linux-kernel - Re: [PATCH bpf-next 2/5] bpf: add memlock precharge for socket local storage

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Date:   Thu, 30 May 2019 11:26:48 -0700
From:   Song Liu <liu.song.a23@...il.com>
To:     Roman Gushchin <guro@...com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        bpf <bpf@...r.kernel.org>, Kernel Team <kernel-team@...com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH bpf-next 2/5] bpf: add memlock precharge for socket local storage

On Wed, May 29, 2019 at 6:05 PM Roman Gushchin <guro@...com> wrote:
>
> Socket local storage maps lack the memlock precharge check,
> which is performed before the memory allocation for
> most other bpf map types.
>
> Let's add it in order to unify all map types.
>
> Signed-off-by: Roman Gushchin <guro@...com>

Acked-by: Song Liu <songliubraving@...com>

> ---
>  net/core/bpf_sk_storage.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
> index cc9597a87770..9a8aaf8e235d 100644
> --- a/net/core/bpf_sk_storage.c
> +++ b/net/core/bpf_sk_storage.c
> @@ -626,7 +626,9 @@ static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
>         struct bpf_sk_storage_map *smap;
>         unsigned int i;
>         u32 nbuckets;
> +       u32 pages;
>         u64 cost;
> +       int ret;
>
>         smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN);
>         if (!smap)
> @@ -635,13 +637,19 @@ static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
>
>         smap->bucket_log = ilog2(roundup_pow_of_two(num_possible_cpus()));
>         nbuckets = 1U << smap->bucket_log;
> +       cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap);
> +       pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
> +
> +       ret = bpf_map_precharge_memlock(pages);
> +       if (ret < 0)
> +               return ERR_PTR(ret);
> +
>         smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets,
>                                  GFP_USER | __GFP_NOWARN);
>         if (!smap->buckets) {
>                 kfree(smap);
>                 return ERR_PTR(-ENOMEM);
>         }
> -       cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap);
>
>         for (i = 0; i < nbuckets; i++) {
>                 INIT_HLIST_HEAD(&smap->buckets[i].list);
> @@ -651,7 +659,7 @@ static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
>         smap->elem_size = sizeof(struct bpf_sk_storage_elem) + attr->value_size;
>         smap->cache_idx = (unsigned int)atomic_inc_return(&cache_idx) %
>                 BPF_SK_STORAGE_CACHE_SIZE;
> -       smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
> +       smap->map.pages = pages;
>
>         return &smap->map;
>  }
> --
> 2.20.1
>