From 31cf0dd94509eb61e7242e217aea9604621f6b6d Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 23 Apr 2025 14:33:43 +0100 Subject: [PATCH] mm/mm_init: use for_each_valid_pfn() in init_unavailable_range() Currently, memmap_init initializes pfn_hole with 0 instead of ARCH_PFN_OFFSET. Then init_unavailable_range will start iterating each page from the page at address zero to the first available page, but it won't do anything for pages below ARCH_PFN_OFFSET because pfn_valid won't pass. If ARCH_PFN_OFFSET is very large (e.g., something like 2^64-2GiB if the kernel is used as a library and loaded at a very high address), the pointless iteration for pages below ARCH_PFN_OFFSET will take a very long time, and the kernel will look stuck at boot time. Use for_each_valid_pfn() to skip the pointless iterations. Link: https://lkml.kernel.org/r/20250423133821.789413-8-dwmw2@infradead.org Signed-off-by: David Woodhouse Reported-by: Ruihan Li Suggested-by: Mike Rapoport Reviewed-by: Mike Rapoport (Microsoft) Tested-by: Ruihan Li Tested-by: Lorenzo Stoakes Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: David Hildenbrand Cc: Marc Rutland Cc: Marc Zyngier Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/mm_init.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index 7191703a5820c..1c5444e188f82 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -851,11 +851,7 @@ static void __init init_unavailable_range(unsigned long spfn, unsigned long pfn; u64 pgcnt = 0; - for (pfn = spfn; pfn < epfn; pfn++) { - if (!pfn_valid(pageblock_start_pfn(pfn))) { - pfn = pageblock_end_pfn(pfn) - 1; - continue; - } + for_each_valid_pfn(pfn, spfn, epfn) { __init_single_page(pfn_to_page(pfn), pfn, zone, node); __SetPageReserved(pfn_to_page(pfn)); pgcnt++; -- 2.39.5