提交 dd975497 编写于 作者: M Masami Hiramatsu 提交者: Arnaldo Carvalho de Melo

perf probe: Introduce perf_cache interfaces

Introduce perf_cache object and interfaces to create, add entries,
commit, and delete the object.

perf_cache represents a file for the cached "perf probe" definitions on
one binary file or vmlinux which has its own build id. The probe cache
file is located under the build-id cache directory of the target binary,
as below;

  <perf-debug-dir>/.build-id/<BU>/<ILDID>/probe
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160615032830.31330.84998.stgit@devboxSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
上级 da1b0407
......@@ -14,6 +14,7 @@
* GNU General Public License for more details.
*
*/
#include <sys/uio.h>
#include "util.h"
#include "event.h"
#include "strlist.h"
......@@ -324,3 +325,333 @@ int probe_file__del_events(int fd, struct strfilter *filter)
return ret;
}
/* Caller must ensure to remove this entry from list */
static void probe_cache_entry__delete(struct probe_cache_entry *entry)
{
if (entry) {
BUG_ON(!list_empty(&entry->node));
strlist__delete(entry->tevlist);
clear_perf_probe_event(&entry->pev);
zfree(&entry->spev);
free(entry);
}
}
static struct probe_cache_entry *
probe_cache_entry__new(struct perf_probe_event *pev)
{
struct probe_cache_entry *entry = zalloc(sizeof(*entry));
if (entry) {
INIT_LIST_HEAD(&entry->node);
entry->tevlist = strlist__new(NULL, NULL);
if (!entry->tevlist)
zfree(&entry);
else if (pev) {
entry->spev = synthesize_perf_probe_command(pev);
if (!entry->spev ||
perf_probe_event__copy(&entry->pev, pev) < 0) {
probe_cache_entry__delete(entry);
return NULL;
}
}
}
return entry;
}
/* For the kernel probe caches, pass target = NULL */
static int probe_cache__open(struct probe_cache *pcache, const char *target)
{
char cpath[PATH_MAX];
char sbuildid[SBUILD_ID_SIZE];
char *dir_name;
bool is_kallsyms = !target;
int ret, fd;
if (target)
ret = filename__sprintf_build_id(target, sbuildid);
else {
target = DSO__NAME_KALLSYMS;
ret = sysfs__sprintf_build_id("/", sbuildid);
}
if (ret < 0) {
pr_debug("Failed to get build-id from %s.\n", target);
return ret;
}
/* If we have no buildid cache, make it */
if (!build_id_cache__cached(sbuildid)) {
ret = build_id_cache__add_s(sbuildid, target,
is_kallsyms, NULL);
if (ret < 0) {
pr_debug("Failed to add build-id cache: %s\n", target);
return ret;
}
}
dir_name = build_id_cache__cachedir(sbuildid, target, is_kallsyms,
false);
if (!dir_name)
return -ENOMEM;
snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
fd = open(cpath, O_CREAT | O_RDWR, 0644);
if (fd < 0)
pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
free(dir_name);
pcache->fd = fd;
return fd;
}
static int probe_cache__load(struct probe_cache *pcache)
{
struct probe_cache_entry *entry = NULL;
char buf[MAX_CMDLEN], *p;
int ret = 0;
FILE *fp;
fp = fdopen(dup(pcache->fd), "r");
if (!fp)
return -EINVAL;
while (!feof(fp)) {
if (!fgets(buf, MAX_CMDLEN, fp))
break;
p = strchr(buf, '\n');
if (p)
*p = '\0';
if (buf[0] == '#') { /* #perf_probe_event */
entry = probe_cache_entry__new(NULL);
if (!entry) {
ret = -ENOMEM;
goto out;
}
entry->spev = strdup(buf + 1);
if (entry->spev)
ret = parse_perf_probe_command(buf + 1,
&entry->pev);
else
ret = -ENOMEM;
if (ret < 0) {
probe_cache_entry__delete(entry);
goto out;
}
list_add_tail(&entry->node, &pcache->entries);
} else { /* trace_probe_event */
if (!entry) {
ret = -EINVAL;
goto out;
}
strlist__add(entry->tevlist, buf);
}
}
out:
fclose(fp);
return ret;
}
static struct probe_cache *probe_cache__alloc(void)
{
struct probe_cache *pcache = zalloc(sizeof(*pcache));
if (pcache) {
INIT_LIST_HEAD(&pcache->entries);
pcache->fd = -EINVAL;
}
return pcache;
}
void probe_cache__purge(struct probe_cache *pcache)
{
struct probe_cache_entry *entry, *n;
list_for_each_entry_safe(entry, n, &pcache->entries, node) {
list_del_init(&entry->node);
probe_cache_entry__delete(entry);
}
}
void probe_cache__delete(struct probe_cache *pcache)
{
if (!pcache)
return;
probe_cache__purge(pcache);
if (pcache->fd > 0)
close(pcache->fd);
free(pcache);
}
struct probe_cache *probe_cache__new(const char *target)
{
struct probe_cache *pcache = probe_cache__alloc();
int ret;
if (!pcache)
return NULL;
ret = probe_cache__open(pcache, target);
if (ret < 0) {
pr_debug("Cache open error: %d\n", ret);
goto out_err;
}
ret = probe_cache__load(pcache);
if (ret < 0) {
pr_debug("Cache read error: %d\n", ret);
goto out_err;
}
return pcache;
out_err:
probe_cache__delete(pcache);
return NULL;
}
static bool streql(const char *a, const char *b)
{
if (a == b)
return true;
if (!a || !b)
return false;
return !strcmp(a, b);
}
static struct probe_cache_entry *
probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
{
struct probe_cache_entry *entry = NULL;
char *cmd = synthesize_perf_probe_command(pev);
if (!cmd)
return NULL;
list_for_each_entry(entry, &pcache->entries, node) {
/* Hit if same event name or same command-string */
if ((pev->event &&
(streql(entry->pev.group, pev->group) &&
streql(entry->pev.event, pev->event))) ||
(!strcmp(entry->spev, cmd)))
goto found;
}
entry = NULL;
found:
free(cmd);
return entry;
}
int probe_cache__add_entry(struct probe_cache *pcache,
struct perf_probe_event *pev,
struct probe_trace_event *tevs, int ntevs)
{
struct probe_cache_entry *entry = NULL;
char *command;
int i, ret = 0;
if (!pcache || !pev || !tevs || ntevs <= 0) {
ret = -EINVAL;
goto out_err;
}
/* Remove old cache entry */
entry = probe_cache__find(pcache, pev);
if (entry) {
list_del_init(&entry->node);
probe_cache_entry__delete(entry);
}
ret = -ENOMEM;
entry = probe_cache_entry__new(pev);
if (!entry)
goto out_err;
for (i = 0; i < ntevs; i++) {
if (!tevs[i].point.symbol)
continue;
command = synthesize_probe_trace_command(&tevs[i]);
if (!command)
goto out_err;
strlist__add(entry->tevlist, command);
free(command);
}
list_add_tail(&entry->node, &pcache->entries);
pr_debug("Added probe cache: %d\n", ntevs);
return 0;
out_err:
pr_debug("Failed to add probe caches\n");
probe_cache_entry__delete(entry);
return ret;
}
static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
{
struct str_node *snode;
struct stat st;
struct iovec iov[3];
int ret;
/* Save stat for rollback */
ret = fstat(fd, &st);
if (ret < 0)
return ret;
pr_debug("Writing cache: #%s\n", entry->spev);
iov[0].iov_base = (void *)"#"; iov[0].iov_len = 1;
iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
ret = writev(fd, iov, 3);
if (ret < (int)iov[1].iov_len + 2)
goto rollback;
strlist__for_each(snode, entry->tevlist) {
iov[0].iov_base = (void *)snode->s;
iov[0].iov_len = strlen(snode->s);
iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
ret = writev(fd, iov, 2);
if (ret < (int)iov[0].iov_len + 1)
goto rollback;
}
return 0;
rollback:
/* Rollback to avoid cache file corruption */
if (ret > 0)
ret = -1;
if (ftruncate(fd, st.st_size) < 0)
ret = -2;
return ret;
}
int probe_cache__commit(struct probe_cache *pcache)
{
struct probe_cache_entry *entry;
int ret = 0;
/* TBD: if we do not update existing entries, skip it */
ret = lseek(pcache->fd, 0, SEEK_SET);
if (ret < 0)
goto out;
ret = ftruncate(pcache->fd, 0);
if (ret < 0)
goto out;
list_for_each_entry(entry, &pcache->entries, node) {
ret = probe_cache_entry__write(entry, pcache->fd);
pr_debug("Cache committed: %d\n", ret);
if (ret < 0)
break;
}
out:
return ret;
}
......@@ -5,6 +5,19 @@
#include "strfilter.h"
#include "probe-event.h"
/* Cache of probe definitions */
struct probe_cache_entry {
struct list_head node;
struct perf_probe_event pev;
char *spev;
struct strlist *tevlist;
};
struct probe_cache {
int fd;
struct list_head entries;
};
#define PF_FL_UPROBE 1
#define PF_FL_RW 2
......@@ -18,5 +31,12 @@ int probe_file__get_events(int fd, struct strfilter *filter,
struct strlist *plist);
int probe_file__del_strlist(int fd, struct strlist *namelist);
struct probe_cache *probe_cache__new(const char *target);
int probe_cache__add_entry(struct probe_cache *pcache,
struct perf_probe_event *pev,
struct probe_trace_event *tevs, int ntevs);
int probe_cache__commit(struct probe_cache *pcache);
void probe_cache__purge(struct probe_cache *pcache);
void probe_cache__delete(struct probe_cache *pcache);
#endif
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