Re: [PATCH 4.14 108/159] kvm, mm: account kvm related kmem slabs to kmemcg

Michal Hocko
2017-12-22T09:35:03Z

On Fri 22-12-17 09:46:33, Greg KH wrote:
> 4.14-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Shakeel Butt <shakeelb@google.com>
>
>
> [ Upstream commit 46bea48ac241fe0b413805952dda74dd0c09ba8b ]
>
> The kvm slabs can consume a significant amount of system memory
> and indeed in our production environment we have observed that
> a lot of machines are spending significant amount of memory that
> can not be left as system memory overhead. Also the allocations
> from these slabs can be triggered directly by user space applications
> which has access to kvm and thus a buggy application can leak
> such memory. So, these caches should be accounted to kmemcg.
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The patch is not marked for stable, neither it fixes an existing bug.
It is a nice to have thing for sure but I am wondering how this got
through stable-filter.

> ---
> arch/x86/kvm/mmu.c | 4 ++--
> virt/kvm/kvm_main.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -5476,13 +5476,13 @@ int kvm_mmu_module_init(void)
>
> pte_list_desc_cache = kmem_cache_create("pte_list_desc",
> sizeof(struct pte_list_desc),
> - 0, 0, NULL);
> + 0, SLAB_ACCOUNT, NULL);
> if (!pte_list_desc_cache)
> goto nomem;
>
> mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
> sizeof(struct kvm_mmu_page),
> - 0, 0, NULL);
> + 0, SLAB_ACCOUNT, NULL);
> if (!mmu_page_header_cache)
> goto nomem;
>
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4018,7 +4018,7 @@ int kvm_init(void *opaque, unsigned vcpu
> if (!vcpu_align)
> vcpu_align = __alignof__(struct kvm_vcpu);
> kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size, vcpu_align,
> - 0, NULL);
> + SLAB_ACCOUNT, NULL);
> if (!kvm_vcpu_cache) {
> r = -ENOMEM;
> goto out_free_3;
>

--
Michal Hocko
SUSE Labs