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perf cgroup: Make the cgroup name be const char *

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The usual thing is for a constructor to allocate space for its members,
not to require that the caller pass a pre-allocated 'name' and then, at
its destructor, to free something not allocated by it.

Fix it by making cgroup__new() to receive a const char pointer, then
allocate cgroup->name that then can continue to be freed at
cgroup__delete(), balancing the alloc/free operations inside the cgroup
struct methods.

This eases calling evlist__findnew_cgroup() from the custom 'perf trace'
cgroup parser, that will only call parse_cgroups() when the '-G cgroup'
is passed on the command line after '-e event' entries, when it'll
behave just like 'perf stat' and 'perf record', i.e. the previous
parse_cgroup() users that mandate that -G only can come after a -e.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-4leugnuyqi10t98990o3xi1t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
2018-03-06 15:53:22 -03:00
parent 483322dda0
commit 3b5692864d
2 changed files with 15 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
tools/perf/util/cgroup.c
View File

@@ -71,7 +71,7 @@ cgroupfs_find_mountpoint(char *buf, size_t maxlen)
return -1; return -1;
} }
static int open_cgroup(char *name) static int open_cgroup(const char *name)
{ {
char path[PATH_MAX + 1]; char path[PATH_MAX + 1];
char mnt[PATH_MAX + 1]; char mnt[PATH_MAX + 1];
@@ -90,7 +90,7 @@ static int open_cgroup(char *name)
return fd; return fd;
} }
static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, char *str) static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
{ {
struct perf_evsel *counter; struct perf_evsel *counter;
struct cgroup *cgrp = NULL; struct cgroup *cgrp = NULL;
@@ -109,33 +109,38 @@ static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, char *str)
return cgrp; return cgrp;
} }
static struct cgroup *cgroup__new(char *name) static struct cgroup *cgroup__new(const char *name)
{ {
struct cgroup *cgroup = zalloc(sizeof(*cgroup)); struct cgroup *cgroup = zalloc(sizeof(*cgroup));
if (cgroup != NULL) { if (cgroup != NULL) {
cgroup->name = name;
refcount_set(&cgroup->refcnt, 1); refcount_set(&cgroup->refcnt, 1);
cgroup->name = strdup(name);
if (!cgroup->name)
goto out_err;
cgroup->fd = open_cgroup(name); cgroup->fd = open_cgroup(name);
if (cgroup->fd == -1) if (cgroup->fd == -1)
goto out_err; goto out_free_name;
} }
return cgroup; return cgroup;
out_free_name:
free(cgroup->name);
out_err: out_err:
free(cgroup); free(cgroup);
return NULL; return NULL;
} }
struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, char *name) struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
{ {
struct cgroup *cgroup = evlist__find_cgroup(evlist, name); struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
return cgroup ?: cgroup__new(name); return cgroup ?: cgroup__new(name);
} }
static int add_cgroup(struct perf_evlist *evlist, char *str) static int add_cgroup(struct perf_evlist *evlist, const char *str)
{ {
struct perf_evsel *counter; struct perf_evsel *counter;
struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str); struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
@@ -222,10 +227,9 @@ int parse_cgroups(const struct option *opt, const char *str,
if (!s) if (!s)
return -1; return -1;
ret = add_cgroup(evlist, s); ret = add_cgroup(evlist, s);
if (ret) { free(s);
free(s); if (ret)
return -1; return -1;
}
} }
/* nr_cgroups is increased een for empty cgroups */ /* nr_cgroups is increased een for empty cgroups */
nr_cgroups++; nr_cgroups++;

2
tools/perf/util/cgroup.h
View File

@@ -20,7 +20,7 @@ void cgroup__put(struct cgroup *cgroup);
struct perf_evlist; struct perf_evlist;
struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, char *name); struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name);
void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup); void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup);