On Sat, Feb 8, 2020 at 7:43 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> The bpf_tree is used both for kallsyms iterations and searching
> for exception tables of bpf programs, which is needed only for
> bpf programs.
>
> Adding bpf_kallsyms_tree that will hold symbols for all bpf_prog,
> bpf_trampoline and bpf_dispatcher objects and keeping bpf_tree
> only for bpf_prog objects exception tables search to keep it fast.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> include/linux/bpf.h | 1 +
> kernel/bpf/core.c | 60 ++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 55 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index da67ca3afa2f..151d7b1c8435 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -468,6 +468,7 @@ struct bpf_ksym {
> unsigned long end;
> char name[KSYM_NAME_LEN];
> struct list_head lnode;
> + struct latch_tree_node tnode;
> };
>
> enum bpf_tramp_prog_type {
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index b9b7077e60f3..1daa72341450 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -606,8 +606,46 @@ static const struct latch_tree_ops bpf_tree_ops = {
> .comp = bpf_tree_comp,
> };
>
> +static __always_inline unsigned long
> +bpf_get_ksym_start(struct latch_tree_node *n)
I thought static functions are never marked as inline in kernel
sources. Are there some special cases when its ok/necessary?
> +{
> + const struct bpf_ksym *ksym;
> +
> + ksym = container_of(n, struct bpf_ksym, tnode);
> + return ksym->start;
> +}
> +
> +static __always_inline bool
> +bpf_ksym_tree_less(struct latch_tree_node *a,
> + struct latch_tree_node *b)
> +{
> + return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
> +}
> +
> +static __always_inline int
> +bpf_ksym_tree_comp(void *key, struct latch_tree_node *n)
> +{
> + unsigned long val = (unsigned long)key;
> + const struct bpf_ksym *ksym;
> +
> + ksym = container_of(n, struct bpf_ksym, tnode);
> +
> + if (val < ksym->start)
> + return -1;
> + if (val >= ksym->end)
> + return 1;
> +
> + return 0;
> +}
> +
> +static const struct latch_tree_ops bpf_kallsyms_tree_ops = {
Given all the helper functions use bpf_ksym_tree and bpf_ksym
(bpf_ksym_find) prefixes, call this bpf_ksym_tree_ops?
> + .less = bpf_ksym_tree_less,
> + .comp = bpf_ksym_tree_comp,
> +};
> +
> static DEFINE_SPINLOCK(bpf_lock);
> static LIST_HEAD(bpf_kallsyms);
> +static struct latch_tree_root bpf_kallsyms_tree __cacheline_aligned;
same as above, bpf_ksym_tree for consistency?
> static struct latch_tree_root bpf_tree __cacheline_aligned;
>
> static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
> @@ -615,6 +653,7 @@ static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
> WARN_ON_ONCE(!list_empty(&aux->ksym.lnode));
> list_add_tail_rcu(&aux->ksym.lnode, &bpf_kallsyms);
> latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
> + latch_tree_insert(&aux->ksym.tnode, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops);
> }
>
[...]
