[PATCH 1/2] Use kmem cache for allocating vcpus

Rusty Russell
2007-07-30T11:12:19Z

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-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>

diff -r 650abbc45974 drivers/kvm/kvm.h
--- a/drivers/kvm/kvm.h Mon Jul 30 20:49:49 2007 +1000
+++ b/drivers/kvm/kvm.h Mon Jul 30 21:01:41 2007 +1000
@@ -140,6 +140,7 @@ 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
@@ -481,7 +482,8 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu,
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 -r 650abbc45974 drivers/kvm/kvm_main.c
--- a/drivers/kvm/kvm_main.c Mon Jul 30 20:49:49 2007 +1000
+++ b/drivers/kvm/kvm_main.c Mon Jul 30 21:05:13 2007 +1000
@@ -53,6 +53,8 @@ static cpumask_t cpus_hardware_enabled;
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);

#define STAT_OFFSET(x) offsetof(struct kvm_vcpu, stat.x)

@@ -3142,7 +3144,8 @@ static struct sys_device kvm_sysdev = {

hpa_t bad_page_address;

-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;

@@ -3180,6 +3183,14 @@ int kvm_init_arch(struct kvm_arch_ops *o
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);
@@ -3191,6 +3202,8 @@ int kvm_init_arch(struct kvm_arch_ops *o
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);
@@ -3208,6 +3221,7 @@ void kvm_exit_arch(void)
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 -r 650abbc45974 drivers/kvm/svm.c
--- a/drivers/kvm/svm.c Mon Jul 30 20:49:49 2007 +1000
+++ b/drivers/kvm/svm.c Mon Jul 30 21:00:05 2007 +1000
@@ -559,7 +559,7 @@ static struct kvm_vcpu *svm_create_vcpu(
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;
@@ -1832,7 +1832,8 @@ 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 -r 650abbc45974 drivers/kvm/vmx.c
--- a/drivers/kvm/vmx.c Mon Jul 30 20:49:49 2007 +1000
+++ b/drivers/kvm/vmx.c Mon Jul 30 21:08:52 2007 +1000
@@ -2295,7 +2295,7 @@ static struct kvm_vcpu *vmx_create_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);

if (!vmx)
return ERR_PTR(-ENOMEM);
@@ -2417,7 +2417,7 @@ 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;