perf symbols: Fix dso lookup by long name and missing buildids

Commit 4598a0a6d22f ("perf symbols: Improve DSO long names lookup speed
with rbtree") Added a tree to lookup dsos by long name.  That tree gets
corrupted whenever a dso long name is changed because the tree is not
updated.

One effect of that is buildid-list does not work with the 'with-hits'
option because dso lookup fails and results in two structs for the same
dso.  The first has the buildid but no hits, the second has hits but no
buildid. e.g.

Before:

  $ tools/perf/perf record ls
  arch     certs    CREDITS  Documentation  firmware  include
  ipc      Kconfig  lib      Makefile       net       REPORTING-BUGS
  scripts  sound    usr      block          COPYING   crypto
  drivers  fs       init     Kbuild         kernel    MAINTAINERS
  mm       README   samples  security       tools     virt
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.012 MB perf.data (11 samples) ]
  $ tools/perf/perf buildid-list
  574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
  30c94dc66a1fe95180c3d68d2b89e576d5ae213c /lib/x86_64-linux-gnu/libc-2.19.so
  $ tools/perf/perf buildid-list -H
  574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
  0000000000000000000000000000000000000000 /lib/x86_64-linux-gnu/libc-2.19.so

After:

  $ tools/perf/perf buildid-list -H
  574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
  30c94dc66a1fe95180c3d68d2b89e576d5ae213c /lib/x86_64-linux-gnu/libc-2.19.so

The fix is to record the root of the tree on the dso so that
dso__set_long_name() can update the tree when the long name changes.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Fixes: 4598a0a6d22f ("perf symbols: Improve DSO long names lookup speed with rbtree")
Link: http://lkml.kernel.org/r/1447408112-1920-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 7c0c08386a1d9d6fb5e8cba6c838e5c3c1949bd7..425df5c86c9c9acc8a1cb9dd87540f677e885c5e 100644 (file)
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -933,6 +933,7 @@ static struct dso *__dso__findlink_by_longname(struct rb_root *root,
                /* Add new node and rebalance tree */
                rb_link_node(&dso->rb_node, parent, p);
                rb_insert_color(&dso->rb_node, root);
+               dso->root = root;
        }
        return NULL;
 }
@@ -945,15 +946,30 @@ static inline struct dso *__dso__find_by_longname(struct rb_root *root,
 
 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
 {
+       struct rb_root *root = dso->root;
+
        if (name == NULL)
                return;
 
        if (dso->long_name_allocated)
                free((char *)dso->long_name);
 
+       if (root) {
+               rb_erase(&dso->rb_node, root);
+               /*
+                * __dso__findlink_by_longname() isn't guaranteed to add it
+                * back, so a clean removal is required here.
+                */
+               RB_CLEAR_NODE(&dso->rb_node);
+               dso->root = NULL;
+       }
+
        dso->long_name           = name;
        dso->long_name_len       = strlen(name);
        dso->long_name_allocated = name_allocated;
+
+       if (root)
+               __dso__findlink_by_longname(root, dso, NULL);
 }
 
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
@@ -1046,6 +1062,7 @@ struct dso *dso__new(const char *name)
                dso->kernel = DSO_TYPE_USER;
                dso->needs_swap = DSO_SWAP__UNSET;
                RB_CLEAR_NODE(&dso->rb_node);
+               dso->root = NULL;
                INIT_LIST_HEAD(&dso->node);
                INIT_LIST_HEAD(&dso->data.open_entry);
                pthread_mutex_init(&dso->lock, NULL);

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index fc8db9c764acace9c905d5429d999e9c1401d0c4..45ec4d0a50eda2f8c3b3bc700e573ce89ed58fc8 100644 (file)
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -135,6 +135,7 @@ struct dso {
        pthread_mutex_t  lock;
        struct list_head node;
        struct rb_node   rb_node;       /* rbtree node sorted by long name */
+       struct rb_root   *root;         /* root of rbtree that rb_node is in */
        struct rb_root   symbols[MAP__NR_TYPES];
        struct rb_root   symbol_names[MAP__NR_TYPES];
        struct {

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 5ef90be2a2497a05731a5fb8d24af33a192f2011..8b303ff20289a8ffb4baff9e29292dd47e9068eb 100644 (file)
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -91,6 +91,7 @@ static void dsos__purge(struct dsos *dsos)
 
        list_for_each_entry_safe(pos, n, &dsos->head, node) {
                RB_CLEAR_NODE(&pos->rb_node);
+               pos->root = NULL;
                list_del_init(&pos->node);
                dso__put(pos);
        }