From 3ee16c814511cd58f956b47b9c7654f57f674688 Mon Sep 17 00:00:00 2001 From: Izik Eidus Date: Sun, 30 Mar 2008 15:17:21 +0300 Subject: [PATCH] KVM: MMU: allow the vm to shrink the kvm mmu shadow caches Allow the Linux memory manager to reclaim memory in the kvm shadow cache. Signed-off-by: Izik Eidus Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 56 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c563283cb98..1594ee06c92 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1966,7 +1966,53 @@ void kvm_mmu_zap_all(struct kvm *kvm) kvm_flush_remote_tlbs(kvm); } -void kvm_mmu_module_exit(void) +void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm) +{ + struct kvm_mmu_page *page; + + page = container_of(kvm->arch.active_mmu_pages.prev, + struct kvm_mmu_page, link); + kvm_mmu_zap_page(kvm, page); +} + +static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask) +{ + struct kvm *kvm; + struct kvm *kvm_freed = NULL; + int cache_count = 0; + + spin_lock(&kvm_lock); + + list_for_each_entry(kvm, &vm_list, vm_list) { + int npages; + + spin_lock(&kvm->mmu_lock); + npages = kvm->arch.n_alloc_mmu_pages - + kvm->arch.n_free_mmu_pages; + cache_count += npages; + if (!kvm_freed && nr_to_scan > 0 && npages > 0) { + kvm_mmu_remove_one_alloc_mmu_page(kvm); + cache_count--; + kvm_freed = kvm; + } + nr_to_scan--; + + spin_unlock(&kvm->mmu_lock); + } + if (kvm_freed) + list_move_tail(&kvm_freed->vm_list, &vm_list); + + spin_unlock(&kvm_lock); + + return cache_count; +} + +static struct shrinker mmu_shrinker = { + .shrink = mmu_shrink, + .seeks = DEFAULT_SEEKS * 10, +}; + +void mmu_destroy_caches(void) { if (pte_chain_cache) kmem_cache_destroy(pte_chain_cache); @@ -1976,6 +2022,12 @@ void kvm_mmu_module_exit(void) kmem_cache_destroy(mmu_page_header_cache); } +void kvm_mmu_module_exit(void) +{ + mmu_destroy_caches(); + unregister_shrinker(&mmu_shrinker); +} + int kvm_mmu_module_init(void) { pte_chain_cache = kmem_cache_create("kvm_pte_chain", @@ -1995,10 +2047,12 @@ int kvm_mmu_module_init(void) if (!mmu_page_header_cache) goto nomem; + register_shrinker(&mmu_shrinker); + return 0; nomem: - kvm_mmu_module_exit(); + mmu_destroy_caches(); return -ENOMEM; }