Commit e266a753 authored Nov 13, 2015 by Adrian Hunter Committed by Arnaldo Carvalho de Melo Nov 13, 2015

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



Commit 4598a0a6 ("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: 4598a0a6 ("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>

parent 2059fc7a

tools/perf/util/dso.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -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);

tools/perf/util/dso.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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 {

tools/perf/util/machine.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}

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