Re: [PATCH 3/3] add support for dynamicly allocation of mmu pages.

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Izik Eidus wrote:
> this patch all the functions that use the mmu pages
> it teach them how to use the new lists.
>   

> --- mmu.c	2007-08-15 11:37:08.000000000 +0300
> +++ new_mmu.c	2007-08-19 06:27:56.000000000 +0300
> @@ -586,14 +586,25 @@
>  static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm_vcpu *vcpu,
>  						gfn_t gfn)
>  {
> -	unsigned index;
> +	unsigned index, index_div_blocks;
>  	struct hlist_head *bucket;
>  	struct kvm_mmu_page *page;
>  	struct hlist_node *node;
> +	struct list_head *block_node;
> +	struct kvm_mmu_hash_block *hash_block;
> +	int i;
>  
>  	pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
> -	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
> -	bucket = &vcpu->kvm->mmu_page_hash[index];
> +	index = kvm_page_table_hashfn(gfn) % (KVM_NUM_MMU_PAGES_BLOCK *
> +				vcpu->kvm->n_mmu_page_hash_blocks);
> +	block_node = vcpu->kvm->mmu_page_hash_blocks.next;
> +	index_div_blocks = index / KVM_NUM_MMU_PAGES_BLOCK;
> +	
> +	for (i = 0; i < index_div_blocks; ++i)
> +		block_node = block_node->next;
> +	
> +	hash_block = list_entry(block_node, struct kvm_mmu_hash_block, head);
> +	bucket = &hash_block->mmu_page_hash[index % KVM_NUM_MMU_PAGES_BLOCK];
>   

This is slowing down kvm_mmu_lookup_page() for large memory guests.  
This is a frequently called function!


>  	hlist_for_each_entry(page, node, bucket, hash_link)
>  		if (page->gfn == gfn && !page->role.metaphysical) {
>  			pgprintk("%s: found role %x\n",
> @@ -612,11 +623,14 @@
>  					     u64 *parent_pte)
>  {
>  	union kvm_mmu_page_role role;
> -	unsigned index;
> +	unsigned index, index_div_blocks;
>  	unsigned quadrant;
>  	struct hlist_head *bucket;
>  	struct kvm_mmu_page *page;
>  	struct hlist_node *node;
> +	struct list_head *block_node;
> +	struct kvm_mmu_hash_block *hash_block;
> +	int i;
>  
>  	role.word = 0;
>  	role.glevels = vcpu->mmu.root_level;
> @@ -630,8 +644,16 @@
>  	}
>  	pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
>  		 gfn, role.word);
> -	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
> -	bucket = &vcpu->kvm->mmu_page_hash[index];
> +	index = kvm_page_table_hashfn(gfn) % (KVM_NUM_MMU_PAGES_BLOCK *
> +				vcpu->kvm->n_mmu_page_hash_blocks);
> +	block_node = vcpu->kvm->mmu_page_hash_blocks.next;
> +	index_div_blocks = index / KVM_NUM_MMU_PAGES_BLOCK;
> +	
> +	for (i = 0; i < index_div_blocks; ++i)
> +		block_node = block_node->next;
> +	
> +	hash_block = list_entry(block_node, struct kvm_mmu_hash_block, head);
> +	bucket = &hash_block->mmu_page_hash[index % KVM_NUM_MMU_PAGES_BLOCK];
>   

Code duplication, this is better extracted into a helper.

>  	hlist_for_each_entry(page, node, bucket, hash_link)
>  		if (page->gfn == gfn && page->role.word == role.word) {
>  			mmu_page_add_parent_pte(vcpu, page, parent_pte);
> @@ -716,16 +738,26 @@
>  
>  static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
>  {
> -	unsigned index;
> +	unsigned index, index_div_blocks;
>  	struct hlist_head *bucket;
>  	struct kvm_mmu_page *page;
>  	struct hlist_node *node, *n;
> -	int r;
> +	struct list_head *block_node;
> +	struct kvm_mmu_hash_block *hash_block;
> +	int r, i;
>  
>  	pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
>  	r = 0;
> -	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
> -	bucket = &vcpu->kvm->mmu_page_hash[index];
> +	index = kvm_page_table_hashfn(gfn) % (KVM_NUM_MMU_PAGES_BLOCK *
> +				vcpu->kvm->n_mmu_page_hash_blocks);
> +	block_node = vcpu->kvm->mmu_page_hash_blocks.next;
> +	index_div_blocks = index / KVM_NUM_MMU_PAGES_BLOCK;
> +	
> +	for (i = 0; i < index_div_blocks; ++i)
> +		block_node = block_node->next;
> +	
> +	hash_block = list_entry(block_node, struct kvm_mmu_hash_block, head);
> +	bucket = &hash_block->mmu_page_hash[index % KVM_NUM_MMU_PAGES_BLOCK];
>   

Likewise.

>  	hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
>  		if (page->gfn == gfn && !page->role.metaphysical) {
>  			pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
> @@ -1126,7 +1158,9 @@
>  	struct kvm_mmu_page *page;
>  	struct hlist_node *node, *n;
>  	struct hlist_head *bucket;
> -	unsigned index;
> +	struct list_head *block_node;
> +	struct kvm_mmu_hash_block *hash_block;
> +	unsigned index , index_div_blocks;
>  	u64 *spte;
>  	unsigned offset = offset_in_page(gpa);
>  	unsigned pte_size;
> @@ -1136,6 +1170,7 @@
>  	int level;
>  	int flooded = 0;
>  	int npte;
> +	int i;
>  
>  	pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
>  	if (gfn == vcpu->last_pt_write_gfn) {
> @@ -1146,8 +1181,16 @@
>  		vcpu->last_pt_write_gfn = gfn;
>  		vcpu->last_pt_write_count = 1;
>  	}
> -	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
> -	bucket = &vcpu->kvm->mmu_page_hash[index];
> +	index = kvm_page_table_hashfn(gfn) % (KVM_NUM_MMU_PAGES_BLOCK *
> +				vcpu->kvm->n_mmu_page_hash_blocks);
> +	block_node = vcpu->kvm->mmu_page_hash_blocks.next;
> +	index_div_blocks = index / KVM_NUM_MMU_PAGES_BLOCK;
> +	
> +	for (i = 0; i < index_div_blocks; ++i)
> +		block_node = block_node->next;
> +	
> +	hash_block = list_entry(block_node, struct kvm_mmu_hash_block, head);
> +	bucket = &hash_block->mmu_page_hash[index % KVM_NUM_MMU_PAGES_BLOCK];
>   

Ditto.


-- 
error compiling committee.c: too many arguments to function


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