lkml.org 
[lkml]   [2008]   [Jul]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 10/19] KVM: mmu_shrink: kvm_mmu_zap_page requires slots_lock to be held
    Date
    From: Marcelo Tosatti <mtosatti@redhat.com>

    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 <avi@qumranet.com>
    ---
    arch/x86/kvm/mmu.c | 3 +++
    1 files changed, 3 insertions(+), 0 deletions(-)

    diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
    index 1fd8e3b..ff7cf63 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);
    --
    1.5.6.1


    \
     
     \ /
      Last update: 2008-07-15 14:19    [W:0.021 / U:97.908 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site