[PATCH v2 3/4] Register cpu hotplug netlink handler for qemu driver.

[Tang Chen <tangchen@xxxxxxxxxxxxxx>]

This patch sets cpuset.cpus to lastest for qemu driver when the driver
is being initialized, and then registers 2 cpu hotplug events handlers
for qemu driver:
    - qemuNetlinkCpuHotplugHandleCallback()
    - qemuNetlinkCpuHotplugRemoveCallback()

Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
---
 src/qemu/qemu_driver.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 53d6e5b..08f7be1 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -92,6 +92,9 @@
 #include "virnodesuspend.h"
 #include "virtime.h"
 #include "virtypedparam.h"
+#include "hotplug.h"
+#include "cgroup.h"
+#include "virnetlink.h"
 
 #define VIR_FROM_THIS VIR_FROM_QEMU
 
@@ -525,6 +528,43 @@ static void qemuDomainNetsRestart(void *payload,
     virDomainObjUnlock(vm);
 }
 
+static void
+qemuNetlinkCpuHotplugHandleCallback(unsigned char *msg,
+                                    int length,
+                                    struct sockaddr_nl *peer ATTRIBUTE_UNUSED,
+                                    bool *handled ATTRIBUTE_UNUSED,
+                                    void *opaque)
+{
+    virCgroupPtr cgroup = NULL;
+
+    /* opaque is a cgroup identifier pointing to libvirt root cgroup. */
+    if (!opaque) {
+        virReportSystemError(EINVAL,
+                             "%s",
+                             _("invalid argument"));
+        return;
+    }
+
+    cgroup = (virCgroupPtr)opaque;
+
+    if (virHotplugUpdateCgroupCpuset(msg, length, cgroup) < 0) {
+        virReportSystemError(errno,
+                             "%s",
+                             _("Unable to update cpuset in cgroup"));
+    }
+
+    return;
+}
+
+static void
+qemuNetlinkCpuHotplugRemoveCallback(int watch ATTRIBUTE_UNUSED,
+                                    const virMacAddrPtr macaddr ATTRIBUTE_UNUSED,
+                                    void *opaque ATTRIBUTE_UNUSED)
+{
+    /* For now, nothing to do. */
+    VIR_INFO("CPU hotplug netlink handler has been removed.");
+}
+
 /**
  * qemudStartup:
  *
@@ -682,6 +722,30 @@ qemudStartup(int privileged) {
                  virStrerror(-rc, ebuf, sizeof(ebuf)));
     }
 
+#if defined(__linux__) && defined(NETLINK_KOBJECT_UEVENT)
+    /**
+     * If we had ever missed any cpu hotplug event, we need to update
+     * cpuset.cpus to the lastest value
+     */
+    rc = virHotplugSetCpusetToLastest(qemu_driver->cgroup);
+    if (rc < 0) {
+        VIR_INFO("Unable to reset cgroup for driver: %s",
+                 virStrerror(-rc, ebuf, sizeof(ebuf)));
+    }
+
+    /* Register cpu hotplug event handler for qemu driver */
+    if (virNetlinkEventServiceIsRunning(NETLINK_KOBJECT_UEVENT)) {
+        rc = virNetlinkEventAddClient(qemuNetlinkCpuHotplugHandleCallback,
+                                      qemuNetlinkCpuHotplugRemoveCallback,
+                                      qemu_driver->cgroup, NULL,
+                                      NETLINK_KOBJECT_UEVENT);
+        if (rc < 0) {
+            VIR_INFO("Unable to register cpu hotplug event handler for driver: %s",
+                     virStrerror(-rc, ebuf, sizeof(ebuf)));
+        }
+    }
+#endif
+
     if (qemudLoadDriverConfig(qemu_driver, driverConf) < 0) {
         goto error;
     }
-- 
1.7.10.1

--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list