lib: net_buf: support counting max used buf

Support counting the max used net_buf when CONFIG_NET_BUF_POOL_USAGE
is defined.

Signed-off-by: Maochen Wang <[email protected]>

Author: MaochenWang1

include/zephyr/net_buf.h

@@ -1098,6 +1098,9 @@ struct net_buf_pool {
 	/** Total size of the pool. */
 	const uint16_t pool_size;
 
+	/** Maximum count of used buffers. */
+	uint16_t max_used;
+
 	/** Name of the pool. Used when printing pool information. */
 	const char *name;
 #endif /* CONFIG_NET_BUF_POOL_USAGE */
@@ -1115,6 +1118,7 @@ struct net_buf_pool {
 /** @cond INTERNAL_HIDDEN */
 #define NET_BUF_POOL_USAGE_INIT(_pool, _count) \
 	IF_ENABLED(CONFIG_NET_BUF_POOL_USAGE, (.avail_count = ATOMIC_INIT(_count),)) \
+	IF_ENABLED(CONFIG_NET_BUF_POOL_USAGE, (.max_used = 0,)) \
 	IF_ENABLED(CONFIG_NET_BUF_POOL_USAGE, (.name = STRINGIFY(_pool),))
 
 #define NET_BUF_POOL_INITIALIZER(_pool, _alloc, _bufs, _count, _ud_size, _destroy) \

lib/net_buf/buf.c

@@ -344,6 +344,8 @@ struct net_buf *net_buf_alloc_len(struct net_buf_pool *pool, size_t size,
 #if defined(CONFIG_NET_BUF_POOL_USAGE)
 	atomic_dec(&pool->avail_count);
 	__ASSERT_NO_MSG(atomic_get(&pool->avail_count) >= 0);
+	pool->max_used = MAX(pool->max_used,
+			     pool->buf_count - atomic_get(&pool->avail_count));
 #endif
 	return buf;
 }