Firstly, the virProcessGetStatInfo() does not fail really. But even if it did, it sets correct errno only sometimes (and even that is done in a helper it's calling - virProcessGetStat() and even there it's the case only in very few error paths). Therefore, using virReportSystemError() to report errors is very misleading. Use plain virReportError() instead. Luckily, there are only two places where the former was used: chDomainHelperGetVcpus() and qemuDomainHelperGetVcpus() (not a big surprise since CH driver is heavily inspired by QEMU driver). Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/ch/ch_driver.c | 4 ++-- src/qemu/qemu_driver.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c index db2a66d131..12fbe31c24 100644 --- a/src/ch/ch_driver.c +++ b/src/ch/ch_driver.c @@ -1079,8 +1079,8 @@ chDomainHelperGetVcpus(virDomainObj *vm, NULL, NULL, &vcpuinfo->cpu, NULL, vm->pid, vcpupid) < 0) { - virReportSystemError(errno, "%s", - _("cannot get vCPU placement & pCPU time")); + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("cannot get vCPU placement & pCPU time")); return -1; } } diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index d6879175fe..c576c601ad 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -1355,8 +1355,8 @@ qemuDomainHelperGetVcpus(virDomainObj *vm, NULL, NULL, &vcpuinfo->cpu, NULL, vm->pid, vcpupid) < 0) { - virReportSystemError(errno, "%s", - _("cannot get vCPU placement & pCPU time")); + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("cannot get vCPU placement & pCPU time")); return -1; } } -- 2.38.2

Yeah, we've already seen this commit (v8.0.0-rc2~4) and also its revert (v8.1.0-rc1~345). While the original idea was sound, the implementation was less so and it changed behaviour of some public APIs (e.g. whilst getting stats for a running guest was best effort it started to return errors). Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_driver.c | 11 ++++------- src/util/virprocess.c | 28 +++++++--------------------- 2 files changed, 11 insertions(+), 28 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index c576c601ad..25c681bfd2 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -2508,13 +2508,10 @@ qemuDomainGetInfo(virDomainPtr dom, } if (virDomainObjIsActive(vm)) { - if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL, - NULL, NULL, - vm->pid, 0) < 0) { - virReportError(VIR_ERR_OPERATION_FAILED, "%s", - _("cannot read cputime for domain")); - goto cleanup; - } + /* Specifically ignore the error here. QEMU's PID might be already gone + * even though the check above says it's still active. */ + virProcessGetStatInfo(&(info->cpuTime), NULL, + NULL, NULL, NULL, vm->pid, 0); } if (VIR_ASSIGN_IS_OVERFLOW(info->nrVirtCpu, virDomainDefGetVcpus(vm->def))) { diff --git a/src/util/virprocess.c b/src/util/virprocess.c index 39ca5de811..800af29537 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -1761,7 +1761,7 @@ virProcessGetStatInfo(unsigned long long *cpuTime, virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &stime) < 0 || virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 || virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) { - VIR_WARN("cannot parse process status data"); + return -1; } utime *= jiff2nsec; @@ -1778,7 +1778,6 @@ virProcessGetStatInfo(unsigned long long *cpuTime, if (vm_rss) *vm_rss = rss * virGetSystemPageSizeKB(); - VIR_DEBUG("Got status for %d/%d user=%llu sys=%llu cpu=%d rss=%ld", (int) pid, tid, utime, stime, cpu, rss); @@ -1852,28 +1851,15 @@ virProcessGetSchedInfo(unsigned long long *cpuWait, #else int -virProcessGetStatInfo(unsigned long long *cpuTime, - unsigned long long *userTime, - unsigned long long *sysTime, - int *lastCpu, - long *vm_rss, +virProcessGetStatInfo(unsigned long long *cpuTime G_GNUC_UNUSED, + unsigned long long *userTime G_GNUC_UNUSED, + unsigned long long *sysTime G_GNUC_UNUSED, + int *lastCpu G_GNUC_UNUSED, + long *vm_rss G_GNUC_UNUSED, pid_t pid G_GNUC_UNUSED, pid_t tid G_GNUC_UNUSED) { - /* We don't have a way to collect this information on non-Linux - * platforms, so just report neutral values */ - if (cpuTime) - *cpuTime = 0; - if (userTime) - *userTime = 0; - if (sysTime) - *sysTime = 0; - if (lastCpu) - *lastCpu = 0; - if (vm_rss) - *vm_rss = 0; - - return 0; + return -1; } int -- 2.38.2

On Wed, Jan 18, 2023 at 10:58:19AM +0100, Michal Privoznik wrote: The only thing I do not like about this patch is that we would now have both: static int qemuDomainGetCPUStatsProc(virDomainObj *vm, virTypedParameterPtr params, unsigned int nparams) and: static int qemuDomainGetStatsCpuProc(virDomainObj *vm, virTypedParamList *params) doing almost, but not completely, the same thing. And there is no nice way to avoid it. I just haven't noticed in v1, sorry. Or is there a way to converge at least some of these?

On Mon, Jan 23, 2023 at 02:12:06PM +0100, Michal Prívozník wrote: As I said I think there is no nice way to avoid it. Even if we figure out something there is no need to hold this back just for a few lines. Reviewed-by: Martin Kletzander <mkletzan(a)redhat.com&gt;