Commit 52d5dedc authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

Revert "KVM: MMU: reclaim the zapped-obsolete page first" 

Unwinding optimizations related to obsolete pages is a step towards
removing x86 KVM's fast invalidate mechanism, i.e. this is one part of
a revert all patches from the series that introduced the mechanism[1].

This reverts commit 365c8868.

[1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com



Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5ff05683

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -851,7 +851,6 @@ struct kvm_arch { 
	 * Hash table of struct kvm_mmu_page.

	 */

	struct list_head active_mmu_pages;

	struct list_head zapped_obsolete_pages;

	struct kvm_page_track_notifier_node mmu_sp_tracker;

	struct kvm_page_track_notifier_head track_notifier_head;

arch/x86/kvm/mmu.c

+4 −17
Original line number Diff line number Diff line
@@ -5858,6 +5858,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_slot_set_dirty); 
static void kvm_zap_obsolete_pages(struct kvm *kvm)

{

	struct kvm_mmu_page *sp, *node;

	LIST_HEAD(invalid_list);

	int batch = 0;



restart:
@@ -5890,8 +5891,7 @@ restart: 
			goto restart;

		}



		ret = kvm_mmu_prepare_zap_page(kvm, sp,

				&kvm->arch.zapped_obsolete_pages);

		ret = kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);

		batch += ret;



		if (ret)
@@ -5902,7 +5902,7 @@ restart: 
	 * Should flush tlb before free page tables since lockless-walking

	 * may use the pages.

	 */

	kvm_mmu_commit_zap_page(kvm, &kvm->arch.zapped_obsolete_pages);

	kvm_mmu_commit_zap_page(kvm, &invalid_list);

}



/*
@@ -5935,11 +5935,6 @@ void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm) 
	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 void kvm_mmu_zap_mmio_sptes(struct kvm *kvm)

{

	struct kvm_mmu_page *sp, *node;
@@ -6011,24 +6006,16 @@ mmu_shrink_scan(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 &&

		      !kvm_has_zapped_obsolete_pages(kvm))

		if (!kvm->arch.n_used_mmu_pages)

			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;

		}



		if (prepare_zap_oldest_mmu_page(kvm, &invalid_list))

			freed++;

		kvm_mmu_commit_zap_page(kvm, &invalid_list);



unlock:

		spin_unlock(&kvm->mmu_lock);

		srcu_read_unlock(&kvm->srcu, idx);

arch/x86/kvm/x86.c

+0 −1
Original line number Diff line number Diff line
@@ -9113,7 +9113,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) 


	INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list);

	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);

	INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);

	INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);

	atomic_set(&kvm->arch.noncoherent_dma_count, 0);

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