[PATCH 1/2] perf map: use zalloc for map_groups

[PATCH 1/2] perf map: use zalloc for map_groups

[John Keeping]

In the next commit we will add new fields to map_groups and we need
these to be null if no value is assigned.  The simplest way to achieve
this is to request zeroed memory from the allocator.

Signed-off-by: John Keeping <john@metanate.com>
---
 tools/perf/util/map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 668410b1d426..44b556812e4b 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -636,7 +636,7 @@ bool map_groups__empty(struct map_groups *mg)
 
 struct map_groups *map_groups__new(struct machine *machine)
 {
-	struct map_groups *mg = malloc(sizeof(*mg));
+	struct map_groups *mg = zalloc(sizeof(*mg));
 
 	if (mg != NULL)
 		map_groups__init(mg, machine);
-- 
2.22.0

[PATCH 2/2] perf unwind: fix libunwind when tid != pid

[John Keeping]

Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
leader") changed the recording side so that we no longer get mmap events
for threads other than the thread group leader.

When a file recorded after this change is loaded, the lack of mmap
records mean that unwinding is not set up for any other threads.

Following the rationale in that commit, move the libunwind fields into
struct map_groups and update the libunwind functions to take this
instead of the struct thread.  This is only required for
unwind__finish_access which must now be called from map_groups__delete
and the others are changed for symmetry.

Note that unwind__get_entries keeps the thread argument since it is
required for symbol lookup and the libdw unwind provider uses the thread
ID.

Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: John Keeping <john@metanate.com>
---
 tools/perf/util/map.c                    |  3 +-
 tools/perf/util/map_groups.h             |  4 +++
 tools/perf/util/thread.c                 |  7 ++---
 tools/perf/util/thread.h                 |  4 ---
 tools/perf/util/unwind-libunwind-local.c | 18 +++++------
 tools/perf/util/unwind-libunwind.c       | 40 ++++++++++--------------
 tools/perf/util/unwind.h                 | 25 ++++++++-------
 7 files changed, 48 insertions(+), 53 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 44b556812e4b..27b7b102e4a2 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -647,6 +647,7 @@ struct map_groups *map_groups__new(struct machine *machine)
 void map_groups__delete(struct map_groups *mg)
 {
 	map_groups__exit(mg);
+	unwind__finish_access(mg);
 	free(mg);
 }
 
@@ -887,7 +888,7 @@ int map_groups__clone(struct thread *thread, struct map_groups *parent)
 		if (new == NULL)
 			goto out_unlock;
 
-		err = unwind__prepare_access(thread, new, NULL);
+		err = unwind__prepare_access(mg, new, NULL);
 		if (err)
 			goto out_unlock;
 
diff --git a/tools/perf/util/map_groups.h b/tools/perf/util/map_groups.h
index 5f25efa6d6bc..77252e14008f 100644
--- a/tools/perf/util/map_groups.h
+++ b/tools/perf/util/map_groups.h
@@ -31,6 +31,10 @@ struct map_groups {
 	struct maps	 maps;
 	struct machine	 *machine;
 	refcount_t	 refcnt;
+#ifdef HAVE_LIBUNWIND_SUPPORT
+	void				*addr_space;
+	struct unwind_libunwind_ops	*unwind_libunwind_ops;
+#endif
 };
 
 #define KMAP_NAME_LEN 256
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 873ab505ca80..28e76d11f161 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -105,7 +105,6 @@ void thread__delete(struct thread *thread)
 	}
 	up_write(&thread->comm_lock);
 
-	unwind__finish_access(thread);
 	nsinfo__zput(thread->nsinfo);
 	srccode_state_free(&thread->srccode_state);
 
@@ -242,7 +241,7 @@ static int ____thread__set_comm(struct thread *thread, const char *str,
 		list_add(&new->list, &thread->comm_list);
 
 		if (exec)
-			unwind__flush_access(thread);
+			unwind__flush_access(thread->mg);
 	}
 
 	thread->comm_set = true;
@@ -322,7 +321,7 @@ int thread__insert_map(struct thread *thread, struct map *map)
 {
 	int ret;
 
-	ret = unwind__prepare_access(thread, map, NULL);
+	ret = unwind__prepare_access(thread->mg, map, NULL);
 	if (ret)
 		return ret;
 
@@ -342,7 +341,7 @@ static int __thread__prepare_access(struct thread *thread)
 	down_read(&maps->lock);
 
 	for (map = maps__first(maps); map; map = map__next(map)) {
-		err = unwind__prepare_access(thread, map, &initialized);
+		err = unwind__prepare_access(thread->mg, map, &initialized);
 		if (err || initialized)
 			break;
 	}
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index e97ef6977eb9..bf06113be4f3 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -44,10 +44,6 @@ struct thread {
 	struct thread_stack	*ts;
 	struct nsinfo		*nsinfo;
 	struct srccode_state	srccode_state;
-#ifdef HAVE_LIBUNWIND_SUPPORT
-	void				*addr_space;
-	struct unwind_libunwind_ops	*unwind_libunwind_ops;
-#endif
 	bool			filter;
 	int			filter_entry_depth;
 };
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 71a788921b62..ebdbb056510c 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -616,26 +616,26 @@ 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)
 {
-	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)
 {
-	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)
 {
-	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,
@@ -660,7 +660,7 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
 	 */
 	if (max_stack - 1 > 0) {
 		WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
-		addr_space = ui->thread->addr_space;
+		addr_space = ui->thread->mg->addr_space;
 
 		if (addr_space == NULL)
 			return -1;
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index c0811977d7d5..6499b22b158b 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -11,13 +11,13 @@ struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
 
-static void unwind__register_ops(struct thread *thread,
+static void unwind__register_ops(struct map_groups *mg,
 			  struct unwind_libunwind_ops *ops)
 {
-	thread->unwind_libunwind_ops = ops;
+	mg->unwind_libunwind_ops = ops;
 }
 
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized)
 {
 	const char *arch;
@@ -28,7 +28,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	if (!dwarf_callchain_users)
 		return 0;
 
-	if (thread->addr_space) {
+	if (mg->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
 			 map->dso->name);
 		if (initialized)
@@ -37,14 +37,14 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	}
 
 	/* env->arch is NULL for live-mode (i.e. perf top) */
-	if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+	if (!mg->machine->env || !mg->machine->env->arch)
 		goto out_register;
 
-	dso_type = dso__type(map->dso, thread->mg->machine);
+	dso_type = dso__type(map->dso, mg->machine);
 	if (dso_type == DSO__TYPE_UNKNOWN)
 		return 0;
 
-	arch = perf_env__arch(thread->mg->machine->env);
+	arch = perf_env__arch(mg->machine->env);
 
 	if (!strcmp(arch, "x86")) {
 		if (dso_type != DSO__TYPE_64BIT)
@@ -59,37 +59,31 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 		return 0;
 	}
 out_register:
-	unwind__register_ops(thread, ops);
+	unwind__register_ops(mg, ops);
 
-	err = thread->unwind_libunwind_ops->prepare_access(thread);
+	err = mg->unwind_libunwind_ops->prepare_access(mg);
 	if (initialized)
 		*initialized = err ? false : true;
 	return err;
 }
 
-void unwind__flush_access(struct thread *thread)
+void unwind__flush_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->flush_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
-void unwind__finish_access(struct thread *thread)
+void unwind__finish_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->finish_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->finish_access(mg);
 }
 
 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			 struct thread *thread,
 			 struct perf_sample *data, int max_stack)
 {
-	if (thread->unwind_libunwind_ops)
-		return thread->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+	if (thread->mg->unwind_libunwind_ops)
+		return thread->mg->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
 	return 0;
 }
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 8a44a1569a21..3a7d00c20d86 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 
 struct map;
+struct map_groups;
 struct perf_sample;
 struct symbol;
 struct thread;
@@ -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);
@@ -46,20 +47,20 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 #endif
 
 int LIBUNWIND__ARCH_REG_ID(int regnum);
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized);
-void unwind__flush_access(struct thread *thread);
-void unwind__finish_access(struct thread *thread);
+void unwind__flush_access(struct map_groups *mg);
+void unwind__finish_access(struct map_groups *mg);
 #else
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif
 #else
 static inline int
@@ -72,14 +73,14 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
 	return 0;
 }
 
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif /* HAVE_DWARF_UNWIND_SUPPORT */
 #endif /* __UNWIND_H */
-- 
2.22.0

Re: [PATCH 2/2] perf unwind: fix libunwind when tid != pid

[Jiri Olsa]

On Mon, Jul 29, 2019 at 06:24:30PM +0100, John Keeping wrote:
> Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
> leader") changed the recording side so that we no longer get mmap events
> for threads other than the thread group leader.
> 
> When a file recorded after this change is loaded, the lack of mmap
> records mean that unwinding is not set up for any other threads.

sry I dont' follow what's the problem here, could you please
describe the scenrio where the current code is failing in
more details

> 
> Following the rationale in that commit, move the libunwind fields into
> struct map_groups and update the libunwind functions to take this
> instead of the struct thread.  This is only required for
> unwind__finish_access which must now be called from map_groups__delete
> and the others are changed for symmetry.
> 
> Note that unwind__get_entries keeps the thread argument since it is
> required for symbol lookup and the libdw unwind provider uses the thread
> ID.

SNIP

> @@ -59,37 +59,31 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
>  		return 0;
>  	}
>  out_register:
> -	unwind__register_ops(thread, ops);
> +	unwind__register_ops(mg, ops);
>  
> -	err = thread->unwind_libunwind_ops->prepare_access(thread);
> +	err = mg->unwind_libunwind_ops->prepare_access(mg);
>  	if (initialized)
>  		*initialized = err ? false : true;
>  	return err;
>  }
>  
> -void unwind__flush_access(struct thread *thread)
> +void unwind__flush_access(struct map_groups *mg)
>  {
> -	if (!dwarf_callchain_users)
> -		return;

why did you remove this check?

> -
> -	if (thread->unwind_libunwind_ops)
> -		thread->unwind_libunwind_ops->flush_access(thread);
> +	if (mg->unwind_libunwind_ops)
> +		mg->unwind_libunwind_ops->flush_access(mg);
>  }
>  
> -void unwind__finish_access(struct thread *thread)
> +void unwind__finish_access(struct map_groups *mg)
>  {
> -	if (!dwarf_callchain_users)
> -		return;

why did you remove this check?

thanks,
jirka

Re: [PATCH 2/2] perf unwind: fix libunwind when tid != pid

[John Keeping]

On Fri, 2 Aug 2019 15:30:39 +0200
Jiri Olsa <jolsa@redhat.com> wrote:

> On Mon, Jul 29, 2019 at 06:24:30PM +0100, John Keeping wrote:
> > Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
> > leader") changed the recording side so that we no longer get mmap events
> > for threads other than the thread group leader.
> > 
> > When a file recorded after this change is loaded, the lack of mmap
> > records mean that unwinding is not set up for any other threads.  
> 
> sry I dont' follow what's the problem here, could you please
> describe the scenrio where the current code is failing in
> more details

With perf compiled to use libunwind, run:

	perf record --call-graph=dwarf -t $TID -- sleep 5
	perf report

If $TID is a process, then the output has the call graph, but if it's a
secondary thread then it is as if --no-call-graph was specified.

> > 
> > Following the rationale in that commit, move the libunwind fields into
> > struct map_groups and update the libunwind functions to take this
> > instead of the struct thread.  This is only required for
> > unwind__finish_access which must now be called from map_groups__delete
> > and the others are changed for symmetry.
> > 
> > Note that unwind__get_entries keeps the thread argument since it is
> > required for symbol lookup and the libdw unwind provider uses the thread
> > ID.  
> 
> SNIP
> 
> > @@ -59,37 +59,31 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
> >  		return 0;
> >  	}
> >  out_register:
> > -	unwind__register_ops(thread, ops);
> > +	unwind__register_ops(mg, ops);
> >  
> > -	err = thread->unwind_libunwind_ops->prepare_access(thread);
> > +	err = mg->unwind_libunwind_ops->prepare_access(mg);
> >  	if (initialized)
> >  		*initialized = err ? false : true;
> >  	return err;
> >  }
> >  
> > -void unwind__flush_access(struct thread *thread)
> > +void unwind__flush_access(struct map_groups *mg)
> >  {
> > -	if (!dwarf_callchain_users)
> > -		return;  
> 
> why did you remove this check?

I don't think there is any way for unwind_libunwind_ops to be set if
!dwarf_callchain_users so this is redundant given the following
condition.

But this should probably be a separate patch.

> > -
> > -	if (thread->unwind_libunwind_ops)
> > -		thread->unwind_libunwind_ops->flush_access(thread);
> > +	if (mg->unwind_libunwind_ops)
> > +		mg->unwind_libunwind_ops->flush_access(mg);
> >  }
> >  
> > -void unwind__finish_access(struct thread *thread)
> > +void unwind__finish_access(struct map_groups *mg)
> >  {
> > -	if (!dwarf_callchain_users)
> > -		return;  
> 
> why did you remove this check?

Likewise.


Regards,
John

[PATCH v2 1/3] perf map: use zalloc for map_groups

[John Keeping]

In the next commit we will add new fields to map_groups and we need
these to be null if no value is assigned.  The simplest way to achieve
this is to request zeroed memory from the allocator.

Signed-off-by: John Keeping <john@metanate.com>
---
Unchanged in v2
---
 tools/perf/util/map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 668410b1d426..44b556812e4b 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -636,7 +636,7 @@ bool map_groups__empty(struct map_groups *mg)
 
 struct map_groups *map_groups__new(struct machine *machine)
 {
-	struct map_groups *mg = malloc(sizeof(*mg));
+	struct map_groups *mg = zalloc(sizeof(*mg));
 
 	if (mg != NULL)
 		map_groups__init(mg, machine);
-- 
2.22.0

[PATCH v2 2/3] perf unwind: fix libunwind when tid != pid

[John Keeping]

Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
leader") changed the recording side so that we no longer get mmap events
for threads other than the thread group leader (when synthesising these
events for threads which exist before perf is started).

When a file recorded after this change is loaded, the lack of mmap
records mean that unwinding is not set up for any other threads.

This can be seen in a simple record/report scenario:

	perf record --call-graph=dwarf -t $TID
	perf report

If $TID is a process ID then the report will show call graphs, but if
$TID is a secondary thread the output is as if --call-graph=none was
specified.

Following the rationale in that commit, move the libunwind fields into
struct map_groups and update the libunwind functions to take this
instead of the struct thread.  This is only required for
unwind__finish_access which must now be called from map_groups__delete
and the others are changed for symmetry.

Note that unwind__get_entries keeps the thread argument since it is
required for symbol lookup and the libdw unwind provider uses the thread
ID.

Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: John Keeping <john@metanate.com>
---
v2:
- Remove unrelated change that has moved to the next patch
- Improve commit message to describe a scenario that shows the bug
---
 tools/perf/util/map.c                    |  3 ++-
 tools/perf/util/map_groups.h             |  4 +++
 tools/perf/util/thread.c                 |  7 +++--
 tools/perf/util/thread.h                 |  4 ---
 tools/perf/util/unwind-libunwind-local.c | 18 ++++++-------
 tools/perf/util/unwind-libunwind.c       | 34 ++++++++++++------------
 tools/perf/util/unwind.h                 | 25 ++++++++---------
 7 files changed, 48 insertions(+), 47 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 44b556812e4b..27b7b102e4a2 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -647,6 +647,7 @@ struct map_groups *map_groups__new(struct machine *machine)
 void map_groups__delete(struct map_groups *mg)
 {
 	map_groups__exit(mg);
+	unwind__finish_access(mg);
 	free(mg);
 }
 
@@ -887,7 +888,7 @@ int map_groups__clone(struct thread *thread, struct map_groups *parent)
 		if (new == NULL)
 			goto out_unlock;
 
-		err = unwind__prepare_access(thread, new, NULL);
+		err = unwind__prepare_access(mg, new, NULL);
 		if (err)
 			goto out_unlock;
 
diff --git a/tools/perf/util/map_groups.h b/tools/perf/util/map_groups.h
index 5f25efa6d6bc..77252e14008f 100644
--- a/tools/perf/util/map_groups.h
+++ b/tools/perf/util/map_groups.h
@@ -31,6 +31,10 @@ struct map_groups {
 	struct maps	 maps;
 	struct machine	 *machine;
 	refcount_t	 refcnt;
+#ifdef HAVE_LIBUNWIND_SUPPORT
+	void				*addr_space;
+	struct unwind_libunwind_ops	*unwind_libunwind_ops;
+#endif
 };
 
 #define KMAP_NAME_LEN 256
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 590793cc5142..bbf7816cba31 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -105,7 +105,6 @@ void thread__delete(struct thread *thread)
 	}
 	up_write(&thread->comm_lock);
 
-	unwind__finish_access(thread);
 	nsinfo__zput(thread->nsinfo);
 	srccode_state_free(&thread->srccode_state);
 
@@ -252,7 +251,7 @@ static int ____thread__set_comm(struct thread *thread, const char *str,
 		list_add(&new->list, &thread->comm_list);
 
 		if (exec)
-			unwind__flush_access(thread);
+			unwind__flush_access(thread->mg);
 	}
 
 	thread->comm_set = true;
@@ -332,7 +331,7 @@ int thread__insert_map(struct thread *thread, struct map *map)
 {
 	int ret;
 
-	ret = unwind__prepare_access(thread, map, NULL);
+	ret = unwind__prepare_access(thread->mg, map, NULL);
 	if (ret)
 		return ret;
 
@@ -352,7 +351,7 @@ static int __thread__prepare_access(struct thread *thread)
 	down_read(&maps->lock);
 
 	for (map = maps__first(maps); map; map = map__next(map)) {
-		err = unwind__prepare_access(thread, map, &initialized);
+		err = unwind__prepare_access(thread->mg, map, &initialized);
 		if (err || initialized)
 			break;
 	}
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index e97ef6977eb9..bf06113be4f3 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -44,10 +44,6 @@ struct thread {
 	struct thread_stack	*ts;
 	struct nsinfo		*nsinfo;
 	struct srccode_state	srccode_state;
-#ifdef HAVE_LIBUNWIND_SUPPORT
-	void				*addr_space;
-	struct unwind_libunwind_ops	*unwind_libunwind_ops;
-#endif
 	bool			filter;
 	int			filter_entry_depth;
 };
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 71a788921b62..ebdbb056510c 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -616,26 +616,26 @@ 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)
 {
-	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)
 {
-	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)
 {
-	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,
@@ -660,7 +660,7 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
 	 */
 	if (max_stack - 1 > 0) {
 		WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
-		addr_space = ui->thread->addr_space;
+		addr_space = ui->thread->mg->addr_space;
 
 		if (addr_space == NULL)
 			return -1;
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index c0811977d7d5..b843f9d0a9ea 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -11,13 +11,13 @@ struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
 
-static void unwind__register_ops(struct thread *thread,
+static void unwind__register_ops(struct map_groups *mg,
 			  struct unwind_libunwind_ops *ops)
 {
-	thread->unwind_libunwind_ops = ops;
+	mg->unwind_libunwind_ops = ops;
 }
 
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized)
 {
 	const char *arch;
@@ -28,7 +28,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	if (!dwarf_callchain_users)
 		return 0;
 
-	if (thread->addr_space) {
+	if (mg->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
 			 map->dso->name);
 		if (initialized)
@@ -37,14 +37,14 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	}
 
 	/* env->arch is NULL for live-mode (i.e. perf top) */
-	if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+	if (!mg->machine->env || !mg->machine->env->arch)
 		goto out_register;
 
-	dso_type = dso__type(map->dso, thread->mg->machine);
+	dso_type = dso__type(map->dso, mg->machine);
 	if (dso_type == DSO__TYPE_UNKNOWN)
 		return 0;
 
-	arch = perf_env__arch(thread->mg->machine->env);
+	arch = perf_env__arch(mg->machine->env);
 
 	if (!strcmp(arch, "x86")) {
 		if (dso_type != DSO__TYPE_64BIT)
@@ -59,37 +59,37 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 		return 0;
 	}
 out_register:
-	unwind__register_ops(thread, ops);
+	unwind__register_ops(mg, ops);
 
-	err = thread->unwind_libunwind_ops->prepare_access(thread);
+	err = mg->unwind_libunwind_ops->prepare_access(mg);
 	if (initialized)
 		*initialized = err ? false : true;
 	return err;
 }
 
-void unwind__flush_access(struct thread *thread)
+void unwind__flush_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->flush_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
-void unwind__finish_access(struct thread *thread)
+void unwind__finish_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->finish_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->finish_access(mg);
 }
 
 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			 struct thread *thread,
 			 struct perf_sample *data, int max_stack)
 {
-	if (thread->unwind_libunwind_ops)
-		return thread->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+	if (thread->mg->unwind_libunwind_ops)
+		return thread->mg->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
 	return 0;
 }
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 8a44a1569a21..3a7d00c20d86 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 
 struct map;
+struct map_groups;
 struct perf_sample;
 struct symbol;
 struct thread;
@@ -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);
@@ -46,20 +47,20 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 #endif
 
 int LIBUNWIND__ARCH_REG_ID(int regnum);
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized);
-void unwind__flush_access(struct thread *thread);
-void unwind__finish_access(struct thread *thread);
+void unwind__flush_access(struct map_groups *mg);
+void unwind__finish_access(struct map_groups *mg);
 #else
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif
 #else
 static inline int
@@ -72,14 +73,14 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
 	return 0;
 }
 
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif /* HAVE_DWARF_UNWIND_SUPPORT */
 #endif /* __UNWIND_H */
-- 
2.22.0

[PATCH v2 3/3] perf unwind: remove unnecessary test

[John Keeping]

If dwarf_callchain_users is false, then unwind__prepare_access() will
not set unwind_libunwind_ops so the remaining test here is sufficient.

Signed-off-by: John Keeping <john@metanate.com>
---
v2: new patch split out from patch 2
---
 tools/perf/util/unwind-libunwind.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index b843f9d0a9ea..6499b22b158b 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -69,18 +69,12 @@ int unwind__prepare_access(struct map_groups *mg, struct map *map,
 
 void unwind__flush_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
 	if (mg->unwind_libunwind_ops)
 		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
 void unwind__finish_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
 	if (mg->unwind_libunwind_ops)
 		mg->unwind_libunwind_ops->finish_access(mg);
 }
-- 
2.22.0

Re: [PATCH v2 2/3] perf unwind: fix libunwind when tid != pid

[Jiri Olsa]

On Thu, Aug 15, 2019 at 11:01:45AM +0100, John Keeping wrote:
> Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
> leader") changed the recording side so that we no longer get mmap events
> for threads other than the thread group leader (when synthesising these
> events for threads which exist before perf is started).
> 
> When a file recorded after this change is loaded, the lack of mmap
> records mean that unwinding is not set up for any other threads.
> 
> This can be seen in a simple record/report scenario:
> 
> 	perf record --call-graph=dwarf -t $TID
> 	perf report
> 
> If $TID is a process ID then the report will show call graphs, but if
> $TID is a secondary thread the output is as if --call-graph=none was
> specified.

great, mucch clearler now

> 
> Following the rationale in that commit, move the libunwind fields into
> struct map_groups and update the libunwind functions to take this
> instead of the struct thread.  This is only required for
> unwind__finish_access which must now be called from map_groups__delete
> and the others are changed for symmetry.
> 
> Note that unwind__get_entries keeps the thread argument since it is
> required for symbol lookup and the libdw unwind provider uses the thread
> ID.
> 
> Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")

for all 3 patches

Reviewed-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

Re: [PATCH v2 2/3] perf unwind: fix libunwind when tid != pid

[Arnaldo Carvalho de Melo]

Em Thu, Aug 15, 2019 at 04:10:35PM +0200, Jiri Olsa escreveu:
> On Thu, Aug 15, 2019 at 11:01:45AM +0100, John Keeping wrote:
> > Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
> > leader") changed the recording side so that we no longer get mmap events
> > for threads other than the thread group leader (when synthesising these
> > events for threads which exist before perf is started).
> > 
> > When a file recorded after this change is loaded, the lack of mmap
> > records mean that unwinding is not set up for any other threads.
> > 
> > This can be seen in a simple record/report scenario:
> > 
> > 	perf record --call-graph=dwarf -t $TID
> > 	perf report
> > 
> > If $TID is a process ID then the report will show call graphs, but if
> > $TID is a secondary thread the output is as if --call-graph=none was
> > specified.
> 
> great, mucch clearler now
> 
> > 
> > Following the rationale in that commit, move the libunwind fields into
> > struct map_groups and update the libunwind functions to take this
> > instead of the struct thread.  This is only required for
> > unwind__finish_access which must now be called from map_groups__delete
> > and the others are changed for symmetry.
> > 
> > Note that unwind__get_entries keeps the thread argument since it is
> > required for symbol lookup and the libdw unwind provider uses the thread
> > ID.
> > 
> > Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
> 
> for all 3 patches
> 
> Reviewed-by: Jiri Olsa <jolsa@kernel.org>


Thanks, applied.

- Arnaldo

[tip:perf/core] perf map: Use zalloc for map_groups

[tip-bot for John Keeping]

Commit-ID:  ab6cd0e5276e24403751e0b3b8ed807738a8571f
Gitweb:     https://git.kernel.org/tip/ab6cd0e5276e24403751e0b3b8ed807738a8571f
Author:     John Keeping <john@metanate.com>
AuthorDate: Thu, 15 Aug 2019 11:01:44 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 16 Aug 2019 12:25:23 -0300

perf map: Use zalloc for map_groups

In the next commit we will add new fields to map_groups and we need
these to be null if no value is assigned.  The simplest way to achieve
this is to request zeroed memory from the allocator.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: john keeping <john@metanate.com>
Link: http://lkml.kernel.org/r/20190815100146.28842-1-john@metanate.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 668410b1d426..44b556812e4b 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -636,7 +636,7 @@ bool map_groups__empty(struct map_groups *mg)
 
 struct map_groups *map_groups__new(struct machine *machine)
 {
-	struct map_groups *mg = malloc(sizeof(*mg));
+	struct map_groups *mg = zalloc(sizeof(*mg));
 
 	if (mg != NULL)
 		map_groups__init(mg, machine);

[tip:perf/core] perf unwind: Fix libunwind when tid != pid

[tip-bot for John Keeping]

Commit-ID:  e8ba2906f6b9054102ad035ac9cafad9d4168589
Gitweb:     https://git.kernel.org/tip/e8ba2906f6b9054102ad035ac9cafad9d4168589
Author:     John Keeping <john@metanate.com>
AuthorDate: Thu, 15 Aug 2019 11:01:45 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 16 Aug 2019 12:25:57 -0300

perf unwind: Fix libunwind when tid != pid

Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
leader") changed the recording side so that we no longer get mmap events
for threads other than the thread group leader (when synthesising these
events for threads which exist before perf is started).

When a file recorded after this change is loaded, the lack of mmap
records mean that unwinding is not set up for any other threads.

This can be seen in a simple record/report scenario:

	perf record --call-graph=dwarf -t $TID
	perf report

If $TID is a process ID then the report will show call graphs, but if
$TID is a secondary thread the output is as if --call-graph=none was
specified.

Following the rationale in that commit, move the libunwind fields into
struct map_groups and update the libunwind functions to take this
instead of the struct thread.  This is only required for
unwind__finish_access which must now be called from map_groups__delete
and the others are changed for symmetry.

Note that unwind__get_entries keeps the thread argument since it is
required for symbol lookup and the libdw unwind provider uses the thread
ID.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
Link: http://lkml.kernel.org/r/20190815100146.28842-2-john@metanate.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/map.c                    |  3 ++-
 tools/perf/util/map_groups.h             |  4 ++++
 tools/perf/util/thread.c                 |  7 +++----
 tools/perf/util/thread.h                 |  4 ----
 tools/perf/util/unwind-libunwind-local.c | 18 ++++++++---------
 tools/perf/util/unwind-libunwind.c       | 34 ++++++++++++++++----------------
 tools/perf/util/unwind.h                 | 25 ++++++++++++-----------
 7 files changed, 48 insertions(+), 47 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 44b556812e4b..27b7b102e4a2 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -647,6 +647,7 @@ struct map_groups *map_groups__new(struct machine *machine)
 void map_groups__delete(struct map_groups *mg)
 {
 	map_groups__exit(mg);
+	unwind__finish_access(mg);
 	free(mg);
 }
 
@@ -887,7 +888,7 @@ int map_groups__clone(struct thread *thread, struct map_groups *parent)
 		if (new == NULL)
 			goto out_unlock;
 
-		err = unwind__prepare_access(thread, new, NULL);
+		err = unwind__prepare_access(mg, new, NULL);
 		if (err)
 			goto out_unlock;
 
diff --git a/tools/perf/util/map_groups.h b/tools/perf/util/map_groups.h
index 5f25efa6d6bc..77252e14008f 100644
--- a/tools/perf/util/map_groups.h
+++ b/tools/perf/util/map_groups.h
@@ -31,6 +31,10 @@ struct map_groups {
 	struct maps	 maps;
 	struct machine	 *machine;
 	refcount_t	 refcnt;
+#ifdef HAVE_LIBUNWIND_SUPPORT
+	void				*addr_space;
+	struct unwind_libunwind_ops	*unwind_libunwind_ops;
+#endif
 };
 
 #define KMAP_NAME_LEN 256
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 590793cc5142..bbf7816cba31 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -105,7 +105,6 @@ void thread__delete(struct thread *thread)
 	}
 	up_write(&thread->comm_lock);
 
-	unwind__finish_access(thread);
 	nsinfo__zput(thread->nsinfo);
 	srccode_state_free(&thread->srccode_state);
 
@@ -252,7 +251,7 @@ static int ____thread__set_comm(struct thread *thread, const char *str,
 		list_add(&new->list, &thread->comm_list);
 
 		if (exec)
-			unwind__flush_access(thread);
+			unwind__flush_access(thread->mg);
 	}
 
 	thread->comm_set = true;
@@ -332,7 +331,7 @@ int thread__insert_map(struct thread *thread, struct map *map)
 {
 	int ret;
 
-	ret = unwind__prepare_access(thread, map, NULL);
+	ret = unwind__prepare_access(thread->mg, map, NULL);
 	if (ret)
 		return ret;
 
@@ -352,7 +351,7 @@ static int __thread__prepare_access(struct thread *thread)
 	down_read(&maps->lock);
 
 	for (map = maps__first(maps); map; map = map__next(map)) {
-		err = unwind__prepare_access(thread, map, &initialized);
+		err = unwind__prepare_access(thread->mg, map, &initialized);
 		if (err || initialized)
 			break;
 	}
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index e97ef6977eb9..bf06113be4f3 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -44,10 +44,6 @@ struct thread {
 	struct thread_stack	*ts;
 	struct nsinfo		*nsinfo;
 	struct srccode_state	srccode_state;
-#ifdef HAVE_LIBUNWIND_SUPPORT
-	void				*addr_space;
-	struct unwind_libunwind_ops	*unwind_libunwind_ops;
-#endif
 	bool			filter;
 	int			filter_entry_depth;
 };
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 71a788921b62..ebdbb056510c 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -616,26 +616,26 @@ 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)
 {
-	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)
 {
-	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)
 {
-	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,
@@ -660,7 +660,7 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
 	 */
 	if (max_stack - 1 > 0) {
 		WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
-		addr_space = ui->thread->addr_space;
+		addr_space = ui->thread->mg->addr_space;
 
 		if (addr_space == NULL)
 			return -1;
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index c0811977d7d5..b843f9d0a9ea 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -11,13 +11,13 @@ struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
 
-static void unwind__register_ops(struct thread *thread,
+static void unwind__register_ops(struct map_groups *mg,
 			  struct unwind_libunwind_ops *ops)
 {
-	thread->unwind_libunwind_ops = ops;
+	mg->unwind_libunwind_ops = ops;
 }
 
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized)
 {
 	const char *arch;
@@ -28,7 +28,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	if (!dwarf_callchain_users)
 		return 0;
 
-	if (thread->addr_space) {
+	if (mg->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
 			 map->dso->name);
 		if (initialized)
@@ -37,14 +37,14 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	}
 
 	/* env->arch is NULL for live-mode (i.e. perf top) */
-	if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+	if (!mg->machine->env || !mg->machine->env->arch)
 		goto out_register;
 
-	dso_type = dso__type(map->dso, thread->mg->machine);
+	dso_type = dso__type(map->dso, mg->machine);
 	if (dso_type == DSO__TYPE_UNKNOWN)
 		return 0;
 
-	arch = perf_env__arch(thread->mg->machine->env);
+	arch = perf_env__arch(mg->machine->env);
 
 	if (!strcmp(arch, "x86")) {
 		if (dso_type != DSO__TYPE_64BIT)
@@ -59,37 +59,37 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 		return 0;
 	}
 out_register:
-	unwind__register_ops(thread, ops);
+	unwind__register_ops(mg, ops);
 
-	err = thread->unwind_libunwind_ops->prepare_access(thread);
+	err = mg->unwind_libunwind_ops->prepare_access(mg);
 	if (initialized)
 		*initialized = err ? false : true;
 	return err;
 }
 
-void unwind__flush_access(struct thread *thread)
+void unwind__flush_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->flush_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
-void unwind__finish_access(struct thread *thread)
+void unwind__finish_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->finish_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->finish_access(mg);
 }
 
 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			 struct thread *thread,
 			 struct perf_sample *data, int max_stack)
 {
-	if (thread->unwind_libunwind_ops)
-		return thread->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+	if (thread->mg->unwind_libunwind_ops)
+		return thread->mg->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
 	return 0;
 }
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 8a44a1569a21..3a7d00c20d86 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 
 struct map;
+struct map_groups;
 struct perf_sample;
 struct symbol;
 struct thread;
@@ -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);
@@ -46,20 +47,20 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 #endif
 
 int LIBUNWIND__ARCH_REG_ID(int regnum);
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized);
-void unwind__flush_access(struct thread *thread);
-void unwind__finish_access(struct thread *thread);
+void unwind__flush_access(struct map_groups *mg);
+void unwind__finish_access(struct map_groups *mg);
 #else
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif
 #else
 static inline int
@@ -72,14 +73,14 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
 	return 0;
 }
 
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+static inline int unwind__prepare_access(struct map_groups *mg __maybe_unused,
 					 struct map *map __maybe_unused,
 					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
 
-static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
-static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void unwind__flush_access(struct map_groups *mg __maybe_unused) {}
+static inline void unwind__finish_access(struct map_groups *mg __maybe_unused) {}
 #endif /* HAVE_DWARF_UNWIND_SUPPORT */
 #endif /* __UNWIND_H */

[tip:perf/core] perf unwind: Remove unnecessary test

[tip-bot for John Keeping]

Commit-ID:  e2736219e6ca3117e10651e215b96d66775220da
Gitweb:     https://git.kernel.org/tip/e2736219e6ca3117e10651e215b96d66775220da
Author:     John Keeping <john@metanate.com>
AuthorDate: Thu, 15 Aug 2019 11:01:46 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 16 Aug 2019 12:30:14 -0300

perf unwind: Remove unnecessary test

If dwarf_callchain_users is false, then unwind__prepare_access() will
not set unwind_libunwind_ops so the remaining test here is sufficient.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: john keeping <john@metanate.com>
Link: http://lkml.kernel.org/r/20190815100146.28842-3-john@metanate.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/unwind-libunwind.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index b843f9d0a9ea..6499b22b158b 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -69,18 +69,12 @@ out_register:
 
 void unwind__flush_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
 	if (mg->unwind_libunwind_ops)
 		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
 void unwind__finish_access(struct map_groups *mg)
 {
-	if (!dwarf_callchain_users)
-		return;
-
 	if (mg->unwind_libunwind_ops)
 		mg->unwind_libunwind_ops->finish_access(mg);
 }