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: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Masami 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@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu
Arnaldo Carvalho de Melo
parent
da1b0407c8
commit
dd975497ad
@ -14,6 +14,7 @@
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* GNU General Public License for more details.
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*
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*/
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#include <sys/uio.h>
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#include "util.h"
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#include "event.h"
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#include "strlist.h"
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@ -324,3 +325,333 @@ int probe_file__del_events(int fd, struct strfilter *filter)
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return ret;
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}
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/* Caller must ensure to remove this entry from list */
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static void probe_cache_entry__delete(struct probe_cache_entry *entry)
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{
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if (entry) {
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BUG_ON(!list_empty(&entry->node));
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strlist__delete(entry->tevlist);
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clear_perf_probe_event(&entry->pev);
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zfree(&entry->spev);
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free(entry);
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}
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}
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static struct probe_cache_entry *
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probe_cache_entry__new(struct perf_probe_event *pev)
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{
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struct probe_cache_entry *entry = zalloc(sizeof(*entry));
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if (entry) {
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INIT_LIST_HEAD(&entry->node);
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entry->tevlist = strlist__new(NULL, NULL);
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if (!entry->tevlist)
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zfree(&entry);
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else if (pev) {
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entry->spev = synthesize_perf_probe_command(pev);
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if (!entry->spev ||
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perf_probe_event__copy(&entry->pev, pev) < 0) {
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probe_cache_entry__delete(entry);
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return NULL;
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}
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}
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}
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return entry;
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}
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/* For the kernel probe caches, pass target = NULL */
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static int probe_cache__open(struct probe_cache *pcache, const char *target)
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{
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char cpath[PATH_MAX];
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char sbuildid[SBUILD_ID_SIZE];
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char *dir_name;
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bool is_kallsyms = !target;
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int ret, fd;
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if (target)
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ret = filename__sprintf_build_id(target, sbuildid);
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else {
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target = DSO__NAME_KALLSYMS;
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ret = sysfs__sprintf_build_id("/", sbuildid);
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}
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if (ret < 0) {
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pr_debug("Failed to get build-id from %s.\n", target);
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return ret;
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}
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/* If we have no buildid cache, make it */
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if (!build_id_cache__cached(sbuildid)) {
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ret = build_id_cache__add_s(sbuildid, target,
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is_kallsyms, NULL);
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if (ret < 0) {
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pr_debug("Failed to add build-id cache: %s\n", target);
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return ret;
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}
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}
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dir_name = build_id_cache__cachedir(sbuildid, target, is_kallsyms,
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false);
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if (!dir_name)
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return -ENOMEM;
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snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
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fd = open(cpath, O_CREAT | O_RDWR, 0644);
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if (fd < 0)
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pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
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free(dir_name);
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pcache->fd = fd;
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return fd;
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}
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static int probe_cache__load(struct probe_cache *pcache)
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{
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struct probe_cache_entry *entry = NULL;
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char buf[MAX_CMDLEN], *p;
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int ret = 0;
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FILE *fp;
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fp = fdopen(dup(pcache->fd), "r");
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if (!fp)
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return -EINVAL;
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while (!feof(fp)) {
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if (!fgets(buf, MAX_CMDLEN, fp))
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break;
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p = strchr(buf, '\n');
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if (p)
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*p = '\0';
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if (buf[0] == '#') { /* #perf_probe_event */
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entry = probe_cache_entry__new(NULL);
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if (!entry) {
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ret = -ENOMEM;
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goto out;
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}
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entry->spev = strdup(buf + 1);
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if (entry->spev)
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ret = parse_perf_probe_command(buf + 1,
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&entry->pev);
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else
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ret = -ENOMEM;
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if (ret < 0) {
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probe_cache_entry__delete(entry);
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goto out;
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}
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list_add_tail(&entry->node, &pcache->entries);
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} else { /* trace_probe_event */
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if (!entry) {
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ret = -EINVAL;
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goto out;
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}
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strlist__add(entry->tevlist, buf);
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}
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}
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out:
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fclose(fp);
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return ret;
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}
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static struct probe_cache *probe_cache__alloc(void)
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{
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struct probe_cache *pcache = zalloc(sizeof(*pcache));
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if (pcache) {
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INIT_LIST_HEAD(&pcache->entries);
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pcache->fd = -EINVAL;
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}
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return pcache;
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}
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void probe_cache__purge(struct probe_cache *pcache)
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{
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struct probe_cache_entry *entry, *n;
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list_for_each_entry_safe(entry, n, &pcache->entries, node) {
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list_del_init(&entry->node);
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probe_cache_entry__delete(entry);
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}
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}
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void probe_cache__delete(struct probe_cache *pcache)
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{
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if (!pcache)
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return;
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probe_cache__purge(pcache);
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if (pcache->fd > 0)
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close(pcache->fd);
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free(pcache);
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}
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struct probe_cache *probe_cache__new(const char *target)
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{
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struct probe_cache *pcache = probe_cache__alloc();
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int ret;
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if (!pcache)
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return NULL;
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ret = probe_cache__open(pcache, target);
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if (ret < 0) {
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pr_debug("Cache open error: %d\n", ret);
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goto out_err;
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}
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ret = probe_cache__load(pcache);
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if (ret < 0) {
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pr_debug("Cache read error: %d\n", ret);
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goto out_err;
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}
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return pcache;
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out_err:
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probe_cache__delete(pcache);
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return NULL;
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}
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static bool streql(const char *a, const char *b)
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{
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if (a == b)
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return true;
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if (!a || !b)
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return false;
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return !strcmp(a, b);
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}
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static struct probe_cache_entry *
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probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
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{
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struct probe_cache_entry *entry = NULL;
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char *cmd = synthesize_perf_probe_command(pev);
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if (!cmd)
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return NULL;
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list_for_each_entry(entry, &pcache->entries, node) {
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/* Hit if same event name or same command-string */
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if ((pev->event &&
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(streql(entry->pev.group, pev->group) &&
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streql(entry->pev.event, pev->event))) ||
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(!strcmp(entry->spev, cmd)))
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goto found;
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}
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entry = NULL;
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found:
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free(cmd);
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return entry;
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}
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int probe_cache__add_entry(struct probe_cache *pcache,
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struct perf_probe_event *pev,
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struct probe_trace_event *tevs, int ntevs)
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{
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struct probe_cache_entry *entry = NULL;
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char *command;
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int i, ret = 0;
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if (!pcache || !pev || !tevs || ntevs <= 0) {
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ret = -EINVAL;
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goto out_err;
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}
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/* Remove old cache entry */
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entry = probe_cache__find(pcache, pev);
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if (entry) {
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list_del_init(&entry->node);
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probe_cache_entry__delete(entry);
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}
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ret = -ENOMEM;
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entry = probe_cache_entry__new(pev);
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if (!entry)
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goto out_err;
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for (i = 0; i < ntevs; i++) {
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if (!tevs[i].point.symbol)
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continue;
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command = synthesize_probe_trace_command(&tevs[i]);
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if (!command)
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goto out_err;
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strlist__add(entry->tevlist, command);
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free(command);
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}
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list_add_tail(&entry->node, &pcache->entries);
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pr_debug("Added probe cache: %d\n", ntevs);
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return 0;
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out_err:
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pr_debug("Failed to add probe caches\n");
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probe_cache_entry__delete(entry);
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return ret;
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}
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static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
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{
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struct str_node *snode;
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struct stat st;
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struct iovec iov[3];
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int ret;
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/* Save stat for rollback */
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ret = fstat(fd, &st);
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if (ret < 0)
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return ret;
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pr_debug("Writing cache: #%s\n", entry->spev);
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iov[0].iov_base = (void *)"#"; iov[0].iov_len = 1;
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iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
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iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
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ret = writev(fd, iov, 3);
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if (ret < (int)iov[1].iov_len + 2)
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goto rollback;
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strlist__for_each(snode, entry->tevlist) {
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iov[0].iov_base = (void *)snode->s;
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iov[0].iov_len = strlen(snode->s);
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iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
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ret = writev(fd, iov, 2);
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if (ret < (int)iov[0].iov_len + 1)
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goto rollback;
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}
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return 0;
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rollback:
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/* Rollback to avoid cache file corruption */
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if (ret > 0)
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ret = -1;
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if (ftruncate(fd, st.st_size) < 0)
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ret = -2;
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return ret;
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}
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int probe_cache__commit(struct probe_cache *pcache)
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{
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struct probe_cache_entry *entry;
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int ret = 0;
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/* TBD: if we do not update existing entries, skip it */
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ret = lseek(pcache->fd, 0, SEEK_SET);
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if (ret < 0)
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goto out;
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ret = ftruncate(pcache->fd, 0);
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if (ret < 0)
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goto out;
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list_for_each_entry(entry, &pcache->entries, node) {
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ret = probe_cache_entry__write(entry, pcache->fd);
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pr_debug("Cache committed: %d\n", ret);
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if (ret < 0)
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break;
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}
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out:
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return ret;
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}
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@ -5,6 +5,19 @@
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#include "strfilter.h"
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#include "probe-event.h"
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/* Cache of probe definitions */
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struct probe_cache_entry {
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struct list_head node;
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struct perf_probe_event pev;
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char *spev;
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struct strlist *tevlist;
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};
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struct probe_cache {
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int fd;
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struct list_head entries;
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};
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#define PF_FL_UPROBE 1
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#define PF_FL_RW 2
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@ -18,5 +31,12 @@ int probe_file__get_events(int fd, struct strfilter *filter,
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struct strlist *plist);
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int probe_file__del_strlist(int fd, struct strlist *namelist);
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struct probe_cache *probe_cache__new(const char *target);
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int probe_cache__add_entry(struct probe_cache *pcache,
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struct perf_probe_event *pev,
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struct probe_trace_event *tevs, int ntevs);
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int probe_cache__commit(struct probe_cache *pcache);
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void probe_cache__purge(struct probe_cache *pcache);
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void probe_cache__delete(struct probe_cache *pcache);
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#endif
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