From 71fe9db332172db3aad49a7a18c848f9ac8e14fb Mon Sep 17 00:00:00 2001
From: Serhei Makarov <serhei@serhei.io>
Date: Thu, 3 Nov 2022 12:56:11 -0400
Subject: [PATCH] Revert "runtime: stat: avoid allocating stat_data memory on
 offline CPUs"

This reverts commit ba42203ae957bb62805e18eac30459eb74cde3d2.
There are indications that on some non-x86 platforms (ppc64le)
this patch may be causing problems i.e.
'sleeping function called in invalid context' warnings.

Reverting for the release, may return this patch if I get a
clearer idea of the cause of the problem.
---
 runtime/linux/stat_runtime.h | 30 +++++-------------------------
 runtime/stat.c               |  8 --------
 2 files changed, 5 insertions(+), 33 deletions(-)

diff --git a/runtime/linux/stat_runtime.h b/runtime/linux/stat_runtime.h
index bded327ed..edb239ae5 100644
--- a/runtime/linux/stat_runtime.h
+++ b/runtime/linux/stat_runtime.h
@@ -21,9 +21,6 @@
 #endif
 #define STAT_PUT_CPU()		do {} while (0)
 
-#define _stp_stat_get_agg(stat) ((stat)->agg)
-#define _stp_stat_per_cpu_ptr(stat, cpu) *per_cpu_ptr((stat)->sd, (cpu))
-
 /** Stat struct. Maps do not need this */
 typedef struct _Stat {
 	struct _Hist hist;
@@ -32,15 +29,12 @@ typedef struct _Stat {
 	stat_data *agg;
 
 	/* The stat data is per-cpu data.  */
-	stat_data **sd;
+	stat_data *sd;
 } *Stat;
 
-static void _stp_stat_free(Stat st);
-
 static Stat _stp_stat_alloc(size_t stat_data_size)
 {
 	Stat st;
-	unsigned int cpu;
 
 	if (stat_data_size < sizeof(stat_data))
 		return NULL;
@@ -56,40 +50,26 @@ static Stat _stp_stat_alloc(size_t stat_data_size)
 		return NULL;
 	}
 
-	st->sd = _stp_alloc_percpu (sizeof (stat_data *));
+	st->sd = _stp_alloc_percpu (stat_data_size);
 	if (st->sd == NULL) {
 		_stp_kfree (st->agg);
 		_stp_kfree (st);
 		return NULL;
 	}
 
-	for_each_online_cpu(cpu) {
-		stat_data *sd = _stp_vzalloc_node(stat_data_size,
-						  cpu_to_node(cpu));
-		if (unlikely(sd == NULL)) {
-			_stp_stat_free (st);
-			return NULL;
-		}
-		*per_cpu_ptr(st->sd, cpu) = sd;
-	}
-
 	return st;
 }
 
 static void _stp_stat_free(Stat st)
 {
 	if (st) {
-		unsigned int cpu;
-
-		for_each_possible_cpu(cpu) {
-			stat_data *sd = _stp_stat_per_cpu_ptr(st, cpu);
-			if (likely(sd))
-				_stp_vfree (sd);
-		}
 		_stp_free_percpu (st->sd);
 		_stp_kfree (st->agg);
 		_stp_kfree (st);
 	}
 }
 
+#define _stp_stat_get_agg(stat) ((stat)->agg)
+#define _stp_stat_per_cpu_ptr(stat, cpu) per_cpu_ptr((stat)->sd, (cpu))
+
 #endif /* _LINUX_STAT_RUNTIME_H_ */
diff --git a/runtime/stat.c b/runtime/stat.c
index 8a91b0203..7fc8ac525 100644
--- a/runtime/stat.c
+++ b/runtime/stat.c
@@ -149,8 +149,6 @@ static inline void _stp_stat_add (Stat st, int64_t val, int stat_op_count,
 				  int stat_op_max, int stat_op_variance)
 {
 	stat_data *sd = _stp_stat_per_cpu_ptr (st, STAT_GET_CPU());
-	if (unlikely(sd == NULL))
-		return;
 	STAT_LOCK(sd);
 	__stp_stat_add (&st->hist, sd, val, stat_op_count, stat_op_sum,
 	                stat_op_min, stat_op_max, stat_op_variance);
@@ -190,8 +188,6 @@ static stat_data *_stp_stat_get (Stat st, int clear)
 
 	for_each_possible_cpu(i) {
 		stat_data *sd = _stp_stat_per_cpu_ptr (st, i);
-		if (unlikely(sd == NULL))
-			continue;
 		STAT_LOCK(sd);
 		if (sd->count) {
 			agg->shift = sd->shift;
@@ -224,8 +220,6 @@ static stat_data *_stp_stat_get (Stat st, int clear)
 	 */
 	for_each_possible_cpu(i) {
 		sd = _stp_stat_per_cpu_ptr (st, i);
-		if (unlikely(sd == NULL))
-			continue;
 		STAT_LOCK(sd);
 		if (sd->count) {
 			S1 += sd->count * (sd->avg_s - agg->avg_s) * (sd->avg_s - agg->avg_s);
@@ -269,8 +263,6 @@ static void _stp_stat_clear (Stat st)
 
 	for_each_possible_cpu(i) {
 		stat_data *sd = _stp_stat_per_cpu_ptr (st, i);
-		if (unlikely(sd == NULL))
-			continue;
 		STAT_LOCK(sd);
 		_stp_stat_clear_data (st, sd);
 		STAT_UNLOCK(sd);
-- 
2.43.5