[pve-devel] applied: [PATCH pve-common v2] systemd: disconnect signals
Wolfgang Bumiller
w.bumiller at proxmox.com
Fri Mar 7 09:28:42 CET 2025
applied, with a minor cleanup
On Fri, Mar 07, 2025 at 09:14:14AM +0100, Maximiliano Sandoval wrote:
> Dbus has a limit of 512 connections by default and signals should be
> disconnected as soon as they are not needed anymore.
>
> This should alleviate https://bugzilla.proxmox.com/show_bug.cgi?id=5876.
>
> Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
> ---
>
> Differences from v1:
> - remove two guards on finish_callback
>
> src/PVE/Systemd.pm | 30 ++++++++++++++++++++++++------
> 1 file changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/src/PVE/Systemd.pm b/src/PVE/Systemd.pm
> index 07c912e3..14038e0c 100644
> --- a/src/PVE/Systemd.pm
> +++ b/src/PVE/Systemd.pm
> @@ -44,6 +44,7 @@ sub unescape_unit {
> # main loop is being used as we need to wait signals.
> sub systemd_call($;$) {
> my ($code, $timeout) = @_;
> + my $signal_info;
^ moved this down to the rest of the vars shared with the callback
>
> my $bus = Net::DBus->system();
> my $reactor = Net::DBus::Reactor->main();
> @@ -64,13 +65,18 @@ sub systemd_call($;$) {
> $timer = undef;
> }
>
> + if (defined($signal_info)) {
> + $if->disconnect_from_signal($signal_info->{name}, $signal_info->{handle});
> + $signal_info = undef;
> + }
> +
> if (defined($reactor)) {
> $reactor->shutdown();
> $reactor = undef;
> }
> };
>
> - my $result = $code->($if, $reactor, $finish_callback);
> + (my $result, $signal_info) = $code->($if, $reactor, $finish_callback);
> # Are we done immediately?
> return $result if defined $result;
>
> @@ -124,7 +130,8 @@ sub enter_systemd_scope {
>
> my $job;
>
> - $if->connect_to_signal('JobRemoved', sub {
> + my $signal_name = 'JobRemoved';
> + my $signal_handle = $if->connect_to_signal($signal_name, sub {
> my ($id, $removed_job, $signaled_unit, $result) = @_;
> return if $signaled_unit ne $unit || $removed_job ne $job;
> if ($result ne 'done') {
> @@ -139,7 +146,12 @@ sub enter_systemd_scope {
>
> $job = $if->StartTransientUnit($unit, 'fail', $properties, []);
>
> - return undef;
> + my $signal_info = {
> + name => $signal_name,
> + handle => $signal_handle,
> + };
> +
> + return (undef, $signal_info);
> }, $timeout);
> }
>
> @@ -152,18 +164,24 @@ sub wait_for_unit_removed($;$) {
> my $unit_obj = eval { $if->GetUnit($unit) };
> return 1 if !$unit_obj;
>
> - $if->connect_to_signal('UnitRemoved', sub {
> + my $signal_name = 'UnitRemoved';
> + my $signal_handle = $if->connect_to_signal($signal_name, sub {
> my ($id, $removed_unit) = @_;
> $finish_cb->(1) if $removed_unit eq $unit_obj;
> });
>
> + my $signal_info = {
> + name => $signal_name,
> + handle => $signal_handle,
> + };
> +
> # Deal with what we lost between GetUnit() and connecting to UnitRemoved:
> my $unit_obj_new = eval { $if->GetUnit($unit) };
> if (!$unit_obj_new) {
> - return 1;
> + return (1, $signal_info);
> }
>
> - return undef;
> + return (undef, $signal_info);
> }, $timeout);
> }
>
> --
> 2.39.5
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