linux/tools/perf/util/dsos.c
Ravi Bangoria 0d33b34352 perf dso: Fix dso comparison
Perf gets dso details from two different sources. 1st, from builid
headers in perf.data and 2nd from MMAP2 samples. Dso from buildid
header does not have dso_id detail. And dso from MMAP2 samples does
not have buildid information. If detail of the same dso is present
at both the places, filename is common.

Previously, __dsos__findnew_link_by_longname_id() used to compare only
long or short names, but Commit 0e3149f86b ("perf dso: Move dso_id
from 'struct map' to 'struct dso'") also added a dso_id comparison.
Because of that, now perf is creating two different dso objects of the
same file, one from buildid header (with dso_id but without buildid)
and second from MMAP2 sample (with buildid but without dso_id).

This is causing issues with archive, buildid-list etc subcommands. Fix
this by comparing dso_id only when it's present. And incase dso is
present in 'dsos' list without dso_id, inject dso_id detail as well.

Before:

  $ sudo ./perf buildid-list -H
  0000000000000000000000000000000000000000 /usr/bin/ls
  0000000000000000000000000000000000000000 /usr/lib64/ld-2.30.so
  0000000000000000000000000000000000000000 /usr/lib64/libc-2.30.so

  $ ./perf archive
  perf archive: no build-ids found

After:

  $ ./perf buildid-list -H
  b6b1291d0cead046ed0fa5734037fa87a579adee /usr/bin/ls
  641f0c90cfa15779352f12c0ec3c7a2b2b6f41e8 /usr/lib64/ld-2.30.so
  675ace3ca07a0b863df01f461a7b0984c65c8b37 /usr/lib64/libc-2.30.so

  $ ./perf archive
  Now please run:

  $ tar xvf perf.data.tar.bz2 -C ~/.debug

  wherever you need to run 'perf report' on.

Committer notes:

Renamed is_empty_dso_id() to dso_id__empty() and inject_dso_id() to
dso__inject_id() to keep namespacing consistent.

Fixes: 0e3149f86b ("perf dso: Move dso_id from 'struct map' to 'struct dso'")
Reported-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20200324042424.68366-1-ravi.bangoria@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-03-24 10:57:38 -03:00

310 lines
7.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "debug.h"
#include "dsos.h"
#include "dso.h"
#include "vdso.h"
#include "namespaces.h"
#include <libgen.h>
#include <stdlib.h>
#include <string.h>
#include <symbol.h> // filename__read_build_id
static int __dso_id__cmp(struct dso_id *a, struct dso_id *b)
{
if (a->maj > b->maj) return -1;
if (a->maj < b->maj) return 1;
if (a->min > b->min) return -1;
if (a->min < b->min) return 1;
if (a->ino > b->ino) return -1;
if (a->ino < b->ino) return 1;
if (a->ino_generation > b->ino_generation) return -1;
if (a->ino_generation < b->ino_generation) return 1;
return 0;
}
static bool dso_id__empty(struct dso_id *id)
{
if (!id)
return true;
return !id->maj && !id->min && !id->ino && !id->ino_generation;
}
static void dso__inject_id(struct dso *dso, struct dso_id *id)
{
dso->id.maj = id->maj;
dso->id.min = id->min;
dso->id.ino = id->ino;
dso->id.ino_generation = id->ino_generation;
}
static int dso_id__cmp(struct dso_id *a, struct dso_id *b)
{
/*
* The second is always dso->id, so zeroes if not set, assume passing
* NULL for a means a zeroed id
*/
if (dso_id__empty(a) || dso_id__empty(b))
return 0;
return __dso_id__cmp(a, b);
}
int dso__cmp_id(struct dso *a, struct dso *b)
{
return __dso_id__cmp(&a->id, &b->id);
}
bool __dsos__read_build_ids(struct list_head *head, bool with_hits)
{
bool have_build_id = false;
struct dso *pos;
struct nscookie nsc;
list_for_each_entry(pos, head, node) {
if (with_hits && !pos->hit && !dso__is_vdso(pos))
continue;
if (pos->has_build_id) {
have_build_id = true;
continue;
}
nsinfo__mountns_enter(pos->nsinfo, &nsc);
if (filename__read_build_id(pos->long_name, pos->build_id,
sizeof(pos->build_id)) > 0) {
have_build_id = true;
pos->has_build_id = true;
}
nsinfo__mountns_exit(&nsc);
}
return have_build_id;
}
static int __dso__cmp_long_name(const char *long_name, struct dso_id *id, struct dso *b)
{
int rc = strcmp(long_name, b->long_name);
return rc ?: dso_id__cmp(id, &b->id);
}
static int __dso__cmp_short_name(const char *short_name, struct dso_id *id, struct dso *b)
{
int rc = strcmp(short_name, b->short_name);
return rc ?: dso_id__cmp(id, &b->id);
}
static int dso__cmp_short_name(struct dso *a, struct dso *b)
{
return __dso__cmp_short_name(a->short_name, &a->id, b);
}
/*
* Find a matching entry and/or link current entry to RB tree.
* Either one of the dso or name parameter must be non-NULL or the
* function will not work.
*/
struct dso *__dsos__findnew_link_by_longname_id(struct rb_root *root, struct dso *dso,
const char *name, struct dso_id *id)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
if (!name)
name = dso->long_name;
/*
* Find node with the matching name
*/
while (*p) {
struct dso *this = rb_entry(*p, struct dso, rb_node);
int rc = __dso__cmp_long_name(name, id, this);
parent = *p;
if (rc == 0) {
/*
* In case the new DSO is a duplicate of an existing
* one, print a one-time warning & put the new entry
* at the end of the list of duplicates.
*/
if (!dso || (dso == this))
return this; /* Find matching dso */
/*
* The core kernel DSOs may have duplicated long name.
* In this case, the short name should be different.
* Comparing the short names to differentiate the DSOs.
*/
rc = dso__cmp_short_name(dso, this);
if (rc == 0) {
pr_err("Duplicated dso name: %s\n", name);
return NULL;
}
}
if (rc < 0)
p = &parent->rb_left;
else
p = &parent->rb_right;
}
if (dso) {
/* 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;
}
void __dsos__add(struct dsos *dsos, struct dso *dso)
{
list_add_tail(&dso->node, &dsos->head);
__dsos__findnew_link_by_longname_id(&dsos->root, dso, NULL, &dso->id);
/*
* It is now in the linked list, grab a reference, then garbage collect
* this when needing memory, by looking at LRU dso instances in the
* list with atomic_read(&dso->refcnt) == 1, i.e. no references
* anywhere besides the one for the list, do, under a lock for the
* list: remove it from the list, then a dso__put(), that probably will
* be the last and will then call dso__delete(), end of life.
*
* That, or at the end of the 'struct machine' lifetime, when all
* 'struct dso' instances will be removed from the list, in
* dsos__exit(), if they have no other reference from some other data
* structure.
*
* E.g.: after processing a 'perf.data' file and storing references
* to objects instantiated while processing events, we will have
* references to the 'thread', 'map', 'dso' structs all from 'struct
* hist_entry' instances, but we may not need anything not referenced,
* so we might as well call machines__exit()/machines__delete() and
* garbage collect it.
*/
dso__get(dso);
}
void dsos__add(struct dsos *dsos, struct dso *dso)
{
down_write(&dsos->lock);
__dsos__add(dsos, dso);
up_write(&dsos->lock);
}
static struct dso *__dsos__findnew_by_longname_id(struct rb_root *root, const char *name, struct dso_id *id)
{
return __dsos__findnew_link_by_longname_id(root, NULL, name, id);
}
static struct dso *__dsos__find_id(struct dsos *dsos, const char *name, struct dso_id *id, bool cmp_short)
{
struct dso *pos;
if (cmp_short) {
list_for_each_entry(pos, &dsos->head, node)
if (__dso__cmp_short_name(name, id, pos) == 0)
return pos;
return NULL;
}
return __dsos__findnew_by_longname_id(&dsos->root, name, id);
}
struct dso *__dsos__find(struct dsos *dsos, const char *name, bool cmp_short)
{
return __dsos__find_id(dsos, name, NULL, cmp_short);
}
static void dso__set_basename(struct dso *dso)
{
char *base, *lname;
int tid;
if (sscanf(dso->long_name, "/tmp/perf-%d.map", &tid) == 1) {
if (asprintf(&base, "[JIT] tid %d", tid) < 0)
return;
} else {
/*
* basename() may modify path buffer, so we must pass
* a copy.
*/
lname = strdup(dso->long_name);
if (!lname)
return;
/*
* basename() may return a pointer to internal
* storage which is reused in subsequent calls
* so copy the result.
*/
base = strdup(basename(lname));
free(lname);
if (!base)
return;
}
dso__set_short_name(dso, base, true);
}
static struct dso *__dsos__addnew_id(struct dsos *dsos, const char *name, struct dso_id *id)
{
struct dso *dso = dso__new_id(name, id);
if (dso != NULL) {
__dsos__add(dsos, dso);
dso__set_basename(dso);
/* Put dso here because __dsos_add already got it */
dso__put(dso);
}
return dso;
}
struct dso *__dsos__addnew(struct dsos *dsos, const char *name)
{
return __dsos__addnew_id(dsos, name, NULL);
}
static struct dso *__dsos__findnew_id(struct dsos *dsos, const char *name, struct dso_id *id)
{
struct dso *dso = __dsos__find_id(dsos, name, id, false);
if (dso && dso_id__empty(&dso->id) && !dso_id__empty(id))
dso__inject_id(dso, id);
return dso ? dso : __dsos__addnew_id(dsos, name, id);
}
struct dso *dsos__findnew_id(struct dsos *dsos, const char *name, struct dso_id *id)
{
struct dso *dso;
down_write(&dsos->lock);
dso = dso__get(__dsos__findnew_id(dsos, name, id));
up_write(&dsos->lock);
return dso;
}
size_t __dsos__fprintf_buildid(struct list_head *head, FILE *fp,
bool (skip)(struct dso *dso, int parm), int parm)
{
struct dso *pos;
size_t ret = 0;
list_for_each_entry(pos, head, node) {
if (skip && skip(pos, parm))
continue;
ret += dso__fprintf_buildid(pos, fp);
ret += fprintf(fp, " %s\n", pos->long_name);
}
return ret;
}
size_t __dsos__fprintf(struct list_head *head, FILE *fp)
{
struct dso *pos;
size_t ret = 0;
list_for_each_entry(pos, head, node) {
ret += dso__fprintf(pos, fp);
}
return ret;
}