mirror of https://gitee.com/openkylin/linux.git
perf tools: Add time out to force stop proc map processing
System wide sampling like 'perf top' or 'perf record -a' read all threads /proc/xxx/maps before sampling. If there are any threads which generating a keeping growing huge maps, perf will do infinite loop during synthesizing. Nothing will be sampled. This patch fixes this issue by adding per-thread timeout to force stop this kind of endless proc map processing. PERF_RECORD_MISC_PROC_MAP_PARSE_TIME_OUT is introduced to indicate that the mmap record are truncated by time out. User will get warning notification when truncated mmap records are detected. Reported-by: Ying Huang <ying.huang@intel.com> Signed-off-by: Kan Liang <kan.liang@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Ahern <dsahern@gmail.com> Cc: Ying Huang <ying.huang@intel.com> Link: http://lkml.kernel.org/r/1434549071-25611-1-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -565,6 +565,10 @@ struct perf_event_mmap_page {
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#define PERF_RECORD_MISC_GUEST_KERNEL (4 << 0)
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#define PERF_RECORD_MISC_GUEST_USER (5 << 0)
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/*
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* Indicates that /proc/PID/maps parsing are truncated by time out.
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*/
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#define PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT (1 << 12)
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/*
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* PERF_RECORD_MISC_MMAP_DATA and PERF_RECORD_MISC_COMM_EXEC are used on
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* different events so can reuse the same bit position.
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@ -213,6 +213,8 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
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return 0;
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}
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#define PROC_MAP_PARSE_TIMEOUT (500 * 1000000ULL)
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int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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union perf_event *event,
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pid_t pid, pid_t tgid,
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@ -222,6 +224,8 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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{
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char filename[PATH_MAX];
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FILE *fp;
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unsigned long long t;
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bool truncation = false;
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int rc = 0;
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if (machine__is_default_guest(machine))
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@ -240,6 +244,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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}
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event->header.type = PERF_RECORD_MMAP2;
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t = rdclock();
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while (1) {
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char bf[BUFSIZ];
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@ -253,6 +258,12 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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if (fgets(bf, sizeof(bf), fp) == NULL)
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break;
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if ((rdclock() - t) > PROC_MAP_PARSE_TIMEOUT) {
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pr_warning("Reading %s time out.\n", filename);
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truncation = true;
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goto out;
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}
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/* ensure null termination since stack will be reused. */
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strcpy(execname, "");
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@ -301,6 +312,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
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}
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out:
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if (truncation)
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event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT;
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if (!strcmp(execname, ""))
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strcpy(execname, anonstr);
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@ -319,6 +334,9 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
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rc = -1;
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break;
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}
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if (truncation)
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break;
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}
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fclose(fp);
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@ -265,6 +265,7 @@ struct events_stats {
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u32 nr_unknown_id;
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u32 nr_unprocessable_samples;
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u32 nr_auxtrace_errors[PERF_AUXTRACE_ERROR_MAX];
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u32 nr_proc_map_timeout;
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};
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struct attr_event {
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@ -1064,6 +1064,8 @@ static int machines__deliver_event(struct machines *machines,
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case PERF_RECORD_MMAP:
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return tool->mmap(tool, event, sample, machine);
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case PERF_RECORD_MMAP2:
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if (event->header.misc & PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT)
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++evlist->stats.nr_proc_map_timeout;
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return tool->mmap2(tool, event, sample, machine);
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case PERF_RECORD_COMM:
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return tool->comm(tool, event, sample, machine);
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@ -1360,6 +1362,15 @@ static void perf_session__warn_about_errors(const struct perf_session *session)
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ui__warning("%u out of order events recorded.\n", oe->nr_unordered_events);
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events_stats__auxtrace_error_warn(stats);
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if (stats->nr_proc_map_timeout != 0) {
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ui__warning("%d map information files for pre-existing threads were\n"
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"not processed, if there are samples for addresses they\n"
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"will not be resolved, you may find out which are these\n"
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"threads by running with -v and redirecting the output\n"
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"to a file.\n",
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stats->nr_proc_map_timeout);
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}
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}
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static int perf_session__flush_thread_stack(struct thread *thread,
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