1 files changed, 29 insertions, 22 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 59ef2802fcf6..814e954c1318 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -606,12 +606,17 @@ static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
 	return evlist->mmap != NULL ? 0 : -ENOMEM;
 }
 
-static int __perf_evlist__mmap(struct perf_evlist *evlist,
-			       int idx, int prot, int mask, int fd)
+struct mmap_params {
+	int prot;
+	int mask;
+};
+
+static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
+			       struct mmap_params *mp, int fd)
 {
 	evlist->mmap[idx].prev = 0;
-	evlist->mmap[idx].mask = mask;
-	evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
+	evlist->mmap[idx].mask = mp->mask;
+	evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
 				      MAP_SHARED, fd, 0);
 	if (evlist->mmap[idx].base == MAP_FAILED) {
 		pr_debug2("failed to mmap perf event ring buffer, error %d\n",
@@ -625,8 +630,8 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist,
 }
 
 static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
-				       int prot, int mask, int cpu, int thread,
-				       int *output)
+				       struct mmap_params *mp, int cpu,
+				       int thread, int *output)
 {
 	struct perf_evsel *evsel;
 
@@ -635,8 +640,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
 
 		if (*output == -1) {
 			*output = fd;
-			if (__perf_evlist__mmap(evlist, idx, prot, mask,
-						*output) < 0)
+			if (__perf_evlist__mmap(evlist, idx, mp, *output) < 0)
 				return -1;
 		} else {
 			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
@@ -651,8 +655,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
 	return 0;
 }
 
-static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot,
-				     int mask)
+static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
+				     struct mmap_params *mp)
 {
 	int cpu, thread;
 	int nr_cpus = cpu_map__nr(evlist->cpus);
@@ -663,8 +667,8 @@ static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot,
 		int output = -1;
 
 		for (thread = 0; thread < nr_threads; thread++) {
-			if (perf_evlist__mmap_per_evsel(evlist, cpu, prot, mask,
-							cpu, thread, &output))
+			if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
+							thread, &output))
 				goto out_unmap;
 		}
 	}
@@ -677,8 +681,8 @@ out_unmap:
 	return -1;
 }
 
-static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot,
-					int mask)
+static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
+					struct mmap_params *mp)
 {
 	int thread;
 	int nr_threads = thread_map__nr(evlist->threads);
@@ -687,8 +691,8 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot,
 	for (thread = 0; thread < nr_threads; thread++) {
 		int output = -1;
 
-		if (perf_evlist__mmap_per_evsel(evlist, thread, prot, mask, 0,
-						thread, &output))
+		if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
+						&output))
 			goto out_unmap;
 	}
 
@@ -793,7 +797,9 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
 	struct perf_evsel *evsel;
 	const struct cpu_map *cpus = evlist->cpus;
 	const struct thread_map *threads = evlist->threads;
-	int prot = PROT_READ | (overwrite ? 0 : PROT_WRITE), mask;
+	struct mmap_params mp = {
+		.prot = PROT_READ | (overwrite ? 0 : PROT_WRITE),
+	};
 
 	if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
 		return -ENOMEM;
@@ -804,7 +810,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
 	evlist->overwrite = overwrite;
 	evlist->mmap_len = perf_evlist__mmap_size(pages);
 	pr_debug("mmap size %zuB\n", evlist->mmap_len);
-	mask = evlist->mmap_len - page_size - 1;
+	mp.mask = evlist->mmap_len - page_size - 1;
 
 	evlist__for_each(evlist, evsel) {
 		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
@@ -814,9 +820,9 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
 	}
 
 	if (cpu_map__empty(cpus))
-		return perf_evlist__mmap_per_thread(evlist, prot, mask);
+		return perf_evlist__mmap_per_thread(evlist, &mp);
 
-	return perf_evlist__mmap_per_cpu(evlist, prot, mask);
+	return perf_evlist__mmap_per_cpu(evlist, &mp);
 }
 
 int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
@@ -1214,10 +1220,11 @@ int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused,
 					     "For your workloads it needs to be <= 1\nHint:\t");
 		}
 		printed += scnprintf(buf + printed, size - printed,
-				     "For system wide tracing it needs to be set to -1");
+				     "For system wide tracing it needs to be set to -1.\n");
 
 		printed += scnprintf(buf + printed, size - printed,
-				    ".\nHint:\tThe current value is %d.", value);
+				    "Hint:\tTry: 'sudo sh -c \"echo -1 > /proc/sys/kernel/perf_event_paranoid\"'\n"
+				    "Hint:\tThe current value is %d.", value);
 		break;
 	default:
 		scnprintf(buf, size, "%s", emsg);