[PATCH v10 00/10] complete deferred page initialization

From: Pavel Tatashin
Date: Thu Oct 05 2017 - 17:16:33 EST

v10 - v9
- Addressed new comments from Michal Hocko.
- Sent "mm: deferred_init_memmap improvements" as a separate patch as
it is also fixing existing problem.
- Merged "mm: stop zeroing memory during allocation in vmemmap" with
"mm: zero struct pages during initialization".
- Added more comments "mm: zero reserved and unavailable struct pages"

v9 - v8
- Addressed comments raised by Mark Rutland and Ard Biesheuvel: changed
kasan implementation. Added a new function: kasan_map_populate() that
zeroes the allocated and mapped memory

v8 - v7
- Added Acked-by's from Dave Miller for SPARC changes
- Fixed a minor compiling issue on tile architecture reported by kbuild

v7 - v6
- Addressed comments from Michal Hocko
- memblock_discard() patch was removed from this series and integrated
- Fixed bug reported by kbuild test robot new patch:
mm: zero reserved and unavailable struct pages
- Removed patch
x86/mm: reserve only exiting low pages
As, it is not needed anymore, because of the previous fix
- Re-wrote deferred_init_memmap(), found and fixed an existing bug, where
page variable is not reset when zone holes present.
- Merged several patches together per Michal request
- Added performance data including raw logs

v6 - v5
- Fixed ARM64 + kasan code, as reported by Ard Biesheuvel
- Tested ARM64 code in qemu and found few more issues, that I fixed in this
- Added page roundup/rounddown to x86 and arm zeroing routines to zero the
whole allocated range, instead of only provided address range.
- Addressed SPARC related comment from Sam Ravnborg
- Fixed section mismatch warnings related to memblock_discard().

v5 - v4
- Fixed build issues reported by kbuild on various configurations
v4 - v3
- Rewrote code to zero sturct pages in __init_single_page() as
suggested by Michal Hocko
- Added code to handle issues related to accessing struct page
memory before they are initialized.

v3 - v2
- Addressed David Miller comments about one change per patch:
* Splited changes to platforms into 4 patches
* Made "do not zero vmemmap_buf" as a separate patch

v2 - v1
- Per request, added s390 to deferred "struct page" zeroing
- Collected performance data on x86 which proofs the importance to
keep memset() as prefetch (see below).

SMP machines can benefit from the DEFERRED_STRUCT_PAGE_INIT config option,
which defers initializing struct pages until all cpus have been started so
it can be done in parallel.

However, this feature is sub-optimal, because the deferred page
initialization code expects that the struct pages have already been zeroed,
and the zeroing is done early in boot with a single thread only. Also, we
access that memory and set flags before struct pages are initialized. All
of this is fixed in this patchset.

In this work we do the following:
- Never read access struct page until it was initialized
- Never set any fields in struct pages before they are initialized
- Zero struct page at the beginning of struct page initialization

Performance improvements on x86 machine with 8 nodes:
Intel(R) Xeon(R) CPU E7-8895 v3 @ 2.60GHz and 1T of memory:
base no deferred: 95.796233s
fix no deferred: 79.978956s 19.77%

base deferred: 77.254713s
fix deferred: 55.050509s 40.34%
SPARC M6 3600 MHz with 15T of memory
base no deferred: 358.335727s
fix no deferred: 302.320936s 18.52%

base deferred: 237.534603s
fix deferred: 182.103003s 30.44%
Raw dmesg output with timestamps:
x86 base no deferred: https://hastebin.com/ofunepurit.scala
x86 base deferred: https://hastebin.com/ifazegeyas.scala
x86 fix no deferred: https://hastebin.com/pegocohevo.scala
x86 fix deferred: https://hastebin.com/ofupevikuk.scala
sparc base no deferred: https://hastebin.com/ibobeteken.go
sparc base deferred: https://hastebin.com/fariqimiyu.go
sparc fix no deferred: https://hastebin.com/muhegoheyi.go
sparc fix deferred: https://hastebin.com/xadinobutu.go

Pavel Tatashin (10):
x86/mm: setting fields in deferred pages
sparc64/mm: setting fields in deferred pages
sparc64: simplify vmemmap_populate
mm: defining memblock_virt_alloc_try_nid_raw
mm: zero reserved and unavailable struct pages
mm/kasan: kasan specific map populate function
x86/kasan: use kasan_map_populate()
arm64/kasan: use kasan_map_populate()
mm: stop zeroing memory during allocation in vmemmap
sparc64: optimized struct page zeroing

arch/arm64/include/asm/pgtable.h | 3 ++
arch/arm64/mm/kasan_init.c | 12 +++----
arch/sparc/include/asm/pgtable_64.h | 30 +++++++++++++++++
arch/sparc/mm/init_64.c | 32 ++++++++----------
arch/x86/mm/init_64.c | 10 ++++--
arch/x86/mm/kasan_init_64.c | 8 ++---
include/linux/bootmem.h | 27 +++++++++++++++
include/linux/kasan.h | 2 ++
include/linux/memblock.h | 16 +++++++++
include/linux/mm.h | 26 ++++++++++++++
mm/kasan/kasan_init.c | 67 +++++++++++++++++++++++++++++++++++++
mm/memblock.c | 60 +++++++++++++++++++++++++++++----
mm/page_alloc.c | 54 +++++++++++++++++++++++++-----
mm/sparse-vmemmap.c | 15 ++++-----
mm/sparse.c | 6 ++--
15 files changed, 312 insertions(+), 56 deletions(-)