Re: 2.6.25-rc5-git5 KVM memory not freed

[Avi Kivity]

Avi Kivity wrote:
> Ioan Ionita wrote:
> > Hi,
> >
> > I'm using KVM and the qemu kvm modified to run a windows guest. I'm
> > allocating 900 MB to the guest. Seems that when I terminate a qemu
> > process, the memory that was allocated to qemu is not freed:
> >
> >
> > Mem:       2058140    1739156     318984          0     226944     
> > 425140
> > -/+ buffers/cache:    1087072     971068
> > Swap:            0          0          0
> >
> > So I'm using 1GB of ram even though I've terminated qemu. If I attempt
> > to start qemu again, the machine locks up. No message in the logs.
> >
> > Command to start qemu:
> > /usr/local/kvm/bin/qemu-system-x86_64 b.data -no-acpi -m 900 -net nic
> > -net user -hdb temp.raw -usbdevice tablet
> >
> > uname -a
> > Linux ops-desktop 2.6.25-rc5-git5 #1 SMP PREEMPT Sat Mar 15 14:47:25
> > EET 2008 x86_64 GNU/Linux
> >
> >
> > Not sure whether this is a problem on the kernel side.  I don't
> > pretend to understand linux memory management. But it wasn't occurring
> > with older kernels. I'll attempt to bisect.
> >   
>
> I reproduced this and am investigating.

Attached patch ought to fix this.

--
error compiling committee.c: too many arguments to function

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4ba85d9..e55af12 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1412,7 +1412,7 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	up_read(&current->mm->mmap_sem);
 
 	vcpu->arch.update_pte.gfn = gfn;
-	vcpu->arch.update_pte.page = gfn_to_page(vcpu->kvm, gfn);
+	vcpu->arch.update_pte.page = page;
 }
 
 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,