VisionFive2 Linux kernel

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 248e2ba4ac59..b80fb8164fb8 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -752,11 +752,44 @@ static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
 #endif /* CONFIG_CMA */
 	}
 }
+struct auto_movable_group_stats {
+	unsigned long movable_pages;
+	unsigned long req_kernel_early_pages;
+};
 
-static bool auto_movable_can_online_movable(int nid, unsigned long nr_pages)
+static int auto_movable_stats_account_group(struct memory_group *group,
+					   void *arg)
+{
+	const int ratio = READ_ONCE(auto_movable_ratio);
+	struct auto_movable_group_stats *stats = arg;
+	long pages;
+
+	/*
+	 * We don't support modifying the config while the auto-movable online
+	 * policy is already enabled. Just avoid the division by zero below.
+	 */
+	if (!ratio)
+		return 0;
+
+	/*
+	 * Calculate how many early kernel pages this group requires to
+	 * satisfy the configured zone ratio.
+	 */
+	pages = group->present_movable_pages * 100 / ratio;
+	pages -= group->present_kernel_pages;
+
+	if (pages > 0)
+		stats->req_kernel_early_pages += pages;
+	stats->movable_pages += group->present_movable_pages;
+	return 0;
+}
+
+static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
+					    unsigned long nr_pages)
 {
-	struct auto_movable_stats stats = {};
 	unsigned long kernel_early_pages, movable_pages;
+	struct auto_movable_group_stats group_stats = {};
+	struct auto_movable_stats stats = {};
 	pg_data_t *pgdat = NODE_DATA(nid);
 	struct zone *zone;
 	int i;
@@ -777,6 +810,21 @@ static bool auto_movable_can_online_movable(int nid, unsigned long nr_pages)
 	kernel_early_pages = stats.kernel_early_pages;
 	movable_pages = stats.movable_pages;
 
+	/*
+	 * Kernel memory inside dynamic memory group allows for more MOVABLE
+	 * memory within the same group. Remove the effect of all but the
+	 * current group from the stats.
+	 */
+	walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
+				   group, &group_stats);
+	if (kernel_early_pages <= group_stats.req_kernel_early_pages)
+		return false;
+	kernel_early_pages -= group_stats.req_kernel_early_pages;
+	movable_pages -= group_stats.movable_pages;
+
+	if (group && group->is_dynamic)
+		kernel_early_pages += group->present_kernel_pages;
+
 	/*
 	 * Test if we could online the given number of pages to ZONE_MOVABLE
 	 * and still stay in the configured ratio.
@@ -834,6 +882,10 @@ static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn
  *    with unmovable allocations). While there are corner cases where it might
  *    still work, it is barely relevant in practice.
  *
+ * Exceptions are dynamic memory groups, which allow for more MOVABLE
+ * memory within the same memory group -- because in that case, there is
+ * coordination within the single memory device managed by a single driver.
+ *
  * We rely on "present pages" instead of "managed pages", as the latter is
  * highly unreliable and dynamic in virtualized environments, and does not
  * consider boot time allocations. For example, memory ballooning adjusts the
@@ -899,12 +951,12 @@ static struct zone *auto_movable_zone_for_pfn(int nid,
 	 * nobody interferes, all will be MOVABLE if possible.
 	 */
 	nr_pages = max_pages - online_pages;
-	if (!auto_movable_can_online_movable(NUMA_NO_NODE, nr_pages))
+	if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
 		goto kernel_zone;
 
 #ifdef CONFIG_NUMA
 	if (auto_movable_numa_aware &&
-	    !auto_movable_can_online_movable(nid, nr_pages))
+	    !auto_movable_can_online_movable(nid, group, nr_pages))
 		goto kernel_zone;
 #endif /* CONFIG_NUMA */