomainIOThreadsInfoFree in order to free the cpumap
and the IOThreadInfo structure.

Signed-off-by: John Ferlan <jferlan@redhat.com>

include/libvirt/libvirt-domain.h

@@ -4,7 +4,7 @@
  * Description: Provides APIs for the management of domains
  * Author: Daniel Veillard <veillard@redhat.com>
  *
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -1590,6 +1590,26 @@ int                     virDomainGetEmulatorPinInfo (virDomainPtr domain,
                                                      int maplen,
                                                      unsigned int flags);
 
+/**
+ * virIOThreadInfo:
+ *
+ * The data structure for information about all IOThreads in a domain
+ */
+typedef struct _virDomainIOThreadInfo virDomainIOThreadInfo;
+typedef virDomainIOThreadInfo *virDomainIOThreadInfoPtr;
+struct _virDomainIOThreadInfo {
+    unsigned int iothread_id;          /* IOThread ID */
+    unsigned char *cpumap;             /* CPU map for thread. A pointer to an */
+                                       /* array of real CPUs (in 8-bit bytes) */
+    int cpumaplen;                     /* cpumap size */
+};
+
+void                 virDomainIOThreadsInfoFree(virDomainIOThreadInfoPtr info);
+
+int                  virDomainGetIOThreadsInfo(virDomainPtr domain,
+                                               virDomainIOThreadInfoPtr **info,
+                                               unsigned int flags);
+
 /**
  * VIR_USE_CPU:
  * @cpumap: pointer to a bit map of real CPUs (in 8-bit bytes) (IN/OUT)

src/driver-hypervisor.h

@@ -1,7 +1,7 @@
 /*
  * driver-hypervisor.h: entry points for hypervisor drivers
  *
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -380,6 +380,11 @@ typedef int
 typedef int
 (*virDrvDomainGetMaxVcpus)(virDomainPtr domain);
 
+typedef int
+(*virDrvDomainGetIOThreadsInfo)(virDomainPtr domain,
+                                virDomainIOThreadInfoPtr **info,
+                                unsigned int flags);
+
 typedef int
 (*virDrvDomainGetSecurityLabel)(virDomainPtr domain,
                                 virSecurityLabelPtr seclabel);
@@ -1254,6 +1259,7 @@ struct _virHypervisorDriver {
     virDrvDomainGetEmulatorPinInfo domainGetEmulatorPinInfo;
     virDrvDomainGetVcpus domainGetVcpus;
     virDrvDomainGetMaxVcpus domainGetMaxVcpus;
+    virDrvDomainGetIOThreadsInfo domainGetIOThreadsInfo;
     virDrvDomainGetSecurityLabel domainGetSecurityLabel;
     virDrvDomainGetSecurityLabelList domainGetSecurityLabelList;
     virDrvNodeGetSecurityModel nodeGetSecurityModel;

src/libvirt-domain.c

@@ -1,7 +1,7 @@
 /*
  * libvirt-domain.c: entry points for virDomainPtr APIs
  *
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -7893,6 +7893,79 @@ virDomainGetMaxVcpus(virDomainPtr domain)
 }
 
 
+/**
+ * virDomainGetIOThreadsInfo:
+ * @dom: a domain object
+ * @info: pointer to an array of virDomainIOThreadInfo structures (OUT)
+ * @flags: bitwise-OR of virDomainModificationImpact
+ *     Must not be VIR_DOMAIN_AFFECT_LIVE and
+ *     VIR_DOMAIN_AFFECT_CONFIG concurrently.
+ *
+ * Fetch IOThreads of an active domain including the cpumap information to
+ * determine on which CPU the IOThread has affinity to run.
+ *
+ * Returns the number of IOThreads or -1 in case of error.
+ * On success, the array of information is stored into @info. The caller is
+ * responsible for calling virDomainIOThreadsInfoFree() on each array element,
+ * then calling free() on @info. On error, @info is set to NULL.
+ */
+int
+virDomainGetIOThreadsInfo(virDomainPtr dom,
+                          virDomainIOThreadInfoPtr **info,
+                          unsigned int flags)
+{
+    VIR_DOMAIN_DEBUG(dom, "info=%p flags=%x", info, flags);
+
+    virResetLastError();
+
+    virCheckDomainReturn(dom, -1);
+    virCheckReadOnlyGoto(dom->conn->flags, error);
+    virCheckNonNullArgGoto(info, error);
+    *info = NULL;
+
+    /* At most one of these two flags should be set.  */
+    if ((flags & VIR_DOMAIN_AFFECT_LIVE) &&
+        (flags & VIR_DOMAIN_AFFECT_CONFIG)) {
+        virReportInvalidArg(flags,
+                            _("flags 'affect live' and 'affect config' in %s "
+                              "are mutually exclusive"),
+                            __FUNCTION__);
+        goto error;
+    }
+
+    if (dom->conn->driver->domainGetIOThreadsInfo) {
+        int ret;
+        ret = dom->conn->driver->domainGetIOThreadsInfo(dom, info, flags);
+        if (ret < 0)
+            goto error;
+        return ret;
+    }
+
+    virReportUnsupportedError();
+
+ error:
+    virDispatchError(dom->conn);
+    return -1;
+}
+
+
+/**
+ * virDomainIOThreadsInfoFree:
+ * @info: pointer to a virDomainIOThreadInfo object
+ *
+ * Frees the memory used by @info.
+ */
+void
+virDomainIOThreadsInfoFree(virDomainIOThreadInfoPtr info)
+{
+    if (!info)
+        return;
+
+    VIR_FREE(info->cpumap);
+    VIR_FREE(info);
+}
+
+
 /**
  * virDomainGetSecurityLabel:
  * @domain: a domain object

src/libvirt_public.syms

@@ -695,4 +695,10 @@ LIBVIRT_1.2.12 {
         virDomainDefineXMLFlags;
 } LIBVIRT_1.2.11;
 
+LIBVIRT_1.2.14 {
+    global:
+        virDomainIOThreadsInfoFree;
+        virDomainGetIOThreadsInfo;
+} LIBVIRT_1.2.12;
+
 # .... define new API here using predicted next version number ....