From 377bf660d07a47269510435d11f3b65d53edca20 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 26 Jan 2021 10:39:46 -0800 Subject: Revert "mm: fix initialization of struct page for holes in memory layout" This reverts commit d3921cb8be29ce5668c64e23ffdaeec5f8c69399. Chris Wilson reports that it causes boot problems: "We have half a dozen or so different machines in CI that are silently failing to boot, that we believe is bisected to this patch" and the CI team confirmed that a revert fixed the issues. The cause is unknown for now, so let's revert it. Link: https://lore.kernel.org/lkml/161160687463.28991.354987542182281928@build.alporthouse.com/ Reported-and-tested-by: Chris Wilson Acked-by: Mike Rapoport Cc: Andrea Arcangeli Cc: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 84 +++++++++++++++++++++++---------------------------------- 1 file changed, 34 insertions(+), 50 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 783913e41f65..519a60d5b6f7 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7080,26 +7080,23 @@ void __init free_area_init_memoryless_node(int nid) * Initialize all valid struct pages in the range [spfn, epfn) and mark them * PageReserved(). Return the number of struct pages that were initialized. */ -static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn, - int zone, int nid) +static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn) { - unsigned long pfn, zone_spfn, zone_epfn; + unsigned long pfn; u64 pgcnt = 0; - zone_spfn = arch_zone_lowest_possible_pfn[zone]; - zone_epfn = arch_zone_highest_possible_pfn[zone]; - - spfn = clamp(spfn, zone_spfn, zone_epfn); - epfn = clamp(epfn, zone_spfn, zone_epfn); - for (pfn = spfn; pfn < epfn; pfn++) { if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) { pfn = ALIGN_DOWN(pfn, pageblock_nr_pages) + pageblock_nr_pages - 1; continue; } - - __init_single_page(pfn_to_page(pfn), pfn, zone, nid); + /* + * Use a fake node/zone (0) for now. Some of these pages + * (in memblock.reserved but not in memblock.memory) will + * get re-initialized via reserve_bootmem_region() later. + */ + __init_single_page(pfn_to_page(pfn), pfn, 0, 0); __SetPageReserved(pfn_to_page(pfn)); pgcnt++; } @@ -7108,64 +7105,51 @@ static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn, } /* - * Only struct pages that correspond to ranges defined by memblock.memory - * are zeroed and initialized by going through __init_single_page() during - * memmap_init(). - * - * But, there could be struct pages that correspond to holes in - * memblock.memory. This can happen because of the following reasons: - * - phyiscal memory bank size is not necessarily the exact multiple of the - * arbitrary section size - * - early reserved memory may not be listed in memblock.memory - * - memory layouts defined with memmap= kernel parameter may not align - * nicely with memmap sections + * Only struct pages that are backed by physical memory are zeroed and + * initialized by going through __init_single_page(). But, there are some + * struct pages which are reserved in memblock allocator and their fields + * may be accessed (for example page_to_pfn() on some configuration accesses + * flags). We must explicitly initialize those struct pages. * - * Explicitly initialize those struct pages so that: - * - PG_Reserved is set - * - zone link is set accorging to the architecture constrains - * - node is set to node id of the next populated region except for the - * trailing hole where last node id is used + * This function also addresses a similar issue where struct pages are left + * uninitialized because the physical address range is not covered by + * memblock.memory or memblock.reserved. That could happen when memblock + * layout is manually configured via memmap=, or when the highest physical + * address (max_pfn) does not end on a section boundary. */ -static void __init init_zone_unavailable_mem(int zone) +static void __init init_unavailable_mem(void) { - unsigned long start, end; - int i, nid; - u64 pgcnt; - unsigned long next = 0; + phys_addr_t start, end; + u64 i, pgcnt; + phys_addr_t next = 0; /* - * Loop through holes in memblock.memory and initialize struct - * pages corresponding to these holes + * Loop through unavailable ranges not covered by memblock.memory. */ pgcnt = 0; - for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) { + for_each_mem_range(i, &start, &end) { if (next < start) - pgcnt += init_unavailable_range(next, start, zone, nid); + pgcnt += init_unavailable_range(PFN_DOWN(next), + PFN_UP(start)); next = end; } /* - * Last section may surpass the actual end of memory (e.g. we can - * have 1Gb section and 512Mb of RAM pouplated). - * Make sure that memmap has a well defined state in this case. + * Early sections always have a fully populated memmap for the whole + * section - see pfn_valid(). If the last section has holes at the + * end and that section is marked "online", the memmap will be + * considered initialized. Make sure that memmap has a well defined + * state. */ - end = round_up(max_pfn, PAGES_PER_SECTION); - pgcnt += init_unavailable_range(next, end, zone, nid); + pgcnt += init_unavailable_range(PFN_DOWN(next), + round_up(max_pfn, PAGES_PER_SECTION)); /* * Struct pages that do not have backing memory. This could be because * firmware is using some of this memory, or for some other reasons. */ if (pgcnt) - pr_info("Zone %s: zeroed struct page in unavailable ranges: %lld pages", zone_names[zone], pgcnt); -} - -static void __init init_unavailable_mem(void) -{ - int zone; - - for (zone = 0; zone < ZONE_MOVABLE; zone++) - init_zone_unavailable_mem(zone); + pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt); } #else static inline void __init init_unavailable_mem(void) -- cgit v1.2.3