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-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/mmu.c34
-rw-r--r--arch/x86/mm/gup.c3
-rw-r--r--include/linux/mmu_notifier.h26
-rw-r--r--mm/huge_memory.c6
-rw-r--r--mm/mmu_notifier.c20
-rw-r--r--virt/kvm/kvm_main.c17
7 files changed, 105 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index aa75f21..ffd7f8d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -822,6 +822,7 @@ extern bool kvm_rebooting;
#define KVM_ARCH_WANT_MMU_NOTIFIER
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
int kvm_age_hva(struct kvm *kvm, unsigned long hva);
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
int cpuid_maxphyaddr(struct kvm_vcpu *vcpu);
int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 47b2c32..f02b8ed 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -945,6 +945,35 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
return young;
}
+static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
+ unsigned long data)
+{
+ u64 *spte;
+ int young = 0;
+
+ /*
+ * If there's no access bit in the secondary pte set by the
+ * hardware it's up to gup-fast/gup to set the access bit in
+ * the primary pte or in the page structure.
+ */
+ if (!shadow_accessed_mask)
+ goto out;
+
+ spte = rmap_next(kvm, rmapp, NULL);
+ while (spte) {
+ u64 _spte = *spte;
+ BUG_ON(!(_spte & PT_PRESENT_MASK));
+ young = _spte & PT_ACCESSED_MASK;
+ if (young) {
+ young = 1;
+ break;
+ }
+ spte = rmap_next(kvm, rmapp, spte);
+ }
+out:
+ return young;
+}
+
#define RMAP_RECYCLE_THRESHOLD 1000
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
@@ -965,6 +994,11 @@ int kvm_age_hva(struct kvm *kvm, unsigned long hva)
return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
}
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+{
+ return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
+}
+
#ifdef MMU_DEBUG
static int is_empty_shadow_page(u64 *spt)
{
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 269aa53..dbe34b9 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -8,6 +8,7 @@
#include <linux/mm.h>
#include <linux/vmstat.h>
#include <linux/highmem.h>
+#include <linux/swap.h>
#include <asm/pgtable.h>
@@ -89,6 +90,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
get_page(page);
+ SetPageReferenced(page);
pages[*nr] = page;
(*nr)++;
@@ -103,6 +105,7 @@ static inline void get_head_page_multiple(struct page *page, int nr)
VM_BUG_ON(page != compound_head(page));
VM_BUG_ON(page_count(page) == 0);
atomic_add(nr, &page->_count);
+ SetPageReferenced(page);
}
static inline void get_huge_page_tail(struct page *page)
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index cbfab1e..cc2e7df 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -62,6 +62,16 @@ struct mmu_notifier_ops {
unsigned long address);
/*
+ * test_young is called to check the young/accessed bitflag in
+ * the secondary pte. This is used to know if the page is
+ * frequently used without actually clearing the flag or tearing
+ * down the secondary mapping on the page.
+ */
+ int (*test_young)(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long address);
+
+ /*
* change_pte is called in cases that pte mapping to page is changed:
* for example, when ksm remaps pte to point to a new shared page.
*/
@@ -163,6 +173,8 @@ extern void __mmu_notifier_mm_destroy(struct mm_struct *mm);
extern void __mmu_notifier_release(struct mm_struct *mm);
extern int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
unsigned long address);
+extern int __mmu_notifier_test_young(struct mm_struct *mm,
+ unsigned long address);
extern void __mmu_notifier_change_pte(struct mm_struct *mm,
unsigned long address, pte_t pte);
extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
@@ -186,6 +198,14 @@ static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
return 0;
}
+static inline int mmu_notifier_test_young(struct mm_struct *mm,
+ unsigned long address)
+{
+ if (mm_has_notifiers(mm))
+ return __mmu_notifier_test_young(mm, address);
+ return 0;
+}
+
static inline void mmu_notifier_change_pte(struct mm_struct *mm,
unsigned long address, pte_t pte)
{
@@ -313,6 +333,12 @@ static inline int mmu_notifier_clear_flush_young(struct mm_struct *mm,
return 0;
}
+static inline int mmu_notifier_test_young(struct mm_struct *mm,
+ unsigned long address)
+{
+ return 0;
+}
+
static inline void mmu_notifier_change_pte(struct mm_struct *mm,
unsigned long address, pte_t pte)
{
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 915809b..39d7df4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1632,7 +1632,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
VM_BUG_ON(PageLRU(page));
/* If there is no mapped pte young don't collapse the page */
- if (pte_young(pteval))
+ if (pte_young(pteval) || PageReferenced(page) ||
+ mmu_notifier_test_young(vma->vm_mm, address))
referenced = 1;
}
if (unlikely(!referenced))
@@ -1892,7 +1893,8 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
/* cannot use mapcount: can't collapse if there's a gup pin */
if (page_count(page) != 1)
goto out_unmap;
- if (pte_young(pteval))
+ if (pte_young(pteval) || PageReferenced(page) ||
+ mmu_notifier_test_young(vma->vm_mm, address))
referenced = 1;
}
if (referenced)
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 438951d..8d032de 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -100,6 +100,26 @@ int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
return young;
}
+int __mmu_notifier_test_young(struct mm_struct *mm,
+ unsigned long address)
+{
+ struct mmu_notifier *mn;
+ struct hlist_node *n;
+ int young = 0;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(mn, n, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->test_young) {
+ young = mn->ops->test_young(mn, mm, address);
+ if (young)
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return young;
+}
+
void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address,
pte_t pte)
{
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 85ab7db..4286d47 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -380,6 +380,22 @@ static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
return young;
}
+static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long address)
+{
+ struct kvm *kvm = mmu_notifier_to_kvm(mn);
+ int young, idx;
+
+ idx = srcu_read_lock(&kvm->srcu);
+ spin_lock(&kvm->mmu_lock);
+ young = kvm_test_age_hva(kvm, address);
+ spin_unlock(&kvm->mmu_lock);
+ srcu_read_unlock(&kvm->srcu, idx);
+
+ return young;
+}
+
static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
@@ -396,6 +412,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
.invalidate_range_end = kvm_mmu_notifier_invalidate_range_end,
.clear_flush_young = kvm_mmu_notifier_clear_flush_young,
+ .test_young = kvm_mmu_notifier_test_young,
.change_pte = kvm_mmu_notifier_change_pte,
.release = kvm_mmu_notifier_release,
};
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