ch_monitor: Move the thread tracking to monitor object.

Now that we have a monitor notification from cloud-hypervisor,
it makes sense to move the thread tracking to monitor. Later
patches will add support for using the monitor framework from
cloud-hypervisor.

Signed-off-by: Vineeth Pillai <[email protected]>

Author: Vineeth Pillai

src/ch/ch_monitor.c

@@ -28,6 +28,7 @@
 #include "ch_conf.h"
 #include "ch_domain.h"
 #include "ch_monitor.h"
+#include "ch_process.h"
 #include "viralloc.h"
 #include "vircommand.h"
 #include "virerror.h"
@@ -562,6 +563,61 @@ chMonitorBuildSocketCmd(virDomainObjPtr vm, const char *socket_path)
     return cmd;
 }
 
+static void virCHMonitorEventLoop(void *data)
+{
+    virCHMonitorPtr mon = (virCHMonitorPtr)data;
+    virDomainObjPtr vm = mon->vm;
+
+    VIR_DEBUG("Monitor event loop thread starting");
+
+    virObjectRef(vm);
+    while (g_atomic_int_get(&mon->event_loop_stop) == 0) {
+
+        g_usleep(G_USEC_PER_SEC);
+
+        virObjectLock(vm);
+        if (virDomainObjIsActive(vm) &&
+            virCHDomainObjBeginJob(vm, CH_JOB_MODIFY) == 0) {
+            virCHProcessSetupThreads(vm);
+            virCHDomainObjEndJob(vm);
+        }
+        virObjectUnlock(vm);
+    }
+    virObjectUnref(vm);
+
+    VIR_DEBUG("Monitor event loop thread exiting");
+
+    virObjectUnref(mon);
+    return;
+}
+
+static int virCHMonitorStartEventLoop(virCHMonitorPtr mon)
+{
+    g_autofree char *name = NULL;
+
+    name = g_strdup_printf("mon-events-%d", mon->pid);
+
+    virObjectRef(mon);
+    if (virThreadCreateFull(&mon->event_loop_thread,
+                            false,
+                            virCHMonitorEventLoop,
+                            name,
+                            false,
+                            mon) < 0) {
+        virObjectUnref(mon);
+        return -1;
+
+    }
+
+    g_atomic_int_set(&mon->event_loop_stop, 0);
+    return 0;
+}
+
+static void virCHMonitorStopEventLoop(virCHMonitorPtr mon)
+{
+    g_atomic_int_set(&mon->event_loop_stop, 1);
+}
+
 virCHMonitorPtr
 virCHMonitorOpen(virDomainObjPtr vm, virCHDriverPtr driver)
 {
@@ -698,6 +754,10 @@ virCHMonitorNew(virDomainObjPtr vm, virCHDriverPtr driver)
     if (virDomainObjSave(vm, driver->xmlopt, cfg->stateDir) < 0)
         goto cleanup;
 
+    if (virCHMonitorStartEventLoop(mon) < 0) {
+        goto cleanup;
+    }
+
     /* now has its own reference */
     virObjectRef(mon);
     mon->vm = virObjectRef(vm);
@@ -744,6 +804,8 @@ void virCHMonitorClose(virCHMonitorPtr mon)
         close(mon->monitor_fd);
     }
 
+    virCHMonitorStopEventLoop(mon);
+
     virObjectUnref(mon);
     if (mon->vm)
         virObjectUnref(mon->vm);
@@ -1109,10 +1171,14 @@ virCHMonitorRefreshThreadInfo(virCHMonitorPtr mon)
 {
     virCHMonitorThreadInfoPtr info = NULL;
     g_autofree pid_t *tids = NULL;
-    virDomainObjPtr vm = mon->vm;
+    virDomainObjPtr vm;
     size_t ntids = 0;
     size_t i;
 
+    if (!mon)
+        return -1;
+
+    vm = mon->vm;
     if (virProcessGetPids(vm->pid, &ntids, &tids) < 0) {
         virCHMonitorThreadInfoFree(mon);
         return -1;

src/ch/ch_monitor.h

@@ -96,6 +96,8 @@ struct _virCHMonitor {
     char *socketpath;
 
     int monitor_fd;
+    virThread event_loop_thread;
+    int event_loop_stop;
 
     pid_t pid;
 

src/ch/ch_process.c

@@ -508,7 +508,7 @@ virCHProcessSetupVcpus(virDomainObjPtr vm)
     return 0;
 }
 
-static int virCHProcessSetupThreads(virDomainObjPtr vm)
+int virCHProcessSetupThreads(virDomainObjPtr vm)
 {
     virCHDomainObjPrivatePtr priv = vm->privateData;
     int ret;
@@ -533,87 +533,6 @@ static int virCHProcessSetupThreads(virDomainObjPtr vm)
     return ret;
 }
 
-/*
- * Procfs Thread watcher
- * This thread is started when a Domain boots up and
- * exists as long as the domain is active. The duty
- * of the thread is to watch for any tid changes for
- * the VM and then update the cgroups accordingly.
- * Threads can change in the case of following events:
- * - VM reboot
- * - Device activation
- *
- * TODO: Parsing procfs frequently is ugly and not scalable
- *       Better option would be to have cloud-hypervisor
- *       return the thread information via API query or
- *       probably to have a monitor interface like what
- *       qemu has.
- */
-
-/*
- * Hard coding the polling interval for the watcher thread
- * to be 1 second.
- */
-#define THREAD_WATCHER_POLL_INTERVAL    G_USEC_PER_SEC
-
-static void chProcessWatchThreads(void *data)
-{
-    virDomainObjPtr vm = (virDomainObjPtr)data;
-    virCHDomainObjPrivatePtr priv;
-
-    VIR_DEBUG("VM Thread watcher starting");
-
-    virObjectLock(vm);
-    priv = vm->privateData;
-    while (g_atomic_int_get(&priv->vmThreadWatcherStop) == 0 &&
-           virDomainObjIsActive(vm)) {
-
-        if (virCHDomainObjBeginJob(vm, CH_JOB_MODIFY) < 0) {
-            VIR_WARN("VRP: Failed to Lock vm state");
-        } else {
-            virCHProcessSetupThreads(vm);
-            virCHDomainObjEndJob(vm);
-        }
-
-        virObjectUnlock(vm);
-        g_usleep(G_USEC_PER_SEC);
-        virObjectLock(vm);
-    }
-    VIR_DEBUG("VM Thread watcher exiting");
-
-    virDomainObjEndAPI(&vm);
-    return;
-}
-
-static int virCHProcessStartWatchThreads(virDomainObjPtr vm)
-{
-    virCHDomainObjPrivatePtr priv = vm->privateData;
-    g_autofree char *name = NULL;
-
-    name = g_strdup_printf("threadwatcher-%d", vm->pid);
-
-    virObjectRef(vm);
-    if (virThreadCreateFull(&priv->vmThreadWatcher,
-                            false,
-                            chProcessWatchThreads,
-                            name,
-                            false,
-                            vm) < 0) {
-        virObjectUnref(vm);
-        return -1;
-
-    }
-
-    g_atomic_int_set(&priv->vmThreadWatcherStop, 0);
-    return 0;
-}
-
-static void virCHProcessStopWatchThreads(virDomainObjPtr vm)
-{
-    virCHDomainObjPrivatePtr priv = vm->privateData;
-    g_atomic_int_set(&priv->vmThreadWatcherStop, 1);
-}
-
 /**
  * chProcessNetworkPrepareDevices
  */
@@ -776,10 +695,6 @@ int virCHProcessStart(virCHDriverPtr driver,
     if (chSetupGlobalCpuCgroup(vm) < 0)
         goto cleanup;
 
-    VIR_DEBUG("Starting the thread watcher thread");
-    if (virCHProcessStartWatchThreads(vm) < 0)
-        goto cleanup;
-
     virDomainObjSetState(vm, VIR_DOMAIN_RUNNING, reason);
 
     if (virDomainObjSave(vm, driver->xmlopt, cfg->stateDir) < 0)
@@ -1036,8 +951,6 @@ int virCHProcessStop(virCHDriverPtr driver,
     VIR_DEBUG("Stopping VM name=%s pid=%d reason=%d",
               vm->def->name, (int)vm->pid, (int)reason);
 
-    virCHProcessStopWatchThreads(vm);
-
     if (priv->monitor) {
         virCHMonitorClose(priv->monitor);
         priv->monitor = NULL;

src/ch/ch_process.h

@@ -29,6 +29,8 @@ int virCHProcessStop(virCHDriverPtr driver,
                      virDomainObjPtr vm,
                      virDomainShutoffReason reason);
 
+int virCHProcessSetupThreads(virDomainObjPtr vm);
+
 int virCHProcessSetupVcpu(virDomainObjPtr vm,
                           unsigned int vcpuid);