quoted

We should do something like:

diff --git a/mm/memblock.c b/mm/memblock.c
index 154f1d73b61f2..ed4c563d72c32 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c

@@ -1091,13 +1091,16 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
  /**
   * memblock_reserved_mark_noinit - Mark a reserved memory region with flag
- * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized
- * for this region.
+ * MEMBLOCK_RSRV_NOINIT which allows for the "struct pages" corresponding
+ * to this region not getting initialized, because the caller will take
+ * care of it.
   * @base: the base phys addr of the region
   * @size: the size of the region
   *
- * struct pages will not be initialized for reserved memory regions marked with
- * %MEMBLOCK_RSRV_NOINIT.
+ * "struct pages" will not be initialized for reserved memory regions marked
+ * with %MEMBLOCK_RSRV_NOINIT if this function is called before initialization
+ * code runs. Without CONFIG_DEFERRED_STRUCT_PAGE_INIT, it is more likely
+ * that this function is not effective.
   *
   * Return: 0 on success, -errno on failure.
   */

I have a different version :)
  

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index b96746376e17..d20d091c6343 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h

@@ -40,8 +40,9 @@ extern unsigned long long max_possible_pfn;
   * via a driver, and never indicated in the firmware-provided memory map as
   * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the
   * kernel resource tree.
- * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are
- * not initialized (only for reserved regions).
+ * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages don't have
+ * PG_Reserved set and are completely not initialized when
+ * %CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled (only for reserved regions).
   * @MEMBLOCK_RSRV_KERN: memory region that is reserved for kernel use,
   * either explictitly with memblock_reserve_kern() or via memblock
   * allocation APIs. All memblock allocations set this flag.

diff --git a/mm/memblock.c b/mm/memblock.c
index 154f1d73b61f..02de5ffb085b 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c

@@ -1091,13 +1091,15 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
  
  /**
   * memblock_reserved_mark_noinit - Mark a reserved memory region with flag
- * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized
- * for this region.
+ * MEMBLOCK_RSRV_NOINIT
+ *
   * @base: the base phys addr of the region
   * @size: the size of the region
   *
- * struct pages will not be initialized for reserved memory regions marked with
- * %MEMBLOCK_RSRV_NOINIT.
+ * The struct pages for the reserved regions marked %MEMBLOCK_RSRV_NOINIT will
+ * not have %PG_Reserved flag set.
+ * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, setting this flags also
+ * completly bypasses the initialization of struct pages for this region.