Message ID | 20200208154209.1797988-7-jolsa@kernel.org |
---|---|
State | Superseded |
Delegated to: | BPF Maintainers |
Headers | show |
Series | bpf: Add trampoline and dispatcher to /proc/kallsyms | expand |
On Sat, Feb 8, 2020 at 7:43 AM Jiri Olsa <jolsa@kernel.org> 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@kernel.org> > --- > 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); > } > [...]
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@kernel.org> 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@kernel.org> > > --- > > 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
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) +{ + 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 = { + .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; 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); } static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) @@ -623,6 +662,7 @@ static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) return; latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); + latch_tree_erase(&aux->ksym.tnode, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops); list_del_rcu(&aux->ksym.lnode); } @@ -671,19 +711,27 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) NULL; } +static struct bpf_ksym *bpf_ksym_find(unsigned long addr) +{ + struct latch_tree_node *n; + + n = latch_tree_find((void *)addr, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops); + return n ? container_of(n, struct bpf_ksym, tnode) : NULL; +} + const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, unsigned long *off, char *sym) { - struct bpf_prog *prog; + struct bpf_ksym *ksym; char *ret = NULL; rcu_read_lock(); - prog = bpf_prog_kallsyms_find(addr); - if (prog) { - unsigned long symbol_start = prog->aux->ksym.start; - unsigned long symbol_end = prog->aux->ksym.end; + ksym = bpf_ksym_find(addr); + if (ksym) { + unsigned long symbol_start = ksym->start; + unsigned long symbol_end = ksym->end; - strncpy(sym, prog->aux->ksym.name, KSYM_NAME_LEN); + strncpy(sym, ksym->name, KSYM_NAME_LEN); ret = sym; if (size)
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@kernel.org> --- include/linux/bpf.h | 1 + kernel/bpf/core.c | 60 ++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 55 insertions(+), 6 deletions(-)