diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2008-09-16 20:54:47 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2008-10-15 14:25:06 +0200 |
| commit | 4c2155ce81c193788082d4b8cdbc26d79edebc58 (patch) | |
| tree | 5c028fe4a18c55b5c0e9c4e80be459dad3f96da7 /virt | |
| parent | 777b3f49d297e387866604093b635e5bc9b9d2a6 (diff) | |
| download | lwn-4c2155ce81c193788082d4b8cdbc26d79edebc58.tar.gz lwn-4c2155ce81c193788082d4b8cdbc26d79edebc58.zip | |
KVM: switch to get_user_pages_fast
Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless
pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7%
faster on VMX.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2907d05cfcc3..cd34f73513d3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -723,9 +723,6 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_hva); -/* - * Requires current->mm->mmap_sem to be held - */ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) { struct page *page[1]; @@ -741,20 +738,23 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) return page_to_pfn(bad_page); } - npages = get_user_pages(current, current->mm, addr, 1, 1, 0, page, - NULL); + npages = get_user_pages_fast(addr, 1, 1, page); if (unlikely(npages != 1)) { struct vm_area_struct *vma; + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, addr); + if (vma == NULL || addr < vma->vm_start || !(vma->vm_flags & VM_PFNMAP)) { + up_read(¤t->mm->mmap_sem); get_page(bad_page); return page_to_pfn(bad_page); } pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; + up_read(¤t->mm->mmap_sem); BUG_ON(!is_mmio_pfn(pfn)); } else pfn = page_to_pfn(page[0]); |