[pve-devel] [PATCH] add memory_unplug support V2

[Alexandre Derumier]

qemu 2.4 feature

changelog: rebase on last git

Note that currently linux guest don't support unplug of dimm when it'sused by kernel memory.
They are some tunning to do with memory zone movable.
http://events.linuxfoundation.org/sites/events/files/lcjp13_chen.pdf

Signed-off-by: Alexandre Derumier <aderumier at odiso.com>
---
 PVE/QemuServer.pm | 101 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 83 insertions(+), 18 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index c0a9b20..84fc712 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2495,6 +2495,27 @@ sub foreach_dimm {
     }
 }
 
+sub foreach_reverse_dimm {
+    my ($conf, $vmid, $memory, $sockets, $func) = @_;
+
+    my $dimm_id = 253;
+    my $current_size = 4177920;
+    my $dimm_size = 65536;
+    return if $current_size == $memory;
+
+    for (my $j = 0; $j < 8; $j++) {
+	for (my $i = 0; $i < 32; $i++) {
+ 	    my $name = "dimm${dimm_id}";
+ 	    $dimm_id--;
+ 	    my $numanode = $i % $sockets;
+ 	    $current_size -= $dimm_size;
+ 	    &$func($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory);
+	    return  $current_size if $current_size <= $memory;
+	}
+	$dimm_size /= 2;
+    }
+}
+
 sub foreach_drive {
     my ($conf, $func) = @_;
 
@@ -3578,33 +3599,77 @@ sub qemu_memory_hotplug {
     my $dimm_memory = $memory - $static_memory;
 
     die "memory can't be lower than $static_memory MB" if $value < $static_memory;
-    die "memory unplug is not yet available" if $value < $memory;
     die "you cannot add more memory than $MAX_MEM MB!\n" if $memory > $MAX_MEM;
 
 
     my $sockets = 1;
     $sockets = $conf->{sockets} if $conf->{sockets};
 
-    foreach_dimm($conf, $vmid, $value, $sockets, sub {
-	my ($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory) = @_;
+    if($value > $memory) {
 
-	    return if $current_size <= $conf->{memory};
+    	foreach_dimm($conf, $vmid, $value, $sockets, sub {
+	    my ($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory) = @_;
 
-	    eval { vm_mon_cmd($vmid, "object-add", 'qom-type' => "memory-backend-ram", id => "mem-$name", props => { size => int($dimm_size*1024*1024) } ) };
-	    if (my $err = $@) {
-	        eval { qemu_objectdel($vmid, "mem-$name"); };
-	        die $err;
-	    }
+		return if $current_size <= $conf->{memory};
 
-	    eval { vm_mon_cmd($vmid, "device_add", driver => "pc-dimm", id => "$name", memdev => "mem-$name", node => $numanode) };
-	    if (my $err = $@) {
-	        eval { qemu_objectdel($vmid, "mem-$name"); };
-	        die $err;
-	    }
-	    #update conf after each succesful module hotplug
-	    $conf->{memory} = $current_size;
-	    update_config_nolock($vmid, $conf, 1);
-    });
+		eval { vm_mon_cmd($vmid, "object-add", 'qom-type' => "memory-backend-ram", id => "mem-$name", props => { size => int($dimm_size*1024*1024) } ) };
+		if (my $err = $@) {
+		    eval { qemu_objectdel($vmid, "mem-$name"); };
+		    die $err;
+		}
+
+		eval { vm_mon_cmd($vmid, "device_add", driver => "pc-dimm", id => "$name", memdev => "mem-$name", node => $numanode) };
+		if (my $err = $@) {
+		    eval { qemu_objectdel($vmid, "mem-$name"); };
+		    die $err;
+		}
+		#update conf after each succesful module hotplug
+		$conf->{memory} = $current_size;
+		update_config_nolock($vmid, $conf, 1);
+	});
+
+    } else {
+
+    	foreach_reverse_dimm($conf, $vmid, $value, $sockets, sub {
+	    my ($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory) = @_;
+
+		return if $current_size >= $conf->{memory};
+		print "try to unplug memory dimm $name\n";
+
+		my $retry = 0;
+	        while (1) {
+		    eval { qemu_devicedel($vmid, $name) };
+		    sleep 3;
+		    my $dimm_list = qemu_dimm_list($vmid);
+		    last if !$dimm_list->{$name};
+		    raise_param_exc({ $name => "error unplug memory module" }) if $retry > 5;
+		    $retry++;
+		}
+
+		#update conf after each succesful module unplug
+		$conf->{memory} = $current_size;
+
+		eval { qemu_objectdel($vmid, "mem-$name"); };
+		update_config_nolock($vmid, $conf, 1);
+	});
+    }
+}
+
+sub qemu_dimm_list {
+    my ($vmid) = @_;
+
+    my $dimmarray = vm_mon_cmd_nocheck($vmid, "query-memory-devices");
+    my $dimms = {};
+
+    foreach my $dimm (@$dimmarray) {
+
+        $dimms->{$dimm->{data}->{id}}->{id} = $dimm->{data}->{id};
+        $dimms->{$dimm->{data}->{id}}->{node} = $dimm->{data}->{node};
+        $dimms->{$dimm->{data}->{id}}->{addr} = $dimm->{data}->{addr};
+        $dimms->{$dimm->{data}->{id}}->{size} = $dimm->{data}->{size};
+        $dimms->{$dimm->{data}->{id}}->{slot} = $dimm->{data}->{slot};
+    }
+    return $dimms;
 }
 
 sub qemu_block_set_io_throttle {
-- 
2.1.4