KVM: MMU: Use slab caches for shadow pages and their headers
Use slab caches instead of a simple custom list.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index c85c664..46491b4 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -165,6 +165,8 @@
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
+static struct kmem_cache *mmu_page_cache;
+static struct kmem_cache *mmu_page_header_cache;
static int is_write_protection(struct kvm_vcpu *vcpu)
{
@@ -235,6 +237,14 @@
goto out;
r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
rmap_desc_cache, 1, gfp_flags);
+ if (r)
+ goto out;
+ r = mmu_topup_memory_cache(&vcpu->mmu_page_cache,
+ mmu_page_cache, 4, gfp_flags);
+ if (r)
+ goto out;
+ r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
+ mmu_page_header_cache, 4, gfp_flags);
out:
return r;
}
@@ -258,6 +268,8 @@
{
mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);
mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);
+ mmu_free_memory_cache(&vcpu->mmu_page_cache);
+ mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
}
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
@@ -458,7 +470,9 @@
struct kvm_mmu_page *page_head)
{
ASSERT(is_empty_shadow_page(page_head->spt));
- list_move(&page_head->link, &vcpu->free_pages);
+ list_del(&page_head->link);
+ mmu_memory_cache_free(&vcpu->mmu_page_cache, page_head->spt);
+ mmu_memory_cache_free(&vcpu->mmu_page_header_cache, page_head);
++vcpu->kvm->n_free_mmu_pages;
}
@@ -472,11 +486,14 @@
{
struct kvm_mmu_page *page;
- if (list_empty(&vcpu->free_pages))
+ if (!vcpu->kvm->n_free_mmu_pages)
return NULL;
- page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link);
- list_move(&page->link, &vcpu->kvm->active_mmu_pages);
+ page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache,
+ sizeof *page);
+ page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
+ set_page_private(virt_to_page(page->spt), (unsigned long)page);
+ list_add(&page->link, &vcpu->kvm->active_mmu_pages);
ASSERT(is_empty_shadow_page(page->spt));
page->slot_bitmap = 0;
page->multimapped = 0;
@@ -1083,6 +1100,7 @@
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
+ mmu_topup_memory_caches(vcpu);
if (!is_paging(vcpu))
return nonpaging_init_context(vcpu);
else if (is_long_mode(vcpu))
@@ -1256,13 +1274,6 @@
struct kvm_mmu_page, link);
kvm_mmu_zap_page(vcpu, page);
}
- while (!list_empty(&vcpu->free_pages)) {
- page = list_entry(vcpu->free_pages.next,
- struct kvm_mmu_page, link);
- list_del(&page->link);
- free_page((unsigned long)page->spt);
- page->spt = NULL;
- }
free_page((unsigned long)vcpu->mmu.pae_root);
}
@@ -1273,18 +1284,7 @@
ASSERT(vcpu);
- for (i = 0; i < KVM_NUM_MMU_PAGES; i++) {
- struct kvm_mmu_page *page_header = &vcpu->page_header_buf[i];
-
- INIT_LIST_HEAD(&page_header->link);
- if ((page = alloc_page(GFP_KERNEL)) == NULL)
- goto error_1;
- set_page_private(page, (unsigned long)page_header);
- page_header->spt = page_address(page);
- memset(page_header->spt, 0, PAGE_SIZE);
- list_add(&page_header->link, &vcpu->free_pages);
- ++vcpu->kvm->n_free_mmu_pages;
- }
+ vcpu->kvm->n_free_mmu_pages = KVM_NUM_MMU_PAGES;
/*
* When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
@@ -1309,7 +1309,6 @@
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
- ASSERT(list_empty(&vcpu->free_pages));
return alloc_mmu_pages(vcpu);
}
@@ -1318,7 +1317,6 @@
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
- ASSERT(!list_empty(&vcpu->free_pages));
return init_kvm_mmu(vcpu);
}
@@ -1377,6 +1375,10 @@
kmem_cache_destroy(pte_chain_cache);
if (rmap_desc_cache)
kmem_cache_destroy(rmap_desc_cache);
+ if (mmu_page_cache)
+ kmem_cache_destroy(mmu_page_cache);
+ if (mmu_page_header_cache)
+ kmem_cache_destroy(mmu_page_header_cache);
}
int kvm_mmu_module_init(void)
@@ -1392,6 +1394,18 @@
if (!rmap_desc_cache)
goto nomem;
+ mmu_page_cache = kmem_cache_create("kvm_mmu_page",
+ PAGE_SIZE,
+ PAGE_SIZE, 0, NULL, NULL);
+ if (!mmu_page_cache)
+ goto nomem;
+
+ mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
+ sizeof(struct kvm_mmu_page),
+ 0, 0, NULL, NULL);
+ if (!mmu_page_header_cache)
+ goto nomem;
+
return 0;
nomem: