I am looking at patching the xm mem-set problem described in: http://lists.xensource.com/archives/html/xen-devel/2006-05/msg00122.html While doing this I came across a few other issues. 1. "xm mem-set <DomID> 32M" causes DomU / Dom0 to freeze irrespective of initial memory size. There is no output on the serial console when this happens so I am not sure where exactly the DomU is crashing. I know doing this is harsh but I think a check is required that will prevent users from shooting themselves in the foot. 2. I am able to do "xm mem-set <DomID> 8G" even if the total system memory is only 4GB. "xm list" reflects the 8GB value. Isn''t this also a bug? It looks like there needs to be a few sanity checks for mem-set. I am wondering what the best place to do this is. Should it be in Xend or the balloon driver? Thanks, Aravindh Puthiyaparambil Xen Development Team Unisys Tredyffrin, PA E-Mail: aravindh.puthiyaparambil@unisys.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 11 May 2006, at 20:41, Puthiyaparambil, Aravindh wrote:> 1. "xm mem-set <DomID> 32M" causes DomU / Dom0 to freeze irrespective > of initial memory size. There is no output on the serial console when > this happens so I am not sure where exactly the DomU is crashing. I > know doing this is harsh but I think a check is required that will > prevent users from shooting themselves in the foot.Possibly. Perhaps a min-mem parameter in the xend config file or something like that.> 2. I am able to do "xm mem-set <DomID> 8G" even if the total system > memory is only 4GB. "xm list" reflects the 8GB value. Isn''t this also > a bug?The bug here is that ''xm list'' shows the current target allocation for the guest (as specified to mem-set) rather than what the guest is currently using. It''d be good to fix this. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> Possibly. Perhaps a min-mem parameter in the xend config file or > something like that.I see that there is a dom0-min-mem parameter in the xend config file. But I am able to do "xm mem-set 0 32M" and shoot myself in the foot. :-) I guess the parameter is having no effect. I will look into this.> The bug here is that ''xm list'' shows the current target allocation for > the guest (as specified to mem-set) rather than what the guest is > currently using. It''d be good to fix this.I thought the balloon driver was going through with the increase. I will send in a fix for this too. And for the mem-set to less that 2% of initial memory issue, I am assuming the check should go in the balloon driver. Am I right? Thanks, Aravindh _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 11 May 2006, at 22:26, Puthiyaparambil, Aravindh wrote:>> The bug here is that ''xm list'' shows the current target allocation for >> the guest (as specified to mem-set) rather than what the guest is >> currently using. It''d be good to fix this. > > I thought the balloon driver was going through with the increase. I > will > send in a fix for this too.It''ll go as far as it can, subject to its reservation cap and subject to physical memory limitations of the host system. The balloon driver and the memory targetting system are working okay here I think.> And for the mem-set to less that 2% of initial memory issue, I am > assuming the check should go in the balloon driver. Am I right?That would probably be a good idea. I''d prefer a more dynamic check that hooked off Linux low-memory paths (e.g., steps in before the OOM killer) and got the balloon driver to back off. That would work in a wider range of situations. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel