cgroup: add get_io_stats and parse_nested_keyed_file

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

diff --git a/src/PVE/LXC/CGroup.pm b/src/PVE/LXC/CGroup.pm
index 7561fb2d69a17358d57800c17c96ca30b9ff671f..207c0c1865b56a790b8d31cb421a1b9ab8ea787e 100644 (file)
--- a/src/PVE/LXC/CGroup.pm
+++ b/src/PVE/LXC/CGroup.pm
@@ -12,6 +12,11 @@ package PVE::LXC::CGroup;
 use strict;
 use warnings;
 
+use PVE::Tools qw(
+    file_get_contents
+    file_read_firstline
+);
+
 use PVE::LXC::Command;
 
 # We don't want to do a command socket round trip for every cgroup read/write,
@@ -125,4 +130,70 @@ sub get_path {
     return "/sys/fs/cgroup/$controller/$path";
 }
 
+# Parse a 'Nested keyed' file:
+#
+# See kernel documentation `admin-guide/cgroup-v2.rst` 4.1.
+my sub parse_nested_keyed_file($) {
+    my ($data) = @_;
+    my $res = {};
+    foreach my $line (split(/\n/, $data)) {
+       my ($key, @values) = split(/\s+/, $line);
+
+       my $d = ($res->{$key} = {});
+
+       foreach my $value (@values) {
+           if (my ($key, $value) = ($value =~ /^([^=]+)=(.*)$/)) {
+               $d->{$key} = $value;
+           } else {
+               warn "bad key=value pair in nested keyed file\n";
+           }
+       }
+    }
+}
+
+# Get I/O stats for a container.
+sub get_io_stats {
+    my ($self) = @_;
+
+    my $res = {
+       diskread => 0,
+       diskwrite => 0,
+    };
+
+    if (cgroup_mode() == 2) {
+       if (defined(my $path = $self->get_path('io'))) {
+           # cgroupv2 environment, io controller enabled
+           my $io_stat = file_get_contents("$path/io.stat");
+
+           my $data = parse_nested_keyed_file($io_stat);
+           foreach my $dev (keys %$data) {
+               my $dev = $data->{$dev};
+               if (my $b = $dev->{rbytes}) {
+                   $res->{diskread} += $b;
+               }
+               if (my $b = $dev->{wbytes}) {
+                   $res->{diskread} += $b;
+               }
+           }
+       } else {
+           # io controller not enabled or container not running
+           return undef;
+       }
+    } elsif (defined(my $path = $self->get_path('blkio'))) {
+       # cgroupv1 environment:
+       my $io = file_get_contents("$path/blkio.throttle.io_service_bytes_recursive");
+       foreach my $line (split(/\n/, $io)) {
+           if (my ($type, $bytes) = ($line =~ /^\d+:\d+\s+(Read|Write)\s+(\d+)$/)) {
+               $res->{diskread} += $bytes if $type eq 'Read';
+               $res->{diskwrite} += $bytes if $type eq 'Write';
+           }
+       }
+    } else {
+       # container not running
+       return undef;
+    }
+
+    return $res;
+}
+
 1;