Merge tag 'perf-core-for-mingo-5.8-20200420' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core fixes and improvements from Arnaldo Carvalho de Melo:

kernel + tools/perf:

  Alexey Budankov:

  - Introduce CAP_PERFMON to kernel and user space.

callchains:

  Adrian Hunter:

  - Allow using Intel PT to synthesize callchains for regular events.

  Kan Liang:

  - Stitch LBR records from multiple samples to get deeper backtraces,
    there are caveats, see the csets for details.

perf script:

  Andreas Gerstmayr:

  - Add flamegraph.py script

BPF:

  Jiri Olsa:

  - Synthesize bpf_trampoline/dispatcher ksymbol events.

perf stat:

  Arnaldo Carvalho de Melo:

  - Honour --timeout for forked workloads.

  Stephane Eranian:

  - Force error in fallback on :k events, to avoid counting nothing when
    the user asks for kernel events but is not allowed to.

perf bench:

  Ian Rogers:

  - Add event synthesis benchmark.

tools api fs:

  Stephane Eranian:

 - Make xxx__mountpoint() more scalable

libtraceevent:

  He Zhe:

  - Handle return value of asprintf.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 48 insertions, 10 deletions

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 027b18f7ed8c..82f53d81a7a7 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -90,6 +90,7 @@ struct fs {
 	const char * const	*mounts;
 	char			 path[PATH_MAX];
 	bool			 found;
+	bool			 checked;
 	long			 magic;
 };
 
@@ -111,31 +112,37 @@ static struct fs fs__entries[] = {
 		.name	= "sysfs",
 		.mounts	= sysfs__fs_known_mountpoints,
 		.magic	= SYSFS_MAGIC,
+		.checked = false,
 	},
 	[FS__PROCFS] = {
 		.name	= "proc",
 		.mounts	= procfs__known_mountpoints,
 		.magic	= PROC_SUPER_MAGIC,
+		.checked = false,
 	},
 	[FS__DEBUGFS] = {
 		.name	= "debugfs",
 		.mounts	= debugfs__known_mountpoints,
 		.magic	= DEBUGFS_MAGIC,
+		.checked = false,
 	},
 	[FS__TRACEFS] = {
 		.name	= "tracefs",
 		.mounts	= tracefs__known_mountpoints,
 		.magic	= TRACEFS_MAGIC,
+		.checked = false,
 	},
 	[FS__HUGETLBFS] = {
 		.name	= "hugetlbfs",
 		.mounts = hugetlbfs__known_mountpoints,
 		.magic	= HUGETLBFS_MAGIC,
+		.checked = false,
 	},
 	[FS__BPF_FS] = {
 		.name	= "bpf",
 		.mounts = bpf_fs__known_mountpoints,
 		.magic	= BPF_FS_MAGIC,
+		.checked = false,
 	},
 };
 
@@ -158,6 +165,7 @@ static bool fs__read_mounts(struct fs *fs)
 	}
 
 	fclose(fp);
+	fs->checked = true;
 	return fs->found = found;
 }
 
@@ -220,6 +228,7 @@ static bool fs__env_override(struct fs *fs)
 		return false;
 
 	fs->found = true;
+	fs->checked = true;
 	strncpy(fs->path, override_path, sizeof(fs->path) - 1);
 	fs->path[sizeof(fs->path) - 1] = '\0';
 	return true;
@@ -246,6 +255,14 @@ static const char *fs__mountpoint(int idx)
 	if (fs->found)
 		return (const char *)fs->path;
 
+	/* the mount point was already checked for the mount point
+	 * but and did not exist, so return NULL to avoid scanning again.
+	 * This makes the found and not found paths cost equivalent
+	 * in case of multiple calls.
+	 */
+	if (fs->checked)
+		return NULL;
+
 	return fs__get_mountpoint(fs);
 }
 
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
index 936edb95e1f3..aa222ca30311 100644
--- a/tools/lib/api/fs/fs.h
+++ b/tools/lib/api/fs/fs.h
@@ -18,6 +18,18 @@
 	const char *name##__mount(void);	\
 	bool name##__configured(void);		\
 
+/*
+ * The xxxx__mountpoint() entry points find the first match mount point for each
+ * filesystems listed below, where xxxx is the filesystem type.
+ *
+ * The interface is as follows:
+ *
+ * - If a mount point is found on first call, it is cached and used for all
+ *   subsequent calls.
+ *
+ * - If a mount point is not found, NULL is returned on first call and all
+ *   subsequent calls.
+ */
 FS(sysfs)
 FS(procfs)
 FS(debugfs)
diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 20eed719542e..c271aeeb227d 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1958,7 +1958,8 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
 				default:
 					break;
 				}
-				asprintf(&str, val ? "TRUE" : "FALSE");
+				if (asprintf(&str, val ? "TRUE" : "FALSE") < 0)
+					str = NULL;
 				break;
 			}
 		}
@@ -1976,7 +1977,8 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
 			break;
 		}
 
-		asprintf(&str, "(%s) %s (%s)", left, op, right);
+		if (asprintf(&str, "(%s) %s (%s)", left, op, right) < 0)
+			str = NULL;
 		break;
 
 	case TEP_FILTER_OP_NOT:
@@ -1992,10 +1994,12 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
 			right_val = 0;
 		if (right_val >= 0) {
 			/* just return the opposite */
-			asprintf(&str, right_val ? "FALSE" : "TRUE");
+			if (asprintf(&str, right_val ? "FALSE" : "TRUE") < 0)
+				str = NULL;
 			break;
 		}
-		asprintf(&str, "%s(%s)", op, right);
+		if (asprintf(&str, "%s(%s)", op, right) < 0)
+			str = NULL;
 		break;
 
 	default:
@@ -2011,7 +2015,8 @@ static char *val_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
 {
 	char *str = NULL;
 
-	asprintf(&str, "%lld", arg->value.val);
+	if (asprintf(&str, "%lld", arg->value.val) < 0)
+		str = NULL;
 
 	return str;
 }
@@ -2069,7 +2074,8 @@ static char *exp_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
 		break;
 	}
 
-	asprintf(&str, "%s %s %s", lstr, op, rstr);
+	if (asprintf(&str, "%s %s %s", lstr, op, rstr) < 0)
+		str = NULL;
 out:
 	free(lstr);
 	free(rstr);
@@ -2113,7 +2119,8 @@ static char *num_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
 		if (!op)
 			op = "<=";
 
-		asprintf(&str, "%s %s %s", lstr, op, rstr);
+		if (asprintf(&str, "%s %s %s", lstr, op, rstr) < 0)
+			str = NULL;
 		break;
 
 	default:
@@ -2148,8 +2155,9 @@ static char *str_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
 		if (!op)
 			op = "!~";
 
-		asprintf(&str, "%s %s \"%s\"",
-			 arg->str.field->name, op, arg->str.val);
+		if (asprintf(&str, "%s %s \"%s\"",
+			 arg->str.field->name, op, arg->str.val) < 0)
+			str = NULL;
 		break;
 
 	default:
@@ -2165,7 +2173,8 @@ static char *arg_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
 
 	switch (arg->type) {
 	case TEP_FILTER_ARG_BOOLEAN:
-		asprintf(&str, arg->boolean.value ? "TRUE" : "FALSE");
+		if (asprintf(&str, arg->boolean.value ? "TRUE" : "FALSE") < 0)
+			str = NULL;
 		return str;
 
 	case TEP_FILTER_ARG_OP: