linux-kernel - [PATCH v2] KVM: x86/mmu: move reused pages to the top of active_mmu

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Message-ID: <20260129030231.567759-1-someguy@effective-light.com>
Date: Wed, 28 Jan 2026 22:02:30 -0500
From: Hamza Mahfooz <someguy@...ective-light.com>
To: kvm@...r.kernel.org
Cc: Hamza Mahfooz <someguy@...ective-light.com>,
	Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Thomas Gleixner <tglx@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] KVM: x86/mmu: move reused pages to the top of active_mmu_pages

Move reused shadow pages to the head of active_mmu_pages in
kvm_mmu_find_shadow_page(). This will allow us to move towards more of
a LRU approximation eviction strategy instead of just straight FIFO.

Signed-off-by: Hamza Mahfooz <someguy@...ective-light.com>
---
v2: move logic to kvm_mmu_find_shadow_page().
---
 arch/x86/kvm/mmu/mmu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 02c450686b4a..d89099ba1fca 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2325,6 +2325,9 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm,
 out:
 	kvm_mmu_commit_zap_page(kvm, &invalid_list);
 
+	if (sp && !list_is_head(&sp->link, &kvm->arch.active_mmu_pages))
+		list_move(&sp->link, &kvm->arch.active_mmu_pages);
+
 	if (collisions > kvm->stat.max_mmu_page_hash_collisions)
 		kvm->stat.max_mmu_page_hash_collisions = collisions;
 	return sp;
-- 
2.52.0