[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] Balloon Driver Documentation/Description
Mark Williamson wrote: >> i'm looking for some documentation on how the balloon driver works >> internally. >> >> Can anybody give me a hint were i can find some good doku? > > Basically, the balloon driver allocates memory using standard kernel > allocation functions, then gives it back to Xen. The memory is no longer > available to use in the guest at this point, and the fact that it was > allocated by the balloon driver prevents the rest of the kernel from trying > to use it. > > When the balloon driver reclaims memory, it gets it back from Xen and then > does a "free", allowing the kernel memory allocator to give it to other > drivers for normal use. > That is my understanding of the balloon driver. What i do not understand is, if the balloon driver consists just of a frontend part in DomU that is allocating some memory, and a backend driver in Dom0, that gives that memory back, why is the output of the free command correct? What i want to say is the following: xendom1:~ # free total used free Mem: 786432 117104 669328 xendom1:~ # echo -n "536870912" > /proc/xen/balloon xendom1:~ # free total used free Mem: 524288 116664 407624 Why is the total amount of RAM also changing. If the balloon driver just allocates the memory, the used value should raise, but the total value should stay. I am not a kernel hacker, but i think i need to take a look into the code to understand that. Greetings, -timo -- Timo Benk - Jabber ID: fry@xxxxxxxxxx - ICQ ID: #241877854 PGP Public Key: http://m28s01.vlinux.de/timo_benk_gpg_key.asc _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |