@@ -110,6 +110,59 @@ static void memory_block_release(struct device *dev)
kfree(mem);
}
+
+/* Max block size to be set by memory_block_advise_max_size */
+static unsigned long memory_block_advised_size;
+static bool memory_block_advised_size_queried;
+
+/**
+ * memory_block_advise_max_size() - advise memory hotplug on the max suggested
+ * block size, usually for alignment.
+ * @size: suggestion for maximum block size. must be aligned on power of 2.
+ *
+ * Early boot software (pre-allocator init) may advise archs on the max block
+ * size. This value can only decrease after initialization, as the intent is
+ * to identify the largest supported alignment for all sources.
+ *
+ * Use of this value is arch-defined, as is min/max block size.
+ *
+ * Return: 0 on success
+ * -EINVAL if size is 0 or not pow2 aligned
+ * -EBUSY if value has already been probed
+ */
+int __init memory_block_advise_max_size(unsigned long size)
+{
+ if (!size || !is_power_of_2(size))
+ return -EINVAL;
+
+ if (memory_block_advised_size_queried)
+ return -EBUSY;
+
+ if (memory_block_advised_size) {
+ memory_block_advised_size = min(memory_block_advised_size,
+ size);
+ } else {
+ memory_block_advised_size = size;
+ }
+
+ return 0;
+}
+
+/**
+ * memory_block_advised_max_size() - query advised max hotplug block size.
+ *
+ * After the first call, the value can never change. Callers looking for the
+ * actual block size should use memory_block_size_bytes. This interface is
+ * intended for use by arch-init when initializing the hotplug block size.
+ *
+ * Return: advised size in bytes, or 0 if never set.
+ */
+unsigned long memory_block_advised_max_size(void)
+{
+ memory_block_advised_size_queried = true;
+ return memory_block_advised_size;
+}
+
unsigned long __weak memory_block_size_bytes(void)
{
return MIN_MEMORY_BLOCK_SIZE;
@@ -149,6 +149,14 @@ static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
{
return 0;
}
+static inline int memory_block_advise_max_size(unsigned long size)
+{
+ return -ENODEV;
+}
+static inline unsigned long memory_block_advised_max_size(void)
+{
+ return 0;
+}
#else /* CONFIG_MEMORY_HOTPLUG */
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
@@ -181,6 +189,8 @@ int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
void memory_block_add_nid(struct memory_block *mem, int nid,
enum meminit_context context);
#endif /* CONFIG_NUMA */
+int memory_block_advise_max_size(unsigned long size);
+unsigned long memory_block_advised_max_size(void);
#endif /* CONFIG_MEMORY_HOTPLUG */
/*