Re: [PATCH 2/3] memcg: unify slab and other kmem pages charging

From: Vladimir Davydov
Date: Sat Oct 17 2015 - 11:06:02 EST


On Fri, Oct 16, 2015 at 05:19:32PM -0700, Johannes Weiner wrote:
...
> I think it'd be better to have an outer function than a magic
> parameter for the memcg lookup. Could we fold this in there?

Yeah, that looks neater. Thanks!

Andrew, could you please fold this one too?

>
> ---
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 7 ++++---
> mm/memcontrol.c | 36 ++++++++++++++++++------------------
> mm/slab.h | 4 ++--
> 3 files changed, 24 insertions(+), 23 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 47677ac..730a65d 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -756,8 +756,9 @@ static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
> * conditions, but because they are pretty simple, they are expected to be
> * fast.
> */
> -int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order,
> - struct mem_cgroup *memcg);
> +int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
> + struct mem_cgroup *memcg);
> +int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
> void __memcg_kmem_uncharge(struct page *page, int order);
>
> /*
> @@ -797,7 +798,7 @@ static __always_inline int memcg_kmem_charge(struct page *page,
> {
> if (__memcg_kmem_bypass(gfp))
> return 0;
> - return __memcg_kmem_charge(page, gfp, order, NULL);
> + return __memcg_kmem_charge(page, gfp, order);
> }
>
> /**
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 15db655..6fc9959 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2378,39 +2378,39 @@ void __memcg_kmem_put_cache(struct kmem_cache *cachep)
> css_put(&cachep->memcg_params.memcg->css);
> }
>
> -/*
> - * If @memcg != NULL, charge to @memcg, otherwise charge to the memcg the
> - * current task belongs to.
> - */
> -int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order,
> - struct mem_cgroup *memcg)
> +int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
> + struct mem_cgroup *memcg)
> {
> - struct page_counter *counter;
> unsigned int nr_pages = 1 << order;
> - bool put = false;
> + struct page_counter *counter;
> int ret = 0;
>
> - if (!memcg) {
> - memcg = get_mem_cgroup_from_mm(current->mm);
> - put = true;
> - }
> if (!memcg_kmem_is_active(memcg))
> - goto out;
> + return 0;
>
> ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter);
> if (ret)
> - goto out;
> + return ret;
>
> ret = try_charge(memcg, gfp, nr_pages);
> if (ret) {
> page_counter_uncharge(&memcg->kmem, nr_pages);
> - goto out;
> + return ret;
> }
>
> page->mem_cgroup = memcg;
> -out:
> - if (put)
> - css_put(&memcg->css);
> +
> + return 0;
> +}
> +
> +int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
> +{
> + struct mem_cgroup *memcg;
> + int ret;
> +
> + memcg = get_mem_cgroup_from_mm(current->mm);
> + ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);
> + css_put(&memcg->css);
> return ret;
> }
>
> diff --git a/mm/slab.h b/mm/slab.h
> index 3d667a4..27492eb 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -244,8 +244,8 @@ static __always_inline int memcg_charge_slab(struct page *page,
> return 0;
> if (is_root_cache(s))
> return 0;
> - return __memcg_kmem_charge(page, gfp, order,
> - s->memcg_params.memcg);
> + return __memcg_kmem_charge_memcg(page, gfp, order,
> + s->memcg_params.memcg);
> }
>
> extern void slab_init_memcg_params(struct kmem_cache *);
--
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