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authorLinus Torvalds <torvalds@linux-foundation.org>2021-01-26 10:39:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-01-26 10:39:46 -0800
commit377bf660d07a47269510435d11f3b65d53edca20 (patch)
treead3c14b6308e71c2762121f6ef99716e8d72c8c1 /mm/page_alloc.c
parent13391c60da3308ed9980de0168f74cce6c62ac1d (diff)
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 <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>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c84
1 files 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)