Izik Eidus wrote:
> this is the shrinker patch with all comments applied beside adding aging
> mechanism
> it look like the aging mechanism is not really needed and therefor for now it
> isn't
> implemented.
>
> From 8503a57ae88ba819e4eac6371172772c98b485f0 Mon Sep 17 00:00:00 2001
> From: Izik Eidus <[EMAIL PROTECTED]>
> Date: Tue, 25 Mar 2008 14:03:27 +0200
> Subject: [PATCH] KVM: register the kvm mmu cache with the shrinker.
>
> Signed-off-by: Izik Eidus <[EMAIL PROTECTED]>
> ---
> arch/x86/kvm/mmu.c | 54
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 54 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index c67ec62..c42c0db 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1972,6 +1972,57 @@ void kvm_mmu_zap_all(struct kvm *kvm)
> kvm_flush_remote_tlbs(kvm);
> }
> +static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
> +{
> + struct kvm *kvm;
> + struct kvm *kvm_freed = NULL;
> + int cache_count = 0;
> +
> + spin_lock(&kvm_lock);
> + if (list_empty(&vm_list)) {
> + spin_unlock(&kvm_lock);
> + return 0;
> + }
>
Unnecessary, if the list is empty the loop below doesn't execute and we
return 0 anyway.
> + list_for_each_entry(kvm, &vm_list, vm_list) {
> + int npages;
> +
> + spin_lock(&kvm->mmu_lock);
> + npages = kvm->arch.n_alloc_mmu_pages -
> + kvm->arch.n_free_mmu_pages;
> + cache_count += npages - KVM_MIN_ALLOC_MMU_PAGES;
>
I think we should allow the shrinker to go below
KVM_MIN_ALLOC_MMU_PAGES; in particular, if the vm is inactive, we should
be able to shrink it to nothing.
When the VM starts executing again, it will reallocate those pages.
> + if (!kvm_freed && nr_to_scan > 0 && npages >
> + KVM_MIN_ALLOC_MMU_PAGES) {
>
Don't split an expression like that; the tightly binding expression
should stay on the same line:
if (!kvm_freed && nr_to_scan > 0 &&
npages > KVM_MN_ALLOC_MMU_PAGES) {
> + kvm_mmu_remove_one_alloc_mmu_page(kvm);
> + cache_count--;
> + kvm_freed = kvm;
> + }
> + nr_to_scan--;
> +
> + spin_unlock(&kvm->mmu_lock);
> + }
> + if (kvm_freed) {
> + list_del(&kvm_freed->vm_list);
> + list_add_tail(&kvm_freed->vm_list, &vm_list);
> + }
>
list_move_tail()
> + spin_unlock(&kvm_lock);
> +
> + return cache_count;
> +}
> +
> +static struct shrinker mmu_shrinker = {
> + .shrink = mmu_shrink,
> + .seeks = DEFAULT_SEEKS * 10,
> +};
> +
> void kvm_mmu_module_exit(void)
> {
> if (pte_chain_cache)
> @@ -1980,6 +2031,7 @@ void kvm_mmu_module_exit(void)
> kmem_cache_destroy(rmap_desc_cache);
> if (mmu_page_header_cache)
> kmem_cache_destroy(mmu_page_header_cache);
>
>
I believe it is necessary to register the shrinker in order to have any
observable effect.
--
error compiling committee.c: too many arguments to function
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