From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Subject: mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE Patch series "mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE". After recent updates to freeing unused parts of the memory map, no architecture can have holes in the memory map within a pageblock. This makes pfn_valid_within() check and CONFIG_HOLES_IN_ZONE configuration option redundant. The first patch removes them both in a mechanical way and the second patch simplifies memory_hotplug::test_pages_in_a_zone() that had pfn_valid_within() surrounded by more logic than simple if. This patch (of 2): After recent changes in freeing of the unused parts of the memory map and rework of pfn_valid() in arm and arm64 there are no architectures that can have holes in the memory map within a pageblock and so nothing can enable CONFIG_HOLES_IN_ZONE which guards non trivial implementation of pfn_valid_within(). With that, pfn_valid_within() is always hardwired to 1 and can be completely removed. Remove calls to pfn_valid_within() and CONFIG_HOLES_IN_ZONE. Link: https://lkml.kernel.org/r/20210713080035.7464-1-rppt@xxxxxxxxxx Link: https://lkml.kernel.org/r/20210713080035.7464-2-rppt@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/base/node.c | 2 -- include/linux/mmzone.h | 12 ------------ mm/Kconfig | 3 --- mm/compaction.c | 20 +++++++------------- mm/memory_hotplug.c | 4 ---- mm/page_alloc.c | 24 ++---------------------- mm/page_isolation.c | 7 +------ mm/page_owner.c | 14 +------------- 8 files changed, 11 insertions(+), 75 deletions(-) --- a/drivers/base/node.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/drivers/base/node.c @@ -768,8 +768,6 @@ int unregister_cpu_under_node(unsigned i #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE static int __ref get_nid_for_pfn(unsigned long pfn) { - if (!pfn_valid_within(pfn)) - return -1; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT if (system_state < SYSTEM_RUNNING) return early_pfn_to_nid(pfn); --- a/include/linux/mmzone.h~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/include/linux/mmzone.h @@ -1525,18 +1525,6 @@ void sparse_init(void); #define subsection_map_init(_pfn, _nr_pages) do {} while (0) #endif /* CONFIG_SPARSEMEM */ -/* - * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we - * need to check pfn validity within that MAX_ORDER_NR_PAGES block. - * pfn_valid_within() should be used in this case; we optimise this away - * when we have no holes within a MAX_ORDER_NR_PAGES block. - */ -#ifdef CONFIG_HOLES_IN_ZONE -#define pfn_valid_within(pfn) pfn_valid(pfn) -#else -#define pfn_valid_within(pfn) (1) -#endif - #endif /* !__GENERATING_BOUNDS.H */ #endif /* !__ASSEMBLY__ */ #endif /* _LINUX_MMZONE_H */ --- a/mm/compaction.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/compaction.c @@ -306,16 +306,14 @@ __reset_isolation_pfn(struct zone *zone, * is necessary for the block to be a migration source/target. */ do { - if (pfn_valid_within(pfn)) { - if (check_source && PageLRU(page)) { - clear_pageblock_skip(page); - return true; - } + if (check_source && PageLRU(page)) { + clear_pageblock_skip(page); + return true; + } - if (check_target && PageBuddy(page)) { - clear_pageblock_skip(page); - return true; - } + if (check_target && PageBuddy(page)) { + clear_pageblock_skip(page); + return true; } page += (1 << PAGE_ALLOC_COSTLY_ORDER); @@ -585,8 +583,6 @@ static unsigned long isolate_freepages_b break; nr_scanned++; - if (!pfn_valid_within(blockpfn)) - goto isolate_fail; /* * For compound pages such as THP and hugetlbfs, we can save @@ -885,8 +881,6 @@ isolate_migratepages_block(struct compac cond_resched(); } - if (!pfn_valid_within(low_pfn)) - goto isolate_fail; nr_scanned++; page = pfn_to_page(low_pfn); --- a/mm/Kconfig~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/Kconfig @@ -96,9 +96,6 @@ config HAVE_FAST_GUP depends on MMU bool -config HOLES_IN_ZONE - bool - # Don't discard allocated memory used to track "memory" and "reserved" memblocks # after early boot, so it can still be used to test for validity of memory. # Also, memblocks are updated with memory hot(un)plug. --- a/mm/memory_hotplug.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/memory_hotplug.c @@ -1308,10 +1308,6 @@ struct zone *test_pages_in_a_zone(unsign for (; pfn < sec_end_pfn && pfn < end_pfn; pfn += MAX_ORDER_NR_PAGES) { i = 0; - /* This is just a CONFIG_HOLES_IN_ZONE check.*/ - while ((i < MAX_ORDER_NR_PAGES) && - !pfn_valid_within(pfn + i)) - i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; /* Check if we got outside of the zone */ --- a/mm/page_alloc.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/page_alloc.c @@ -594,8 +594,6 @@ static int page_outside_zone_boundaries( static int page_is_consistent(struct zone *zone, struct page *page) { - if (!pfn_valid_within(page_to_pfn(page))) - return 0; if (zone != page_zone(page)) return 0; @@ -1025,16 +1023,12 @@ buddy_merge_likely(unsigned long pfn, un if (order >= MAX_ORDER - 2) return false; - if (!pfn_valid_within(buddy_pfn)) - return false; - combined_pfn = buddy_pfn & pfn; higher_page = page + (combined_pfn - pfn); buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); higher_buddy = higher_page + (buddy_pfn - combined_pfn); - return pfn_valid_within(buddy_pfn) && - page_is_buddy(higher_page, higher_buddy, order + 1); + return page_is_buddy(higher_page, higher_buddy, order + 1); } /* @@ -1095,8 +1089,6 @@ continue_merging: buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); - if (!pfn_valid_within(buddy_pfn)) - goto done_merging; if (!page_is_buddy(page, buddy, order)) goto done_merging; /* @@ -1754,9 +1746,7 @@ void __init memblock_free_pages(struct p /* * Check that the whole (or subset of) a pageblock given by the interval of * [start_pfn, end_pfn) is valid and within the same zone, before scanning it - * with the migration of free compaction scanner. The scanners then need to - * use only pfn_valid_within() check for arches that allow holes within - * pageblocks. + * with the migration of free compaction scanner. * * Return struct page pointer of start_pfn, or NULL if checks were not passed. * @@ -1872,8 +1862,6 @@ static inline void __init pgdat_init_rep */ static inline bool __init deferred_pfn_valid(unsigned long pfn) { - if (!pfn_valid_within(pfn)) - return false; if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn)) return false; return true; @@ -2520,11 +2508,6 @@ static int move_freepages(struct zone *z int pages_moved = 0; for (pfn = start_pfn; pfn <= end_pfn;) { - if (!pfn_valid_within(pfn)) { - pfn++; - continue; - } - page = pfn_to_page(pfn); if (!PageBuddy(page)) { /* @@ -8828,9 +8811,6 @@ struct page *has_unmovable_pages(struct } for (; iter < pageblock_nr_pages - offset; iter++) { - if (!pfn_valid_within(pfn + iter)) - continue; - page = pfn_to_page(pfn + iter); /* --- a/mm/page_isolation.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/page_isolation.c @@ -93,8 +93,7 @@ static void unset_migratetype_isolate(st buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); - if (pfn_valid_within(buddy_pfn) && - !is_migrate_isolate_page(buddy)) { + if (!is_migrate_isolate_page(buddy)) { __isolate_free_page(page, order); isolated_page = true; } @@ -250,10 +249,6 @@ __test_page_isolated_in_pageblock(unsign struct page *page; while (pfn < end_pfn) { - if (!pfn_valid_within(pfn)) { - pfn++; - continue; - } page = pfn_to_page(pfn); if (PageBuddy(page)) /* --- a/mm/page_owner.c~mm-remove-pfn_valid_within-and-config_holes_in_zone +++ a/mm/page_owner.c @@ -276,9 +276,6 @@ void pagetypeinfo_showmixedcount_print(s pageblock_mt = get_pageblock_migratetype(page); for (; pfn < block_end_pfn; pfn++) { - if (!pfn_valid_within(pfn)) - continue; - /* The pageblock is online, no need to recheck. */ page = pfn_to_page(pfn); @@ -479,10 +476,6 @@ read_page_owner(struct file *file, char continue; } - /* Check for holes within a MAX_ORDER area */ - if (!pfn_valid_within(pfn)) - continue; - page = pfn_to_page(pfn); if (PageBuddy(page)) { unsigned long freepage_order = buddy_order_unsafe(page); @@ -560,14 +553,9 @@ static void init_pages_in_zone(pg_data_t block_end_pfn = min(block_end_pfn, end_pfn); for (; pfn < block_end_pfn; pfn++) { - struct page *page; + struct page *page = pfn_to_page(pfn); struct page_ext *page_ext; - if (!pfn_valid_within(pfn)) - continue; - - page = pfn_to_page(pfn); - if (page_zone(page) != zone) continue; _
