[v2 5/6] mm: move allocation of gigantic hstates to the start of mm_core_init

[Usama Arif <usama.arif@bytedance.com>]

Whether the initialization of tail struct pages of a hugepage
happens or not will become dependent on the commandline
parameter hugetlb_free_vmemmap in the future. Hence,
hugetlb_hstate_alloc_pages needs to be after command line parameters
are parsed and the start of mm_core_init is a good point.

Signed-off-by: Usama Arif <usama.arif@bytedance.com>
---
 mm/hugetlb.c  | 18 ++++++++++--------
 mm/internal.h |  9 +++++++++
 mm/mm_init.c  |  6 ++++++
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 541c07b6d60f..bf60545496d7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4400,14 +4400,6 @@ static int __init hugepages_setup(char *s)
 		}
 	}
 
-	/*
-	 * Global state is always initialized later in hugetlb_init.
-	 * But we need to allocate gigantic hstates here early to still
-	 * use the bootmem allocator.
-	 */
-	if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
-		hugetlb_hstate_alloc_pages(parsed_hstate);
-
 	last_mhp = mhp;
 
 	return 1;
@@ -4419,6 +4411,16 @@ static int __init hugepages_setup(char *s)
 }
 __setup("hugepages=", hugepages_setup);
 
+void __init hugetlb_hstate_alloc_gigantic_pages(void)
+{
+	int i;
+
+	for (i = 0; i < HUGE_MAX_HSTATE; i++) {
+		if (hstate_is_gigantic(&hstates[i]))
+			hugetlb_hstate_alloc_pages(&hstates[i]);
+	}
+}
+
 /*
  * hugepagesz command line processing
  * A specific huge page size can only be specified once with hugepagesz.
diff --git a/mm/internal.h b/mm/internal.h
index a7d9e980429a..692bb1136a39 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1102,4 +1102,13 @@ struct vma_prepare {
 	struct vm_area_struct *remove;
 	struct vm_area_struct *remove2;
 };
+
+#ifdef CONFIG_HUGETLBFS
+void __init hugetlb_hstate_alloc_gigantic_pages(void);
+#else
+static inline void __init hugetlb_hstate_alloc_gigantic_pages(void);
+{
+}
+#endif /* CONFIG_HUGETLBFS */
+
 #endif	/* __MM_INTERNAL_H */
diff --git a/mm/mm_init.c b/mm/mm_init.c
index a1963c3322af..f2751ccd7d99 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -26,6 +26,7 @@
 #include <linux/pgtable.h>
 #include <linux/swap.h>
 #include <linux/cma.h>
+#include <linux/hugetlb.h>
 #include "internal.h"
 #include "slab.h"
 #include "shuffle.h"
@@ -2768,6 +2769,11 @@ static void __init mem_init_print_info(void)
  */
 void __init mm_core_init(void)
 {
+	/*
+	 * We need to allocate gigantic hstates here early to still use the bootmem
+	 * allocator. Non gigantic hstates are initialized later in hugetlb_init.
+	 */
+	hugetlb_hstate_alloc_gigantic_pages();
 	/* Initializations relying on SMP setup */
 	build_all_zonelists(NULL);
 	page_alloc_init_cpuhp();
-- 
2.25.1