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KVM: sort memslots by its size and use line search

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Sort memslots base on its size and use line search to find it, so that the
larger memslots have better fit

The idea is from Avi

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Xiao Guangrong 2011-11-24 17:40:57 +08:00 committed by Avi Kivity
parent 28a37544fb
commit bf3e05bc1e
2 changed files with 72 additions and 25 deletions
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18
include/linux/kvm_host.h
View file

@ -231,8 +231,12 @@ 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];
};
@ -310,7 +314,8 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
#define kvm_for_each_memslot(memslot, slots) \
for (memslot = &slots->memslots[0]; \
memslot < slots->memslots + (slots)->nmemslots; memslot++)
memslot < slots->memslots + KVM_MEM_SLOTS_NUM && memslot->npages;\
memslot++)
int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
void kvm_vcpu_uninit(struct kvm_vcpu *vcpu);
@ -336,7 +341,14 @@ 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)

79
virt/kvm/kvm_main.c
View file

@ -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 +640,54 @@ 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)
{
struct kvm_memory_slot *memslot;
kvm_for_each_memslot(memslot, slots)
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++;
@ -980,14 +1029,7 @@ EXPORT_SYMBOL_GPL(kvm_is_error_hva);
static struct kvm_memory_slot *__gfn_to_memslot(struct kvm_memslots *slots,
gfn_t gfn)
{
struct kvm_memory_slot *memslot;
kvm_for_each_memslot(memslot, slots)
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)
@ -998,20 +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 || memslot->id >= KVM_MEMORY_SLOTS ||
memslot->flags & KVM_MEMSLOT_INVALID)
return 0;
if (memslot->flags & KVM_MEMSLOT_INVALID)
continue;
if (gfn >= memslot->base_gfn
&& gfn < memslot->base_gfn + memslot->npages)
return 1;
}
return 0;
return 1;
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);