Re: [libvirt] [PATCHv5 14/19] Util: Add function for checking if monitor is running

-----Original Message----- From: John Ferlan [mailto:jferlan@redhat.com] Sent: Thursday, October 11, 2018 4:58 AM To: Wang, Huaqiang <huaqiang.wang(a)intel.com>; libvir-list(a)redhat.com Cc: Feng, Shaohe <shaohe.feng(a)intel.com>; Niu, Bing <bing.niu(a)intel.com>; Ding, Jian-feng <jian-feng.ding(a)intel.com>; Zang, Rui <rui.zang(a)intel.com&gt; Subject: Re: [libvirt] [PATCHv5 14/19] Util: Add function for checking if monitor is running On 10/9/18 6:30 AM, Wang Huaqiang wrote: > Check monitor status by checking the PIDs are in file 'task' > or not. > > Signed-off-by: Wang Huaqiang <huaqiang.wang(a)intel.com&gt; > --- > src/libvirt_private.syms | 1 + > src/util/virresctrl.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++- > src/util/virresctrl.h | 4 +++ > 3 files changed, 88 insertions(+), 1 deletion(-) > > diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index > 4b22ed4..c90e48a 100644 > --- a/src/libvirt_private.syms > +++ b/src/libvirt_private.syms > @@ -2686,6 +2686,7 @@ virResctrlMonitorDeterminePath; > virResctrlMonitorGetCacheLevel; virResctrlMonitorGetCacheOccupancy; > virResctrlMonitorGetID; > +virResctrlMonitorIsRunning; > virResctrlMonitorNew; > virResctrlMonitorRemove; > virResctrlMonitorSetCacheLevel; > diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c index > 41e8d48..67dfbb8 100644 > --- a/src/util/virresctrl.c > +++ b/src/util/virresctrl.c > @@ -364,6 +364,9 @@ struct _virResctrlMonitor { > char *path; > /* Boolean flag for default monitor */ > bool default_monitor; > + /* Tracking the tasks' PID associated with this monitor */ > + pid_t *pids; > + size_t npids; > /* The cache 'level', special for cache monitor */ > unsigned int cache_level; > }; > @@ -425,6 +428,7 @@ virResctrlMonitorDispose(void *obj) > virObjectUnref(monitor->alloc); > VIR_FREE(monitor->id); > VIR_FREE(monitor->path); > + VIR_FREE(monitor->pids); > } > > > @@ -2491,7 +2495,13 @@ int > virResctrlMonitorAddPID(virResctrlMonitorPtr monitor, > pid_t pid) > { > - return virResctrlAddPID(monitor->path, pid); > + if (virResctrlAddPID(monitor->path, pid) < 0) > + return -1; > + > + if (VIR_APPEND_ELEMENT(monitor->pids, monitor->npids, pid) < 0) > + return -1; > + > + return 0; > } > > > @@ -2762,3 +2772,75 @@ > virResctrlMonitorSetDefault(virResctrlMonitorPtr monitor) { > monitor->default_monitor = true; > } > + > + > +static int > +virResctrlPIDCompare(const void *pida, const void *pidb) { > + return *(pid_t*)pida - *(pid_t*)pidb; } > + > + > +bool > +virResctrlMonitorIsRunning(virResctrlMonitorPtr monitor) { > + char *pidstr = NULL; > + char **spids = NULL; > + size_t nspids = 0; > + pid_t *pids = NULL; > + size_t npids = 0; > + size_t i = 0; > + int rv = -1; > + bool ret = false; > + > + if (!monitor->path) > + return false; > + > + if (monitor->npids == 0) > + return false; > + > + rv = virFileReadValueString(&pidstr, "%s/tasks", monitor->path); > + if (rv == -2) > + virReportError(VIR_ERR_INTERNAL_ERROR, > + _("Task file '%s/tasks' does not exist"), > + monitor->path); > + if (rv < 0) > + goto cleanup; > + > + /* no PID in task file */ > + if (!*pidstr) > + goto cleanup; > + > + spids = virStringSplitCount(pidstr, "\n", 0, &nspids); > + if (nspids != monitor->npids) > + return false; This will cause a leak... "goto cleanup;"

> + > + for (i = 0; i < nspids; i++) { > + unsigned int val = 0; > + pid_t pid = 0; > + > + if (virStrToLong_uip(spids[i], NULL, 0, &val) < 0) > + goto cleanup; > + > + pid = (pid_t)val; > + > + if (VIR_APPEND_ELEMENT(pids, npids, pid) < 0) > + goto cleanup; > + } > + > + qsort(pids, npids, sizeof(pid_t), virResctrlPIDCompare); > + qsort(monitor->pids, monitor->npids, sizeof(pid_t), > + virResctrlPIDCompare); > + > + for (i = 0; i < monitor->npids; i++) { > + if (monitor->pids[i] != pids[i]) > + goto cleanup; > + } > + > + ret = true; > + cleanup: NB: Any place where you get here without an error message, but w/ ret = false may cause "issues" for the caller especially since some of the ways to get here w/ @false do set an error message.

John

> + virStringListFree(spids); > + VIR_FREE(pids); > + VIR_FREE(pidstr); > + > + return ret; > +} > diff --git a/src/util/virresctrl.h b/src/util/virresctrl.h index > 371df8a..c5794cb 100644 > --- a/src/util/virresctrl.h > +++ b/src/util/virresctrl.h > @@ -230,4 +230,8 @@ virResctrlMonitorGetCacheOccupancy(virResctrlMonitorPtr monitor, > unsigned int **bankcaches); void > virResctrlMonitorSetDefault(virResctrlMonitorPtr monitor); > + > +bool > +virResctrlMonitorIsRunning(virResctrlMonitorPtr monitor); > + > #endif /* __VIR_RESCTRL_H__ */ >