free_area_init() is responsible for initializing pgdat and zone state.
Calling sparse_init() from there mixes in later vmemmap and struct page
setup, which makes the initialization flow less clear.

Defer sparse_init(), sparse_vmemmap_init_nid_late(), and memmap_init()
until after free_area_init() completes, when zone initialization is fully
done. This keeps free_area_init() focused on zone setup and ensures that
sparse_init() runs with the relevant zone state already available.

This is also a prerequisite for later hugetlb vmemmap changes that need
zone information during early sparse vmemmap setup.

Signed-off-by: Muchun Song <[email protected]>
Reviewed-by: Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by: Oscar Salvador (SUSE) <[email protected]>
---
 mm/mm_init.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index dbcd60a38c49..bdeaceadb531 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1814,7 +1814,6 @@ static void __init free_area_init(void)
        bool descending;
 
        arch_zone_limits_init(max_zone_pfn);
-       sparse_init();
 
        start_pfn = PHYS_PFN(memblock_start_of_DRAM());
        descending = arch_has_descending_max_zone_pfns();
@@ -1903,11 +1902,7 @@ static void __init free_area_init(void)
                }
        }
 
-       for_each_node_state(nid, N_MEMORY)
-               sparse_vmemmap_init_nid_late(nid);
-
        calc_nr_kernel_pages();
-       memmap_init();
 
        /* disable hash distribution for systems with a single node */
        fixup_hashdist();
@@ -2679,10 +2674,17 @@ void __init __weak mem_init(void)
 
 void __init mm_core_init_early(void)
 {
+       int nid;
+
        hugetlb_cma_reserve();
        hugetlb_bootmem_alloc();
 
        free_area_init();
+
+       sparse_init();
+       for_each_node_state(nid, N_MEMORY)
+               sparse_vmemmap_init_nid_late(nid);
+       memmap_init();
 }
 
 /*
-- 
2.54.0


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