Sort memslots base on its size and use line search to find it, so the larger
memslots have better fit
The idea is from Avi
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
---
include/linux/kvm_host.h | 22 +++++++++---
virt/kvm/kvm_main.c | 82 ++++++++++++++++++++++++++++++++-------------
2 files changed, 75 insertions(+), 29 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a0e4d63..83b396a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -230,8 +230,12 @@ struct kvm_irq_routing_table {};
#define KVM_MEM_SLOTS_NUM (KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
#endif
+/*
+ * Note:
+ * memslots are not sorted by id anymore, please use id_to_memslot()
+ * to get the memslot by its id.
+ */
struct kvm_memslots {
- int nmemslots;
u64 generation;
struct kvm_memory_slot memslots[KVM_MEM_SLOTS_NUM];
};
@@ -307,9 +311,10 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
(vcpup = kvm_get_vcpu(kvm, idx)) != NULL; \
idx++)
-#define kvm_for_each_memslot(slots, memslot, i) \
- for (i = 0; i < (slots)->nmemslots && \
- ({ memslot = &(slots)->memslots[i]; 1; }); i++)
+#define kvm_for_each_memslot(slots, memslot, i) \
+ for (i = 0; i < KVM_MEM_SLOTS_NUM && \
+ ({ memslot = &(slots)->memslots[i]; 1; }) && \
+ memslot->npages != 0; i++)
int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
void kvm_vcpu_uninit(struct kvm_vcpu *vcpu);
@@ -335,7 +340,14 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm)
static inline struct kvm_memory_slot *
id_to_memslot(struct kvm_memslots *slots, int id)
{
- return &slots->memslots[id];
+ int i;
+
+ for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+ if (slots->memslots[i].id == id)
+ return &slots->memslots[i];
+
+ WARN_ON(1);
+ return NULL;
}
#define HPA_MSB ((sizeof(hpa_t) * 8) - 1)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 09bb794..9425e3a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -440,6 +440,15 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
+static void kvm_init_memslots_id(struct kvm *kvm)
+{
+ int i;
+ struct kvm_memslots *slots = kvm->memslots;
+
+ for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+ slots->memslots[i].id = i;
+}
+
static struct kvm *kvm_create_vm(void)
{
int r, i;
@@ -465,6 +474,7 @@ static struct kvm *kvm_create_vm(void)
kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
if (!kvm->memslots)
goto out_err_nosrcu;
+ kvm_init_memslots_id(kvm);
if (init_srcu_struct(&kvm->srcu))
goto out_err_nosrcu;
for (i = 0; i < KVM_NR_BUSES; i++) {
@@ -630,15 +640,55 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
}
#endif /* !CONFIG_S390 */
+static struct kvm_memory_slot *
+search_memslots(struct kvm_memslots *slots, gfn_t gfn)
+{
+ int i;
+ struct kvm_memory_slot *memslot;
+
+ kvm_for_each_memslot(slots, memslot, i)
+ if (gfn >= memslot->base_gfn &&
+ gfn < memslot->base_gfn + memslot->npages)
+ return memslot;
+
+ return NULL;
+}
+
+static int cmp_memslot(const void *slot1, const void *slot2)
+{
+ struct kvm_memory_slot *s1, *s2;
+
+ s1 = (struct kvm_memory_slot *)slot1;
+ s2 = (struct kvm_memory_slot *)slot2;
+
+ if (s1->npages < s2->npages)
+ return 1;
+ if (s1->npages > s2->npages)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * Sort the memslots base on its size, so the larger slots
+ * will get better fit.
+ */
+static void sort_memslots(struct kvm_memslots *slots)
+{
+ sort(slots->memslots, KVM_MEM_SLOTS_NUM,
+ sizeof(struct kvm_memory_slot), cmp_memslot, NULL);
+}
+
void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
{
if (new) {
int id = new->id;
struct kvm_memory_slot *old = id_to_memslot(slots, id);
+ unsigned long npages = old->npages;
*old = *new;
- if (id >= slots->nmemslots)
- slots->nmemslots = id + 1;
+ if (new->npages != npages)
+ sort_memslots(slots);
}
slots->generation++;
@@ -979,16 +1029,7 @@ EXPORT_SYMBOL_GPL(kvm_is_error_hva);
static struct kvm_memory_slot *__gfn_to_memslot(struct kvm_memslots *slots,
gfn_t gfn)
{
- int i;
-
- for (i = 0; i < slots->nmemslots; ++i) {
- struct kvm_memory_slot *memslot = &slots->memslots[i];
-
- if (gfn >= memslot->base_gfn
- && gfn < memslot->base_gfn + memslot->npages)
- return memslot;
- }
- return NULL;
+ return search_memslots(slots, gfn);
}
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
@@ -999,20 +1040,13 @@ EXPORT_SYMBOL_GPL(gfn_to_memslot);
int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{
- int i;
- struct kvm_memslots *slots = kvm_memslots(kvm);
+ struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
- for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
- struct kvm_memory_slot *memslot = &slots->memslots[i];
-
- if (memslot->flags & KVM_MEMSLOT_INVALID)
- continue;
+ if (!memslot || memslot->id >= KVM_MEMORY_SLOTS ||
+ memslot->flags & KVM_MEMSLOT_INVALID)
+ return 0;
- if (gfn >= memslot->base_gfn
- && gfn < memslot->base_gfn + memslot->npages)
- return 1;
- }
- return 0;
+ return 1;
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
--
1.7.7.1
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