[pve-devel] [PATCH v2 manager 01/12] Broadcast supported CPU flags

[Stefan Reiter]

pvestatd will check if the KVM version has changed using
kvm_user_version (which automatically clears its cache if QEMU/KVM
updates), and if it has, query supported CPU flags and broadcast them as
a key-value pair to the cluster.

Detects value regressions and handles them gracefully (i.e. if
query_supported_cpu_flags fails, we try to retain the previously
detected flags).

Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---

v1 -> v2:
* broadcast directly in update_supported_cpuflags
* use kvm_user_version to determine when to re-query CPU flags
* don't broadcast flags when unchanged or empty


 PVE/Service/pvestatd.pm | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/PVE/Service/pvestatd.pm b/PVE/Service/pvestatd.pm
index bad1b73d..5ac97c98 100755
--- a/PVE/Service/pvestatd.pm
+++ b/PVE/Service/pvestatd.pm
@@ -78,6 +78,40 @@ sub hup {
     $restart_request = 1;
 }
 
+my $last_kvm_version = '';
+
+sub update_supported_cpuflags {
+    my $kvm_version = PVE::QemuServer::kvm_user_version();
+
+    # only update when QEMU/KVM version has changed, as that is the only reason
+    # why flags could change without restarting pvestatd
+    return if $last_kvm_version eq $kvm_version;
+    $last_kvm_version = $kvm_version;
+
+    my $supported_cpuflags;
+
+    eval {
+	$supported_cpuflags = join(" ", @{PVE::QemuServer::query_supported_cpu_flags()});
+    };
+    warn $@ if $@;
+
+    # detect regression
+    if (!$supported_cpuflags || $supported_cpuflags eq '') {
+	my $prev_cpuflags = PVE::Cluster::get_node_kv('cpuflags', $nodename)->{$nodename};
+	if ($prev_cpuflags && $prev_cpuflags ne '') {
+	    warn "CPU flag detection failed, using old values\n";
+	} else {
+	    warn "CPU flag detection failed and no previous values found\n";
+	}
+
+	# either flags are already in kv store, so no need to re-broadcast,
+	# or we don't have valid flags, and no point broadcasting empty string
+	return;
+    }
+
+    PVE::Cluster::broadcast_node_kv('cpuflags', $supported_cpuflags);
+}
+
 my $generate_rrd_string = sub {
     my ($data) = @_;
 
@@ -97,7 +131,9 @@ sub update_node_status {
 
     my $cpuinfo = PVE::ProcFSTools::read_cpuinfo();
 
-    my $maxcpu = $cpuinfo->{cpus}; 
+    my $maxcpu = $cpuinfo->{cpus};
+
+    update_supported_cpuflags();
 
     my $subinfo = PVE::INotify::read_file('subscription');
     my $sublevel = $subinfo->{level} || '';
@@ -110,7 +146,7 @@ sub update_node_status {
 	$netin += $netdev->{$dev}->{receive};
 	$netout += $netdev->{$dev}->{transmit};
     }
- 
+
     my $meminfo = PVE::ProcFSTools::read_meminfo();
 
     my $dinfo = df('/', 1);     # output is bytes
-- 
2.20.1