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    [from the cache]
©2003-2011 Jasper Spaans