hi,
I seem to have a problem with the Linux xen-network driver leaking skbs.
This is probably my own fault, upon resumption after migration I call
this:
void network_resume(void)
{
struct net_device* dev = __dev_get_by_name("eth0");
MOD_DEC_USE_COUNT;
network_open(dev);
}
-- which works fine. However, in network_open() the call to
NETOP_RESET_RINGS seems to clear all the pointers to the old skbs, and
network_alloc_rx_buffers() allocs a bunch of new ones. It suppose that
means I have just leaked a whole bunch of skbs. I know the standard
suspend/resume code performs almost a full ifup/ifdown (which I cannot
do in my case) but I don''t see any skb-freeing code in that case
either?
I have tried dev_kfree_skb()''ing the contents of the np->rx_skbs[1:]
array before calling network_open, but doing so just crashes Linux :-(
Any ideas?
Jacob
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> hi, > > I seem to have a problem with the Linux xen-network driver leaking skbs. > This is probably my own fault, upon resumption after migration I call > this: > > void network_resume(void) > { > struct net_device* dev = __dev_get_by_name("eth0"); > MOD_DEC_USE_COUNT; > > network_open(dev); > } > > -- which works fine. However, in network_open() the call to > NETOP_RESET_RINGS seems to clear all the pointers to the old skbs, and > network_alloc_rx_buffers() allocs a bunch of new ones. It suppose that > means I have just leaked a whole bunch of skbs. I know the standard > suspend/resume code performs almost a full ifup/ifdown (which I cannot > do in my case) but I don''t see any skb-freeing code in that case either? > > I have tried dev_kfree_skb()''ing the contents of the np->rx_skbs[1:] > array before calling network_open, but doing so just crashes Linux :-( > > Any ideas? > > JacobThe correct suspend behaviour is caused by executing dev->stop(). Why are you not able to run the existing ifdown/ifup code? It doesn''t execute notifier lists so shouldn''t affect routing tables or anything like that. -- Keir ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Jacob Gorm Hansen
2004-Apr-22 10:23 UTC
Re: [Xen-devel] Resetting network device / skb leak
On Thu, 2004-04-22 at 08:19, Keir Fraser wrote:> The correct suspend behaviour is caused by executing dev->stop(). > > Why are you not able to run the existing ifdown/ifup code? It doesn''t > execute notifier lists so shouldn''t affect routing tables or anything > like that.Mainly because I need the interface to remain active across the point where I am checkpointing the system -- the interface is used in the migration which is still ongoing at that time (I firewall off unrelated connections to not mess things up externally). Basically I need to revive the (already open but not Xen-connected/initialised) interface when I wake up, which the previously quoted code does fine, but apparently this causes a leak of skbs. What I am looking for is a safe way of freeing or reusing the old ones before reinitialising the interface. Jacob ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> On Thu, 2004-04-22 at 08:19, Keir Fraser wrote: > > The correct suspend behaviour is caused by executing dev->stop(). > > > > Why are you not able to run the existing ifdown/ifup code? It doesn''t > > execute notifier lists so shouldn''t affect routing tables or anything > > like that. > > Mainly because I need the interface to remain active across the point > where I am checkpointing the system -- the interface is used in the > migration which is still ongoing at that time (I firewall off unrelated > connections to not mess things up externally). > > Basically I need to revive the (already open but not > Xen-connected/initialised) interface when I wake up, which the > previously quoted code does fine, but apparently this causes a leak of > skbs. What I am looking for is a safe way of freeing or reusing the old > ones before reinitialising the interface. > > Jacob >So you even do the final parts of state migration within the domain that is migrating? That sounds hard to get right. :-) -- Keir ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Jacob Gorm Hansen
2004-Apr-22 10:46 UTC
Re: [Xen-devel] Resetting network device / skb leak
On Thu, 2004-04-22 at 12:28, Keir Fraser wrote:> So you even do the final parts of state migration within the domain > that is migrating? That sounds hard to get right. :-)Otherwise it wouldn''t be as much fun ;-) I _think_ this leak is the last part that is missing (apart from block device migration which I am not currently addressing, and some hard-coded limitations on the size of the migrating guest OS), I suppose I should release a patch soon if anyone is interested. Jacob ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel