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

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This reverts commit d3921cb8be.

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
* 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().
* 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.
*
* 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
*
* 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)