gcov: Make TOPN counter dynamically allocated

* from gcc-mirror/gcc@871e5ad remove USE_ATOMIC usage use kmalloc instead of xmalloc Signed-off-by: Diaz1401 <[email protected]>
mengkernel · Jun 30, 2023 · 693b194 · 693b194
1 parent 70373f3
commit 693b194
Showing 1 changed file with 68 additions and 29 deletions.
diff --git a/kernel/gcov/gcc_base.c b/kernel/gcov/gcc_base.c
@@ -3,6 +3,7 @@
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
+#include <stdlib.h>
 #include "gcov.h"
 
 /*
@@ -86,8 +87,72 @@ void __gcov_exit(void)
 EXPORT_SYMBOL(__gcov_exit);
 
 #ifdef CONFIG_PGO_KERNEL
-/* Number of top N value histogram. */
-#define GCOV_TOPN_VALUES 4
+
+/* Maximum number of tracked TOP N value profiles.  */
+#define GCOV_TOPN_MAXIMUM_TRACKED_VALUES 32
+
+/* GCOV key-value pair linked list type.  */
+struct gcov_kvp {
+	gcov_type value;
+	gcov_type count;
+	struct gcov_kvp *next;
+};
+
+static inline void gcov_counter_add(gcov_type *counter, gcov_type value)
+{
+	*counter += value;
+}
+
+static inline int gcov_counter_set_if_null(gcov_type *counter, struct gcov_kvp *node)
+{
+	*counter = (intptr_t)node;
+	return 1;
+}
+
+static inline void gcov_topn_add_value(gcov_type *counters, gcov_type value, gcov_type count,
+		     int increment_total)
+{
+	if (increment_total)
+		gcov_counter_add(&counters[0], 1);
+
+	struct gcov_kvp *prev_node = NULL;
+	struct gcov_kvp *minimal_node = NULL;
+	struct gcov_kvp *current_node  = (struct gcov_kvp *)counters[2];
+
+	while (current_node) {
+		if (current_node->value == value) {
+			gcov_counter_add(&current_node->count, count);
+			return;
+		}
+
+		if (minimal_node == NULL  || current_node->count < minimal_node->count)
+			minimal_node = current_node;
+
+		prev_node = current_node;
+		current_node = current_node->next;
+	}
+
+	if (counters[1] == GCOV_TOPN_MAXIMUM_TRACKED_VALUES) {
+		if (--minimal_node->count < count) {
+			minimal_node->value = value;
+			minimal_node->count = count;
+		}
+	} else {
+		struct gcov_kvp *new_node = (struct gcov_kvp *)kmalloc(sizeof(struct gcov_kvp), GFP_KERNEL);
+		new_node->value = value;
+		new_node->count = count;
+
+		int success = 0;
+		if (!counters[2])
+			success = gcov_counter_set_if_null(&counters[2], new_node);
+		else if (prev_node && !prev_node->next)
+			success = gcov_counter_set_if_null((gcov_type *)&prev_node->next, new_node);
+
+		/* Increment number of nodes.  */
+		if (success)
+			gcov_counter_add(&counters[1], 1);
+	}
+}
 
 void __gcov_merge_topn(gcov_type *counters, unsigned int n_counters)
 {
@@ -114,33 +179,7 @@ EXPORT_SYMBOL(__gcov_time_profiler_counter);
 static inline void __gcov_topn_values_profiler_body(gcov_type *counters,
 		gcov_type value)
 {
-	int empty_counter = -1;
-	unsigned int i;
-
-	counters[0]++;
-	++counters;
-
-	/* First try to find an existing value. */
-	for (i = 0; i < GCOV_TOPN_VALUES; i++)
-		if (value == counters[2 * i]) {
-			counters[2 * i + 1] += GCOV_TOPN_VALUES;
-			return;
-		} else if (counters[2 * i + 1] <= 0)
-			empty_counter = i;
-
-	/* Find an empty slot for a new value. */
-	if (empty_counter != -1) {
-		counters[2 * empty_counter] = value;
-		counters[2 * empty_counter + 1] = GCOV_TOPN_VALUES;
-		return;
-	}
-
-	/*
-	 * We haven't found an empty slot, then decrement all
-	 * counter values by one.
-	 */
-	for (i = 0; i < GCOV_TOPN_VALUES; i++)
-		counters[2 * i + 1]--;
+	gcov_topn_add_value(counters, value, 1, 1);
 }
 
 void __gcov_topn_values_profiler(gcov_type *counters, gcov_type value)