On Tue, Feb 11, 2020 at 10:21:10AM -0800, Andrii Nakryiko wrote:
> 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?
I followed the other latch tree ops functions and did not think
much about that.. will check
>
> > +{
> > + 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?
right, should be bpf_ksym_tree_ops as you said
>
> > + .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?
right, thanks
jirka
