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authorTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>2012-05-20 13:15:07 +0900
committerAvi Kivity <avi@redhat.com>2012-06-05 16:29:49 +0300
commitc1a7b32a14138f908df52d7c53b5ce3415ec6b50 (patch)
tree6f61d847e217212de98c8bdc9563ef09e25019e1
parent92eca8faad2d1b136c939bc122842dcdabd6ff46 (diff)
downloadop-kernel-dev-c1a7b32a14138f908df52d7c53b5ce3415ec6b50.zip
op-kernel-dev-c1a7b32a14138f908df52d7c53b5ce3415ec6b50.tar.gz
KVM: Avoid wasting pages for small lpage_info arrays
lpage_info is created for each large level even when the memory slot is not for RAM. This means that when we add one slot for a PCI device, we end up allocating at least KVM_NR_PAGE_SIZES - 1 pages by vmalloc(). To make things worse, there is an increasing number of devices which would result in more pages being wasted this way. This patch mitigates this problem by using kvm_kvzalloc(). Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
-rw-r--r--arch/x86/kvm/x86.c4
-rw-r--r--include/linux/kvm_host.h3
-rw-r--r--virt/kvm/kvm_main.c4
3 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index be6d549..f12a524 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6304,7 +6304,7 @@ void kvm_arch_free_memslot(struct kvm_memory_slot *free,
for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
if (!dont || free->arch.lpage_info[i] != dont->arch.lpage_info[i]) {
- vfree(free->arch.lpage_info[i]);
+ kvm_kvfree(free->arch.lpage_info[i]);
free->arch.lpage_info[i] = NULL;
}
}
@@ -6323,7 +6323,7 @@ int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
slot->base_gfn, level) + 1;
slot->arch.lpage_info[i] =
- vzalloc(lpages * sizeof(*slot->arch.lpage_info[i]));
+ kvm_kvzalloc(lpages * sizeof(*slot->arch.lpage_info[i]));
if (!slot->arch.lpage_info[i])
goto out_free;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c446435..19b83f6 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -535,6 +535,9 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);
void kvm_free_physmem(struct kvm *kvm);
+void *kvm_kvzalloc(unsigned long size);
+void kvm_kvfree(const void *addr);
+
#ifndef __KVM_HAVE_ARCH_VM_ALLOC
static inline struct kvm *kvm_arch_alloc_vm(void)
{
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1148c96..02cb440 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -520,7 +520,7 @@ out_err_nodisable:
* Avoid using vmalloc for a small buffer.
* Should not be used when the size is statically known.
*/
-static void *kvm_kvzalloc(unsigned long size)
+void *kvm_kvzalloc(unsigned long size)
{
if (size > PAGE_SIZE)
return vzalloc(size);
@@ -528,7 +528,7 @@ static void *kvm_kvzalloc(unsigned long size)
return kzalloc(size, GFP_KERNEL);
}
-static void kvm_kvfree(const void *addr)
+void kvm_kvfree(const void *addr)
{
if (is_vmalloc_addr(addr))
vfree(addr);
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