Re: [libvirt] [PATCH] Debug: Record the VM PID in per-VM logs.

[Ján Tomko]

On Sun, Jul 17, 2016 at 11:17:01PM -0700, Prerna Saxena wrote:

For certain situations such as Out-of-memory scenarios, it is helpful to
record the QEMU PID in the per-VM logs, so that correlation with kernel-reported
events is easier.

While this is already recorded in libvirt daemon logs as a DEBUG message,
I believe it merits more attention :-)
Hence introducing it in per-VM log.

Signed-off-by: Prerna Saxena 
---
src/qemu/qemu_process.c | 7 +++
1 file changed, 7 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 4adb14e..2d3b0f5 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4983,6 +4983,7 @@ qemuProcessLaunch(virConnectPtr conn,
int ret = -1;
int rv;
int logfile = -1;
+char *msg_buffer = NULL;
qemuDomainLogContextPtr logCtxt = NULL;
qemuDomainObjPrivatePtr priv = vm->privateData;
virCommandPtr cmd = NULL;
@@ -5095,8 +5096,14 @@ qemuProcessLaunch(virConnectPtr conn,
   _("Domain %s didn't show up"), vm->def->name);
rv = -1;
}
+
VIR_DEBUG("QEMU vm=%p name=%s running with pid=%llu",
  vm, vm->def->name, (unsigned long long)vm->pid);
+ignore_value(virAsprintf(_buffer,
+"QEMU vm=%p name=%s running with pid=%llu",
+vm, vm->def->name, (unsigned long long)vm->pid));
+qemuLogOperation(vm, msg_buffer, NULL, logCtxt);


I don't think we need to log the qemu version and hostname again.
We don't do that on shutdown either.

qemuDomainLogContextWrite should be enough.

Also, logging a pointer seems pointless, and so does logging the vm
name (which should be in the filename).


+virFree(msg_buffer);


'make syntax-check' complains:

src/qemu/qemu_process.c:5106:virFree(msg_buffer);
maint.mk: use VIR_ macros instead of internal functions
cfg.mk:321: recipe for target 'sc_prohibit_internal_functions' failed

Jan

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[libvirt] [PATCH] Debug: Record the VM PID in per-VM logs.

[Prerna Saxena]

For certain situations such as Out-of-memory scenarios, it is helpful to
record the QEMU PID in the per-VM logs, so that correlation with kernel-reported
events is easier.

While this is already recorded in libvirt daemon logs as a DEBUG message,
I believe it merits more attention :-)
Hence introducing it in per-VM log.

Signed-off-by: Prerna Saxena 
---
 src/qemu/qemu_process.c | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 4adb14e..2d3b0f5 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4983,6 +4983,7 @@ qemuProcessLaunch(virConnectPtr conn,
 int ret = -1;
 int rv;
 int logfile = -1;
+char *msg_buffer = NULL;
 qemuDomainLogContextPtr logCtxt = NULL;
 qemuDomainObjPrivatePtr priv = vm->privateData;
 virCommandPtr cmd = NULL;
@@ -5095,8 +5096,14 @@ qemuProcessLaunch(virConnectPtr conn,
_("Domain %s didn't show up"), vm->def->name);
 rv = -1;
 }
+
 VIR_DEBUG("QEMU vm=%p name=%s running with pid=%llu",
   vm, vm->def->name, (unsigned long long)vm->pid);
+ignore_value(virAsprintf(_buffer,
+"QEMU vm=%p name=%s running with pid=%llu",
+vm, vm->def->name, (unsigned long long)vm->pid));
+qemuLogOperation(vm, msg_buffer, NULL, logCtxt);
+virFree(msg_buffer);
 } else {
 VIR_DEBUG("QEMU vm=%p name=%s failed to spawn",
   vm, vm->def->name);
-- 
1.8.1.2

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