diff options
| author | Marcelo Tosatti <marcelo@kvack.org> | 2008-02-23 11:44:30 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-04-27 11:53:25 +0300 |
| commit | 05da45583de9b383dc81dd695fe248431d6c9f2b (patch) | |
| tree | a76d699e60aca4f775d5f67254214654235e2e17 /virt | |
| parent | 2e53d63acba75795aa226febd140f67c58c6a353 (diff) | |
| download | lwn-05da45583de9b383dc81dd695fe248431d6c9f2b.tar.gz lwn-05da45583de9b383dc81dd695fe248431d6c9f2b.zip | |
KVM: MMU: large page support
Create large pages mappings if the guest PTE's are marked as such and
the underlying memory is hugetlbfs backed. If the largepage contains
write-protected pages, a large pte is not used.
Gives a consistent 2% improvement for data copies on ram mounted
filesystem, without NPT/EPT.
Anthony measures a 4% improvement on 4-way kernbench, with NPT.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c41eb57ce29b..31db9b4d3016 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -212,9 +212,13 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free, if (!dont || free->dirty_bitmap != dont->dirty_bitmap) vfree(free->dirty_bitmap); + if (!dont || free->lpage_info != dont->lpage_info) + vfree(free->lpage_info); + free->npages = 0; free->dirty_bitmap = NULL; free->rmap = NULL; + free->lpage_info = NULL; } void kvm_free_physmem(struct kvm *kvm) @@ -324,6 +328,25 @@ int __kvm_set_memory_region(struct kvm *kvm, new.user_alloc = user_alloc; new.userspace_addr = mem->userspace_addr; } + if (npages && !new.lpage_info) { + int largepages = npages / KVM_PAGES_PER_HPAGE; + if (npages % KVM_PAGES_PER_HPAGE) + largepages++; + if (base_gfn % KVM_PAGES_PER_HPAGE) + largepages++; + + new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info)); + + if (!new.lpage_info) + goto out_free; + + memset(new.lpage_info, 0, largepages * sizeof(*new.lpage_info)); + + if (base_gfn % KVM_PAGES_PER_HPAGE) + new.lpage_info[0].write_count = 1; + if ((base_gfn+npages) % KVM_PAGES_PER_HPAGE) + new.lpage_info[largepages-1].write_count = 1; + } /* Allocate page dirty bitmap if needed */ if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) { @@ -467,7 +490,7 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); -static unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) +unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) { struct kvm_memory_slot *slot; |