[PATCH 037/104] KVM: Use kmem cache for allocating vcpus

Avi Kivity
2007-09-17T08:40:45Z

From: Rusty Russell <rusty@rustcorp.com.au>

Avi wants the allocations of vcpus centralized again. The easiest way
is to add a "size" arg to kvm_init_arch, and expose the thus-prepared
cache to the modules.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
drivers/kvm/kvm.h | 4 +++-
drivers/kvm/kvm_main.c | 16 +++++++++++++++-
drivers/kvm/svm.c | 5 +++--
drivers/kvm/vmx.c | 4 ++--
4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 030b93b..b362e8f 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -141,6 +141,7 @@ struct kvm_mmu_page {
};

struct kvm_vcpu;
+extern struct kmem_cache *kvm_vcpu_cache;

/*
* x86 supports 3 paging modes (4-level 64-bit, 3-level 64-bit, and 2-level
@@ -483,7 +484,8 @@ extern struct kvm_arch_ops *kvm_arch_ops;
int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
void kvm_vcpu_uninit(struct kvm_vcpu *vcpu);

-int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module);
+int kvm_init_arch(struct kvm_arch_ops *ops, unsigned int vcpu_size,
+ struct module *module);
void kvm_exit_arch(void);

int kvm_mmu_module_init(void);
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 4bbd89e..4166a08 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -53,6 +53,8 @@ static LIST_HEAD(vm_list);
static cpumask_t cpus_hardware_enabled;

struct kvm_arch_ops *kvm_arch_ops;
+struct kmem_cache *kvm_vcpu_cache;
+EXPORT_SYMBOL_GPL(kvm_vcpu_cache);

static __read_mostly struct preempt_ops kvm_preempt_ops;

@@ -3104,7 +3106,8 @@ static void kvm_sched_out(struct preempt_notifier *pn,
kvm_arch_ops->vcpu_put(vcpu);
}

-int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
+int kvm_init_arch(struct kvm_arch_ops *ops, unsigned int vcpu_size,
+ struct module *module)
{
int r;

@@ -3142,6 +3145,14 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
if (r)
goto out_free_3;

+ /* A kmem cache lets us meet the alignment requirements of fx_save. */
+ kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size,
+ __alignof__(struct kvm_vcpu), 0, 0);
+ if (!kvm_vcpu_cache) {
+ r = -ENOMEM;
+ goto out_free_4;
+ }
+
kvm_chardev_ops.owner = module;

r = misc_register(&kvm_dev);
@@ -3156,6 +3167,8 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
return r;

out_free:
+ kmem_cache_destroy(kvm_vcpu_cache);
+out_free_4:
sysdev_unregister(&kvm_sysdev);
out_free_3:
sysdev_class_unregister(&kvm_sysdev_class);
@@ -3173,6 +3186,7 @@ out:
void kvm_exit_arch(void)
{
misc_deregister(&kvm_dev);
+ kmem_cache_destroy(kvm_vcpu_cache);
sysdev_unregister(&kvm_sysdev);
sysdev_class_unregister(&kvm_sysdev_class);
unregister_reboot_notifier(&kvm_reboot_notifier);
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index b25f4e1..8193651 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -577,7 +577,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
struct page *page;
int err;

- svm = kzalloc(sizeof *svm, GFP_KERNEL);
+ svm = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
if (!svm) {
err = -ENOMEM;
goto out;
@@ -1849,7 +1849,8 @@ static struct kvm_arch_ops svm_arch_ops = {

static int __init svm_init(void)
{
- return kvm_init_arch(&svm_arch_ops, THIS_MODULE);
+ return kvm_init_arch(&svm_arch_ops, sizeof(struct vcpu_svm),
+ THIS_MODULE);
}

static void __exit svm_exit(void)
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index f770f55..2b30274 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2365,7 +2365,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
{
int err;
- struct vcpu_vmx *vmx = kzalloc(sizeof(*vmx), GFP_KERNEL);
+ struct vcpu_vmx *vmx = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
int cpu;

if (!vmx)
@@ -2490,7 +2490,7 @@ static int __init vmx_init(void)
memset(iova, 0xff, PAGE_SIZE);
kunmap(vmx_io_bitmap_b);

- r = kvm_init_arch(&vmx_arch_ops, THIS_MODULE);
+ r = kvm_init_arch(&vmx_arch_ops, sizeof(struct vcpu_vmx), THIS_MODULE);
if (r)
goto out1;

--
1.5.3