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Revert "mm: fix initialization of struct page for holes in memory layout"

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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 <chris@chris-wilson.co.uk>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2021-01-26 10:39:46 -08:00
parent 13391c60da
commit 377bf660d0
1 changed files with 34 additions and 50 deletions
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84
mm/page_alloc.c
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@ -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 * Initialize all valid struct pages in the range [spfn, epfn) and mark them
* PageReserved(). Return the number of struct pages that were initialized. * PageReserved(). Return the number of struct pages that were initialized.
*/ */
static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn, static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
int zone, int nid)
{ {
unsigned long pfn, zone_spfn, zone_epfn; unsigned long pfn;
u64 pgcnt = 0; 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++) { for (pfn = spfn; pfn < epfn; pfn++) {
if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) { if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
pfn = ALIGN_DOWN(pfn, pageblock_nr_pages) pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
+ pageblock_nr_pages - 1; + pageblock_nr_pages - 1;
continue; 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)); __SetPageReserved(pfn_to_page(pfn));
pgcnt++; 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 * Only struct pages that are backed by physical memory are zeroed and
* are zeroed and initialized by going through __init_single_page() during * initialized by going through __init_single_page(). But, there are some
* memmap_init(). * 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.
* *
* But, there could be struct pages that correspond to holes in * This function also addresses a similar issue where struct pages are left
* memblock.memory. This can happen because of the following reasons: * uninitialized because the physical address range is not covered by
* - phyiscal memory bank size is not necessarily the exact multiple of the * memblock.memory or memblock.reserved. That could happen when memblock
* arbitrary section size * layout is manually configured via memmap=, or when the highest physical
* - early reserved memory may not be listed in memblock.memory * address (max_pfn) does not end on a section boundary.
* - memory layouts defined with memmap= kernel parameter may not align
* nicely with memmap sections
*
* 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
*/ */
static void __init init_zone_unavailable_mem(int zone) static void __init init_unavailable_mem(void)
{ {
unsigned long start, end; phys_addr_t start, end;
int i, nid; u64 i, pgcnt;
u64 pgcnt; phys_addr_t next = 0;
unsigned long next = 0;
/* /*
* Loop through holes in memblock.memory and initialize struct * Loop through unavailable ranges not covered by memblock.memory.
* pages corresponding to these holes
*/ */
pgcnt = 0; pgcnt = 0;
for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) { for_each_mem_range(i, &start, &end) {
if (next < start) if (next < start)
pgcnt += init_unavailable_range(next, start, zone, nid); pgcnt += init_unavailable_range(PFN_DOWN(next),
PFN_UP(start));
next = end; next = end;
} }
/* /*
* Last section may surpass the actual end of memory (e.g. we can * Early sections always have a fully populated memmap for the whole
* have 1Gb section and 512Mb of RAM pouplated). * section - see pfn_valid(). If the last section has holes at the
* Make sure that memmap has a well defined state in this case. * 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(PFN_DOWN(next),
pgcnt += init_unavailable_range(next, end, zone, nid); round_up(max_pfn, PAGES_PER_SECTION));
/* /*
* Struct pages that do not have backing memory. This could be because * Struct pages that do not have backing memory. This could be because
* firmware is using some of this memory, or for some other reasons. * firmware is using some of this memory, or for some other reasons.
*/ */
if (pgcnt) if (pgcnt)
pr_info("Zone %s: zeroed struct page in unavailable ranges: %lld pages", zone_names[zone], pgcnt); pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
}
static void __init init_unavailable_mem(void)
{
int zone;
for (zone = 0; zone < ZONE_MOVABLE; zone++)
init_zone_unavailable_mem(zone);
} }
#else #else
static inline void __init init_unavailable_mem(void) static inline void __init init_unavailable_mem(void)