CpuSet: Simply class to handle cpu sets

src/Makefile

@@ -7,6 +7,7 @@ MAN1DIR=${MANDIR}/man1/
 PERLDIR=${PREFIX}/share/perl5
 
 LIB_SOURCES=			\
+	CpuSet.pm		\
 	Daemon.pm		\
 	SectionConfig.pm	\
 	Network.pm		\

src/PVE/CpuSet.pm

@@ -0,0 +1,139 @@
+package PVE::CpuSet;
+
+use strict;
+use warnings;
+use PVE::Tools;
+
+our $MAX_CPUID = 256; # should be enough for the next years
+
+sub new {
+    my ($this) = @_;
+
+    my $class = ref($this) || $this;
+
+    my $self = bless { members => {} }, $class;
+
+    return $self;
+}
+
+sub new_from_cgroup {
+    my ($this, $cgroup, $kind) = @_;
+
+    $kind //= 'cpus';
+
+    my $filename = "/sys/fs/cgroup/cpuset/$cgroup/cpuset.$kind";
+    my $set_text = PVE::Tools::file_read_firstline($filename) // '';
+
+    my $cpuset = $this->new();
+    
+    my $members = $cpuset->{members};
+
+    my $count = 0;
+
+    foreach my $part (split(/,/, $set_text)) {
+	if ($part =~ /^\s*(\d+)(?:-(\d+))?\s*$/) {
+	    my ($from, $to) = ($1, $2);
+	    $to //= $1;
+	    die "cpu id '$from' is out of range\n" if $from >= $MAX_CPUID;
+	    die "cpu id '$to' is out of range\n" if $to >= $MAX_CPUID;
+	    die "invalid range: $part ($to < $from)\n" if $to < $from;
+	    for (my $i = $from; $i <= $to; $i++) {
+		$members->{$i} = 1;
+		$count++;
+	    };
+	} else {
+	    die "invalid range: $part\n";
+	}
+    }
+
+    die "got empty cpuset for cgroup '$cgroup'\n"
+	if !$count;
+
+    return $cpuset;
+}
+
+sub write_to_cgroup {
+    my ($self, $cgroup) = @_;
+
+    my $filename = "/sys/fs/cgroup/cpuset/$cgroup/cpuset.cpus";
+
+    my $value = '';
+    my @members = $self->members();
+    foreach my $cpuid (@members) {
+	$value .= ',' if length($value);
+	$value .= $cpuid;
+    }
+
+    die "unable to write empty cpu set\n" if !length($value);
+
+    open(my $fh, '>', $filename) || die "failed to open '$filename' - $!\n";
+    PVE::Tools::safe_print($filename, $fh, "$value\n");
+    close($fh);
+}
+
+sub insert {
+    my ($self, @members) = @_;
+
+    my $count = 0;
+    
+    foreach my $cpu (@members) {
+	die "cpu id '$cpu' is out of range\n" if $cpu >= $MAX_CPUID;
+	next if $self->{members}->{$cpu};
+	$self->{members}->{$cpu} = 1;
+	$count++;
+    }
+
+    return $count;
+}
+
+sub delete {
+    my ($self, @members) = @_;
+
+    my $count = 0;
+    
+    foreach my $cpu (@members) {
+	die "cpu id '$cpu' is out of range\n" if $cpu >= $MAX_CPUID;
+	next if !$self->{members}->{$cpu};
+	delete $self->{members}->{$cpu};
+	$count++;
+    }
+
+    return $count;
+}
+
+sub has {
+   my ($self, $cpuid) = @_;
+
+   return $self->{members}->{$cpuid};
+}
+
+# members: this list is always sorted!
+sub members {
+    my ($self) = @_;
+
+    return sort keys %{$self->{members}};
+}    
+
+sub size {
+    my ($self) = @_;
+
+    return scalar(keys %{$self->{members}});
+}
+
+sub is_equal {
+    my ($self, $set2) = @_;
+
+    my $members1 = $self->{members};
+    my $members2 = $set2->{members};
+
+    foreach my $id (keys %$members1) {
+	return 0 if !$members2->{$id};
+    }
+    foreach my $id (keys %$members2) {
+	return 0 if !$members1->{$id};
+    }
+    
+    return 1;
+}
+
+1;