scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 263 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
new file mode 100644
index 000000000..23f488cf1
--- /dev/null
+++ b/tools/bpf/bpftool/pids.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2020 Facebook */
+#include <errno.h>
+#include <linux/err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <bpf/bpf.h>
+#include <bpf/hashmap.h>
+
+#include "main.h"
+#include "skeleton/pid_iter.h"
+
+#ifdef BPFTOOL_WITHOUT_SKELETONS
+
+int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type)
+{
+	return -ENOTSUP;
+}
+void delete_obj_refs_table(struct hashmap *map) {}
+void emit_obj_refs_plain(struct hashmap *map, __u32 id, const char *prefix) {}
+void emit_obj_refs_json(struct hashmap *map, __u32 id, json_writer_t *json_writer) {}
+
+#else /* BPFTOOL_WITHOUT_SKELETONS */
+
+#include "pid_iter.skel.h"
+
+static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
+{
+	struct hashmap_entry *entry;
+	struct obj_refs *refs;
+	struct obj_ref *ref;
+	int err, i;
+	void *tmp;
+
+	hashmap__for_each_key_entry(map, entry, e->id) {
+		refs = entry->pvalue;
+
+		for (i = 0; i < refs->ref_cnt; i++) {
+			if (refs->refs[i].pid == e->pid)
+				return;
+		}
+
+		tmp = realloc(refs->refs, (refs->ref_cnt + 1) * sizeof(*ref));
+		if (!tmp) {
+			p_err("failed to re-alloc memory for ID %u, PID %d, COMM %s...",
+			      e->id, e->pid, e->comm);
+			return;
+		}
+		refs->refs = tmp;
+		ref = &refs->refs[refs->ref_cnt];
+		ref->pid = e->pid;
+		memcpy(ref->comm, e->comm, sizeof(ref->comm));
+		ref->comm[sizeof(ref->comm) - 1] = '\0';
+		refs->ref_cnt++;
+
+		return;
+	}
+
+	/* new ref */
+	refs = calloc(1, sizeof(*refs));
+	if (!refs) {
+		p_err("failed to alloc memory for ID %u, PID %d, COMM %s...",
+		      e->id, e->pid, e->comm);
+		return;
+	}
+
+	refs->refs = malloc(sizeof(*refs->refs));
+	if (!refs->refs) {
+		free(refs);
+		p_err("failed to alloc memory for ID %u, PID %d, COMM %s...",
+		      e->id, e->pid, e->comm);
+		return;
+	}
+	ref = &refs->refs[0];
+	ref->pid = e->pid;
+	memcpy(ref->comm, e->comm, sizeof(ref->comm));
+	ref->comm[sizeof(ref->comm) - 1] = '\0';
+	refs->ref_cnt = 1;
+	refs->has_bpf_cookie = e->has_bpf_cookie;
+	refs->bpf_cookie = e->bpf_cookie;
+
+	err = hashmap__append(map, e->id, refs);
+	if (err)
+		p_err("failed to append entry to hashmap for ID %u: %s",
+		      e->id, strerror(errno));
+}
+
+static int __printf(2, 0)
+libbpf_print_none(__maybe_unused enum libbpf_print_level level,
+		  __maybe_unused const char *format,
+		  __maybe_unused va_list args)
+{
+	return 0;
+}
+
+int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type)
+{
+	struct pid_iter_entry *e;
+	char buf[4096 / sizeof(*e) * sizeof(*e)];
+	struct pid_iter_bpf *skel;
+	int err, ret, fd = -1, i;
+
+	*map = hashmap__new(hash_fn_for_key_as_id, equal_fn_for_key_as_id, NULL);
+	if (IS_ERR(*map)) {
+		p_err("failed to create hashmap for PID references");
+		return -1;
+	}
+	set_max_rlimit();
+
+	skel = pid_iter_bpf__open();
+	if (!skel) {
+		p_err("failed to open PID iterator skeleton");
+		return -1;
+	}
+
+	skel->rodata->obj_type = type;
+
+	if (!verifier_logs) {
+		libbpf_print_fn_t default_print;
+
+		/* Unless debug information is on, we don't want the output to
+		 * be polluted with libbpf errors if bpf_iter is not supported.
+		 */
+		default_print = libbpf_set_print(libbpf_print_none);
+		err = pid_iter_bpf__load(skel);
+		libbpf_set_print(default_print);
+	} else {
+		err = pid_iter_bpf__load(skel);
+	}
+	if (err) {
+		/* too bad, kernel doesn't support BPF iterators yet */
+		err = 0;
+		goto out;
+	}
+	err = pid_iter_bpf__attach(skel);
+	if (err) {
+		/* if we loaded above successfully, attach has to succeed */
+		p_err("failed to attach PID iterator: %d", err);
+		goto out;
+	}
+
+	fd = bpf_iter_create(bpf_link__fd(skel->links.iter));
+	if (fd < 0) {
+		err = -errno;
+		p_err("failed to create PID iterator session: %d", err);
+		goto out;
+	}
+
+	while (true) {
+		ret = read(fd, buf, sizeof(buf));
+		if (ret < 0) {
+			if (errno == EAGAIN)
+				continue;
+			err = -errno;
+			p_err("failed to read PID iterator output: %d", err);
+			goto out;
+		}
+		if (ret == 0)
+			break;
+		if (ret % sizeof(*e)) {
+			err = -EINVAL;
+			p_err("invalid PID iterator output format");
+			goto out;
+		}
+		ret /= sizeof(*e);
+
+		e = (void *)buf;
+		for (i = 0; i < ret; i++, e++) {
+			add_ref(*map, e);
+		}
+	}
+	err = 0;
+out:
+	if (fd >= 0)
+		close(fd);
+	pid_iter_bpf__destroy(skel);
+	return err;
+}
+
+void delete_obj_refs_table(struct hashmap *map)
+{
+	struct hashmap_entry *entry;
+	size_t bkt;
+
+	if (!map)
+		return;
+
+	hashmap__for_each_entry(map, entry, bkt) {
+		struct obj_refs *refs = entry->pvalue;
+
+		free(refs->refs);
+		free(refs);
+	}
+
+	hashmap__free(map);
+}
+
+void emit_obj_refs_json(struct hashmap *map, __u32 id,
+			json_writer_t *json_writer)
+{
+	struct hashmap_entry *entry;
+
+	if (hashmap__empty(map))
+		return;
+
+	hashmap__for_each_key_entry(map, entry, id) {
+		struct obj_refs *refs = entry->pvalue;
+		int i;
+
+		if (refs->ref_cnt == 0)
+			break;
+
+		if (refs->has_bpf_cookie)
+			jsonw_lluint_field(json_writer, "bpf_cookie", refs->bpf_cookie);
+
+		jsonw_name(json_writer, "pids");
+		jsonw_start_array(json_writer);
+		for (i = 0; i < refs->ref_cnt; i++) {
+			struct obj_ref *ref = &refs->refs[i];
+
+			jsonw_start_object(json_writer);
+			jsonw_int_field(json_writer, "pid", ref->pid);
+			jsonw_string_field(json_writer, "comm", ref->comm);
+			jsonw_end_object(json_writer);
+		}
+		jsonw_end_array(json_writer);
+		break;
+	}
+}
+
+void emit_obj_refs_plain(struct hashmap *map, __u32 id, const char *prefix)
+{
+	struct hashmap_entry *entry;
+
+	if (hashmap__empty(map))
+		return;
+
+	hashmap__for_each_key_entry(map, entry, id) {
+		struct obj_refs *refs = entry->pvalue;
+		int i;
+
+		if (refs->ref_cnt == 0)
+			break;
+
+		if (refs->has_bpf_cookie)
+			printf("\n\tbpf_cookie %llu", (unsigned long long) refs->bpf_cookie);
+
+		printf("%s", prefix);
+		for (i = 0; i < refs->ref_cnt; i++) {
+			struct obj_ref *ref = &refs->refs[i];
+
+			printf("%s%s(%d)", i == 0 ? "" : ", ", ref->comm, ref->pid);
+		}
+		break;
+	}
+}
+
+
+#endif