[PATCH v3 0/2] mm: fix initialization of struct page for holes in memory layout

Mike Rapoport
2021-01-11T19:41:09Z

From: Mike Rapoport <rppt@linux.ibm.com>

Hi,

Commit 73a6e474cb37 ("mm: memmap_init: iterate over
memblock regions rather that check each PFN") exposed several issues with
the memory map initialization and these patches fix those issues.

Initially there were crashes during compaction that Qian Cai reported back
in April [1]. It seemed back then that the problem was fixed, but a few
weeks ago Andrea Arcangeli hit the same bug [2] and there was an additional
discussion at [3].

v3:
* use architectural zone constraints to set zone links for struct pages
corresponding to the holes
* drop implicit update of memblock.memory
* add a patch that sets pfn 0 to E820_TYPE_RAM on x86

v2: https://lore.kernel.org/lkml/20201209214304.6812-1-rppt@kernel.org/):
* added patch that adds all regions in memblock.reserved that do not
overlap with memblock.memory to memblock.memory in the beginning of
free_area_init()

[1] https://lore.kernel.org/lkml/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw
[2] https://lore.kernel.org/lkml/20201121194506.13464-1-aarcange@redhat.com
[3] https://lore.kernel.org/mm-commits/20201206005401.qKuAVgOXr%akpm@linux-foundation.org

Mike Rapoport (2):
x86/setup: don't remove E820_TYPE_RAM for pfn 0
mm: fix initialization of struct page for holes in memory layout

arch/x86/kernel/setup.c | 20 +++++-----
mm/page_alloc.c | 84 ++++++++++++++++++++++++-----------------
2 files changed, 59 insertions(+), 45 deletions(-)

--
2.28.0