From 3f9688899f7bbf81f6cc3aa1198b1703c49dc9b5 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Thu, 31 Dec 2020 22:04:12 +0000 Subject: [PATCH] mm: memblock: enforce overlap of memory.memblock and memory.reserved Patch series "mm: fix initialization of struct page for holes in memory layout", v2. Commit 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that check each PFN") exposed several issues with the memory map initialization and these patches fix those issues. Initially there were crashes during compaction that Qian Cai reported back in April [1]. It seemed back then that the probelm was fixed, but a few weeks ago Andrea Arcangeli hit the same bug [2] and after a long discussion between us [3] I think these patches are the proper fix. [1] https://lore.kernel.org/lkml/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw [2] https://lore.kernel.org/lkml/20201121194506.13464-1-aarcange@redhat.com [3] https://lore.kernel.org/mm-commits/20201206005401.qKuAVgOXr%akpm@linux-foundation.org This patch (of 2): memblock does not require that the reserved memory ranges will be a subset of memblock.memory. As a result there may be reserved pages that are not in the range of any zone or node because zone and node boundaries are detected based on memblock.memory and pages that only present in memblock.reserved are not taken into account during zone/node size detection. Make sure that all ranges in memblock.reserved are added to memblock.memory before calculating node and zone boundaries. Link: https://lkml.kernel.org/r/20201209214304.6812-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20201209214304.6812-2-rppt@kernel.org Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that check each PFN") Signed-off-by: Mike Rapoport Reported-by: Andrea Arcangeli Cc: Baoquan He Cc: David Hildenbrand Cc: Mel Gorman Cc: Michal Hocko Cc: Qian Cai Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- include/linux/memblock.h | 1 + mm/memblock.c | 24 ++++++++++++++++++++++++ mm/page_alloc.c | 7 +++++++ 3 files changed, 32 insertions(+) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index b93c44b9121e..9c5cc95c7cee 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -120,6 +120,7 @@ int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); unsigned long memblock_free_all(void); void reset_node_managed_pages(pg_data_t *pgdat); void reset_all_zones_managed_pages(void); +void memblock_enforce_memory_reserved_overlap(void); /* Low level functions */ void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags, diff --git a/mm/memblock.c b/mm/memblock.c index d24bcfa88d2f..b8b7be0561c4 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1860,6 +1860,30 @@ void __init_memblock memblock_trim_memory(phys_addr_t align) } } +/** + * memblock_enforce_memory_reserved_overlap - make sure every range in + * @memblock.reserved is covered by @memblock.memory + * + * The data in @memblock.memory is used to detect zone and node boundaries + * during initialization of the memory map and the page allocator. Make + * sure that every memory range present in @memblock.reserved is also added + * to @memblock.memory even if the architecture specific memory + * initialization failed to do so + */ +void __init memblock_enforce_memory_reserved_overlap(void) +{ + phys_addr_t start, end; + int nid; + u64 i; + + __for_each_mem_range(i, &memblock.reserved, &memblock.memory, + NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, &nid) { + pr_warn("memblock: reserved range [%pa-%pa] is not in memory\n", + &start, &end); + memblock_add_node(start, (end - start), nid); + } +} + void __init_memblock memblock_set_current_limit(phys_addr_t limit) { memblock.current_limit = limit; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 23ceaf8fdf55..85f27bf2bbef 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7513,6 +7513,13 @@ void __init free_area_init(unsigned long *max_zone_pfn) memset(arch_zone_highest_possible_pfn, 0, sizeof(arch_zone_highest_possible_pfn)); + /* + * Some architectures (e.g. x86) have reserved pages outside of + * memblock.memory. Make sure these pages are taken into account + * when detecting zone and node boundaries + */ + memblock_enforce_memory_reserved_overlap(); + start_pfn = find_min_pfn_with_active_regions(); descending = arch_has_descending_max_zone_pfns(); -- 2.50.1