From: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
This will be used for mmu_shrink() in the following patch.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 36 ++++++++++++++++++++++++++----------
1 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b1e8270..fcd0dd1 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2003,6 +2003,28 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
}
+/**
+ * pre_zap_some_sp - make some shadow pages ready for being freed
+ * @kvm: the kvm instance
+ * @invalid_list: the list to which we add shadow pages ready for being freed
+ * @nr_to_zap: how many shadow pages we want to zap
+ *
+ * Try to make @nr_to_zap shadow pages ready for being freed, then put them
+ * into the @invalid_list.
+ *
+ * Return the number of shadow pages actually added to the @invalid_list.
+ */
+static int pre_zap_some_sp(struct kvm *kvm, struct list_head *invalid_list,
+ int nr_to_zap)
+{
+ int nr_before = kvm->arch.n_used_mmu_pages;
+
+ while (nr_to_zap > 0 && !list_empty(&kvm->arch.active_mmu_pages))
+ nr_to_zap -= pre_zap_one_sp(kvm, invalid_list);
+
+ return nr_before - kvm->arch.n_used_mmu_pages;
+}
+
/*
* Changing the number of mmu pages allocated to the vm
* Note: if goal_nr_mmu_pages is too small, you will get dead lock
@@ -2010,17 +2032,11 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
{
LIST_HEAD(invalid_list);
- /*
- * If we set the number of mmu pages to be smaller be than the
- * number of actived pages , we must to free some mmu pages before we
- * change the value
- */
+ int nr_to_zap = kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages;
- if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
- while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
- !list_empty(&kvm->arch.active_mmu_pages)) {
- pre_zap_one_sp(kvm, &invalid_list);
- }
+ if (nr_to_zap > 0) {
+ /* free some shadow pages to make the number fit the goal */
+ pre_zap_some_sp(kvm, &invalid_list, nr_to_zap);
kvm_mmu_commit_zap_page(kvm, &invalid_list);
goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
}
--
1.7.5.4
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