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SubjectRe: [PATCH 29/48] perf callchain: Maintain libunwind's address space in map_groups
Em Thu, Sep 13, 2018 at 02:54:31PM +0200, Jiri Olsa escreveu:
> Currently the address_space was kept in thread struct but it's more
> appropriate to keep it in map_groups as it's maintained throughout
> exec's with timestamps. Also we should not flush the address space
> after exec since it still can be accessed when used with an indexed
> data file.
>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Link: http://lkml.kernel.org/n/tip-hjryh6x2yfnrz8g0djhez24z@git.kernel.org
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/map.h | 5 ++++-
> tools/perf/util/thread.h | 1 -
> tools/perf/util/unwind-libunwind-local.c | 28 ++++++++++++++----------
> tools/perf/util/unwind-libunwind.c | 9 ++++----
> tools/perf/util/unwind.h | 7 +++---
> 5 files changed, 29 insertions(+), 21 deletions(-)
>
> diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> index 02c6f6962eb1..b1efe57b8563 100644
> --- a/tools/perf/util/map.h
> +++ b/tools/perf/util/map.h
> @@ -65,10 +65,13 @@ struct maps {
>
> struct map_groups {
> struct maps maps;
> - struct machine *machine;
> + struct machine *machine;
> refcount_t refcnt;
> u64 timestamp;
> struct list_head list;

Hey, avoid these distractions, this doesn't change anything and besides
having the * aligned with the names of non-pointers is what is common
practice, see for instance 'struct task_struct', 'struct inode', to name
just two widely used structs in the kernel source :-)

I'll get these two fixed up, i.e. remove the above hunk, align the one
below :-)

- Arnaldo

> +#ifdef HAVE_LIBUNWIND_SUPPORT
> + void *addr_space;
> +#endif
> };
>
> struct map_groups *map_groups__new(struct machine *machine);
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 86186a0773a0..637775f622b3 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -40,7 +40,6 @@ struct thread {
> struct thread_stack *ts;
> struct nsinfo *nsinfo;
> #ifdef HAVE_LIBUNWIND_SUPPORT
> - void *addr_space;
> struct unwind_libunwind_ops *unwind_libunwind_ops;
> #endif
> };
> diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
> index da6f39315b47..f7c921f87bcf 100644
> --- a/tools/perf/util/unwind-libunwind-local.c
> +++ b/tools/perf/util/unwind-libunwind-local.c
> @@ -617,32 +617,35 @@ static unw_accessors_t accessors = {
> .get_proc_name = get_proc_name,
> };
>
> -static int _unwind__prepare_access(struct thread *thread)
> +static int _unwind__prepare_access(struct map_groups *mg)
> {
> if (!dwarf_callchain_users)
> return 0;
> - thread->addr_space = unw_create_addr_space(&accessors, 0);
> - if (!thread->addr_space) {
> +
> + mg->addr_space = unw_create_addr_space(&accessors, 0);
> + if (!mg->addr_space) {
> pr_err("unwind: Can't create unwind address space.\n");
> return -ENOMEM;
> }
>
> - unw_set_caching_policy(thread->addr_space, UNW_CACHE_GLOBAL);
> + unw_set_caching_policy(mg->addr_space, UNW_CACHE_GLOBAL);
> return 0;
> }
>
> -static void _unwind__flush_access(struct thread *thread)
> +static void _unwind__flush_access(struct map_groups *mg)
> {
> if (!dwarf_callchain_users)
> return;
> - unw_flush_cache(thread->addr_space, 0, 0);
> +
> + unw_flush_cache(mg->addr_space, 0, 0);
> }
>
> -static void _unwind__finish_access(struct thread *thread)
> +static void _unwind__finish_access(struct map_groups *mg)
> {
> if (!dwarf_callchain_users)
> return;
> - unw_destroy_addr_space(thread->addr_space);
> +
> + unw_destroy_addr_space(mg->addr_space);
> }
>
> static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
> @@ -650,7 +653,6 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
> {
> u64 val;
> unw_word_t ips[max_stack];
> - unw_addr_space_t addr_space;
> unw_cursor_t c;
> int ret, i = 0;
>
> @@ -666,13 +668,15 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
> * unwind itself.
> */
> if (max_stack - 1 > 0) {
> + struct map_groups *mg;
> +
> WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
> - addr_space = ui->thread->addr_space;
>
> - if (addr_space == NULL)
> + mg = thread__get_map_groups(ui->thread, ui->sample->time);
> + if (mg == NULL || mg->addr_space == NULL)
> return -1;
>
> - ret = unw_init_remote(&c, addr_space, ui);
> + ret = unw_init_remote(&c, mg->addr_space, ui);
> if (ret)
> display_error(ret);
>
> diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
> index b029a5e9ae49..ce8408e460f2 100644
> --- a/tools/perf/util/unwind-libunwind.c
> +++ b/tools/perf/util/unwind-libunwind.c
> @@ -18,12 +18,13 @@ static void unwind__register_ops(struct thread *thread,
> int unwind__prepare_access(struct thread *thread, struct map *map,
> bool *initialized)
> {
> + struct map_groups *mg = thread->mg;
> const char *arch;
> enum dso_type dso_type;
> struct unwind_libunwind_ops *ops = local_unwind_libunwind_ops;
> int err;
>
> - if (thread->addr_space) {
> + if (mg->addr_space) {
> pr_debug("unwind: thread map already set, dso=%s\n",
> map->dso->name);
> if (initialized)
> @@ -56,7 +57,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
> out_register:
> unwind__register_ops(thread, ops);
>
> - err = thread->unwind_libunwind_ops->prepare_access(thread);
> + err = thread->unwind_libunwind_ops->prepare_access(thread->mg);
> if (initialized)
> *initialized = err ? false : true;
> return err;
> @@ -65,13 +66,13 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
> void unwind__flush_access(struct thread *thread)
> {
> if (thread->unwind_libunwind_ops)
> - thread->unwind_libunwind_ops->flush_access(thread);
> + thread->unwind_libunwind_ops->flush_access(thread->mg);
> }
>
> void unwind__finish_access(struct thread *thread)
> {
> if (thread->unwind_libunwind_ops)
> - thread->unwind_libunwind_ops->finish_access(thread);
> + thread->unwind_libunwind_ops->finish_access(thread->mg);
> }
>
> int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
> diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
> index 8a44a1569a21..0f18a0858904 100644
> --- a/tools/perf/util/unwind.h
> +++ b/tools/perf/util/unwind.h
> @@ -9,6 +9,7 @@ struct map;
> struct perf_sample;
> struct symbol;
> struct thread;
> +struct map_groups;
>
> struct unwind_entry {
> struct map *map;
> @@ -19,9 +20,9 @@ struct unwind_entry {
> typedef int (*unwind_entry_cb_t)(struct unwind_entry *entry, void *arg);
>
> struct unwind_libunwind_ops {
> - int (*prepare_access)(struct thread *thread);
> - void (*flush_access)(struct thread *thread);
> - void (*finish_access)(struct thread *thread);
> + int (*prepare_access)(struct map_groups *mg);
> + void (*flush_access)(struct map_groups *mg);
> + void (*finish_access)(struct map_groups *mg);
> int (*get_entries)(unwind_entry_cb_t cb, void *arg,
> struct thread *thread,
> struct perf_sample *data, int max_stack);
> --
> 2.17.1

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