diff options
| author | Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> | 2013-05-31 08:36:29 +0800 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-06-05 12:33:33 +0300 |
| commit | 365c886860c4ba670d245e762b23987c912c129a (patch) | |
| tree | 81f59edf5ba5e4c944d5590a631bbd23419e2cd8 /arch/x86/kvm/mmu.c | |
| parent | f34d251d66ba263c077ed9d2bbd1874339a4c887 (diff) | |
KVM: MMU: reclaim the zapped-obsolete page first
As Marcelo pointed out that
| "(retention of large number of pages while zapping)
| can be fatal, it can lead to OOM and host crash"
We introduce a list, kvm->arch.zapped_obsolete_pages, to link all
the pages which are deleted from the mmu cache but not actually
freed. When page reclaiming is needed, we always zap this kind of
pages first.
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 674c0442ac89..79af88ab2f1d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4211,7 +4211,6 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) static void kvm_zap_obsolete_pages(struct kvm *kvm) { struct kvm_mmu_page *sp, *node; - LIST_HEAD(invalid_list); int batch = 0; restart: @@ -4244,7 +4243,8 @@ restart: goto restart; } - ret = kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); + ret = kvm_mmu_prepare_zap_page(kvm, sp, + &kvm->arch.zapped_obsolete_pages); batch += ret; if (ret) @@ -4255,7 +4255,7 @@ restart: * Should flush tlb before free page tables since lockless-walking * may use the pages. */ - kvm_mmu_commit_zap_page(kvm, &invalid_list); + kvm_mmu_commit_zap_page(kvm, &kvm->arch.zapped_obsolete_pages); } /* @@ -4306,6 +4306,11 @@ restart: spin_unlock(&kvm->mmu_lock); } +static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm) +{ + return unlikely(!list_empty_careful(&kvm->arch.zapped_obsolete_pages)); +} + static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc) { struct kvm *kvm; @@ -4334,15 +4339,23 @@ static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc) * want to shrink a VM that only started to populate its MMU * anyway. */ - if (!kvm->arch.n_used_mmu_pages) + if (!kvm->arch.n_used_mmu_pages && + !kvm_has_zapped_obsolete_pages(kvm)) continue; idx = srcu_read_lock(&kvm->srcu); spin_lock(&kvm->mmu_lock); + if (kvm_has_zapped_obsolete_pages(kvm)) { + kvm_mmu_commit_zap_page(kvm, + &kvm->arch.zapped_obsolete_pages); + goto unlock; + } + prepare_zap_oldest_mmu_page(kvm, &invalid_list); kvm_mmu_commit_zap_page(kvm, &invalid_list); +unlock: spin_unlock(&kvm->mmu_lock); srcu_read_unlock(&kvm->srcu, idx); |