From 5a4c92880493945678315a6df810f7a21f55b985 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Thu, 3 Jul 2008 18:33:02 -0300 Subject: [PATCH] KVM: mmu_shrink: kvm_mmu_zap_page requires slots_lock to be held kvm_mmu_zap_page() needs slots lock held (rmap_remove->gfn_to_memslot, for example). Since kvm_lock spinlock is held in mmu_shrink(), do a non-blocking down_read_trylock(). Untested. Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 1fd8e3b58cc0..ff7cf632175b 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1987,6 +1987,8 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask) list_for_each_entry(kvm, &vm_list, vm_list) { int npages; + if (!down_read_trylock(&kvm->slots_lock)) + continue; spin_lock(&kvm->mmu_lock); npages = kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages; @@ -1999,6 +2001,7 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask) nr_to_scan--; spin_unlock(&kvm->mmu_lock); + up_read(&kvm->slots_lock); } if (kvm_freed) list_move_tail(&kvm_freed->vm_list, &vm_list);