On Friday 17 July 2009 17:56:49 sudhir kumar wrote: > On Fri, Jul 17, 2009 at 12:47 PM, Dor Laor<dlaor@xxxxxxxxxx> wrote: > > On 07/17/2009 08:50 AM, Zhang Qian wrote: > >> Hi, > >> > >> I have a KVM box which has 4GB physical memory totally, I'd like to > >> know how much I can use to run my domains, and how much will be > >> reserved by hypervisor(KVM) itself? > >> Thanks! > > > > KVM and the Linux host use relatively low amount of memory. > > Unlike other hypervisors you know, kvm does not reserve memory and also > > is able to swap the guest memory, so you can even use more than 4G for > > your > > Is that true? I think we can not allocate memory more than the > physical RAM. Or does upstream kvm supports it? My kvm version is not > that old but memory allocation failed for me when I tried to give the > whole memory on my host to the guest. It's not specific to KVM. QEmu use malloc()/mmap() to allocate memory for KVM, which is controlled by Linux kernel memory overcommit policy. Linux kernel didn't support memory overcommit by default. You can refer to Document/vm/overcommit-accounting and other related document to enable it. -- regards Yang, Sheng > > > guest. (Just note swapping will be slow) > > > >> Regards, > >> Qian > >> -- > >> To unsubscribe from this list: send the line "unsubscribe kvm" in > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > To unsubscribe from this list: send the line "unsubscribe kvm" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
