[PATCH v8 00/70] Introducing the Maple Tree

From: Liam Howlett
Date: Tue Apr 26 2022 - 11:07:11 EST


Andrew,

Please replace the patches in your mglru-maple branch with this set. It should
be a drop in replacement for my patch range with the fixes into these
patches. Adding the preallocation to work around the fs-reclaim LOCKDEP
issue caused enough changes to the patches to warrant a respin.

The last patch on the branch is still needed to fix vmscan after mglru
is applied. ee4b1fc24f30 "mm/vmscan: Use VMA_ITERATOR in
get_next_vma()"


Here is the pretty cover letter you requested last time.

------------------------------------

The maple tree is an RCU-safe range based B-tree designed to use modern
processor cache efficiently. There are a number of places in the kernel
that a non-overlapping range-based tree would be beneficial, especially
one with a simple interface. The first user that is covered in this
patch set is the vm_area_struct, where three data structures are
replaced by the maple tree: the augmented rbtree, the vma cache, and the
linked list of VMAs in the mm_struct. The long term goal is to reduce
or remove the mmap_sem contention.

The tree has a branching factor of 10 for non-leaf nodes and 16 for leaf
nodes. With the increased branching factor, it is significantly shorter than
the rbtree so it has fewer cache misses. The removal of the linked list
between subsequent entries also reduces the cache misses and the need to pull
in the previous and next VMA during many tree alterations.

This patch set is based on v5.18-rc2

git: https://github.com/oracle/linux-uek/tree/howlett/maple/20220426

v8 changes:
- Added preallocations before any potential edits to the tree when holding the
i_mmap_lock to avoid fs-reclaim issues on extreme memory pressure.
- Fixed issue in mempolicy mas_for_each() loop.
- Moved static definitions inside ifdef for DEBUG_MAPLE
- Fixed compile warnings reported by build bots
- Moved mas_dfs_preorder() to testing code
- Changed __vma_adjust() to record the highest vma in case 6 instead of
finding it twice.
- Fixed locking issue in exit_mmap()
- Fixed up from/s-o-b ordering

v7: https://lore.kernel.org/linux-mm/20220404143501.2016403-8-Liam.Howlett@xxxxxxxxxx/
v6: https://lore.kernel.org/linux-mm/20220215143728.3810954-1-Liam.Howlett@xxxxxxxxxx/
v5: https://lore.kernel.org/linux-mm/20220202024137.2516438-1-Liam.Howlett@xxxxxxxxxx/
v4: https://lore.kernel.org/linux-mm/20211201142918.921493-1-Liam.Howlett@xxxxxxxxxx/
v3: https://lore.kernel.org/linux-mm/20211005012959.1110504-1-Liam.Howlett@xxxxxxxxxx/
v2: https://lore.kernel.org/linux-mm/20210817154651.1570984-1-Liam.Howlett@xxxxxxxxxx/
v1: https://lore.kernel.org/linux-mm/20210428153542.2814175-1-Liam.Howlett@xxxxxxxxxx/


Liam R. Howlett (45):
radix tree test suite: add pr_err define
radix tree test suite: add kmem_cache_set_non_kernel()
radix tree test suite: add allocation counts and size to kmem_cache
radix tree test suite: add support for slab bulk APIs
radix tree test suite: add lockdep_is_held to header
mips: rename mt_init to mips_mt_init
Maple Tree: add new data structure
lib/test_maple_tree: add testing for maple tree
mm: start tracking VMAs with maple tree
mm/mmap: use the maple tree in find_vma() instead of the rbtree.
mm/mmap: use the maple tree for find_vma_prev() instead of the rbtree
mm/mmap: use maple tree for unmapped_area{_topdown}
kernel/fork: use maple tree for dup_mmap() during forking
damon: Convert __damon_va_three_regions to use the VMA iterator
mm: remove rb tree.
mmap: change zeroing of maple tree in __vma_adjust()
xen: use vma_lookup() in privcmd_ioctl_mmap()
mm: optimize find_exact_vma() to use vma_lookup()
mm/khugepaged: optimize collapse_pte_mapped_thp() by using
vma_lookup()
mm/mmap: change do_brk_flags() to expand existing VMA and add
do_brk_munmap()
mm: use maple tree operations for find_vma_intersection()
mm/mmap: use advanced maple tree API for mmap_region()
mm: remove vmacache
mm: convert vma_lookup() to use mtree_load()
mm/mmap: move mmap_region() below do_munmap()
mm/mmap: reorganize munmap to use maple states
mm/mmap: change do_brk_munmap() to use do_mas_align_munmap()
arm64: Change elfcore for_each_mte_vma() to use VMA iterator
fs/proc/base: use maple tree iterators in place of linked list
userfaultfd: use maple tree iterator to iterate VMAs
ipc/shm: use VMA iterator instead of linked list
bpf: remove VMA linked list
mm/gup: use maple tree navigation instead of linked list
mm/madvise: use vma_find() instead of vma linked list
mm/memcontrol: stop using mm->highest_vm_end
mm/mempolicy: use vma iterator & maple state instead of vma linked
list
mm/mprotect: use maple tree navigation instead of vma linked list
mm/mremap: use vma_find_intersection() instead of vma linked list
mm/msync: use vma_find() instead of vma linked list
mm/oom_kill: use maple tree iterators instead of vma linked list
mm/swapfile: use vma iterator instead of vma linked list
riscv: use vma iterator for vdso
mm: remove the vma linked list
mm/mmap: drop range_has_overlap() function
mm/mmap.c: pass in mapping to __vma_link_file()

Matthew Wilcox (Oracle) (25):
mm: add VMA iterator
mmap: use the VMA iterator in count_vma_pages_range()
proc: remove VMA rbtree use from nommu
arm64: remove mmap linked list from vdso
parisc: remove mmap linked list from cache handling
powerpc: remove mmap linked list walks
s390: remove vma linked list walks
x86: remove vma linked list walks
xtensa: remove vma linked list walks
cxl: remove vma linked list walk
optee: remove vma linked list walk
um: remove vma linked list walk
coredump: remove vma linked list walk
exec: use VMA iterator instead of linked list
fs/proc/task_mmu: stop using linked list and highest_vm_end
acct: use VMA iterator instead of linked list
perf: use VMA iterator
sched: use maple tree iterator to walk VMAs
fork: use VMA iterator
mm/khugepaged: stop using vma linked list
mm/ksm: use vma iterators instead of vma linked list
mm/mlock: use vma iterator and instead of vma linked list
mm/pagewalk: use vma_find() instead of vma linked list
i915: use the VMA iterator
nommu: remove uses of VMA linked list

Documentation/core-api/index.rst | 1 +
Documentation/core-api/maple_tree.rst | 218 +
MAINTAINERS | 12 +
arch/arm64/kernel/elfcore.c | 16 +-
arch/arm64/kernel/vdso.c | 3 +-
arch/mips/kernel/mips-mt.c | 4 +-
arch/parisc/kernel/cache.c | 7 +-
arch/powerpc/kernel/vdso.c | 6 +-
arch/powerpc/mm/book3s32/tlb.c | 11 +-
arch/powerpc/mm/book3s64/subpage_prot.c | 13 +-
arch/riscv/kernel/vdso.c | 3 +-
arch/s390/kernel/vdso.c | 3 +-
arch/s390/mm/gmap.c | 6 +-
arch/um/kernel/tlb.c | 14 +-
arch/x86/entry/vdso/vma.c | 9 +-
arch/x86/kernel/tboot.c | 2 +-
arch/xtensa/kernel/syscall.c | 18 +-
drivers/firmware/efi/efi.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 14 +-
drivers/misc/cxl/fault.c | 45 +-
drivers/tee/optee/call.c | 18 +-
drivers/xen/privcmd.c | 2 +-
fs/coredump.c | 34 +-
fs/exec.c | 12 +-
fs/proc/base.c | 5 +-
fs/proc/internal.h | 2 +-
fs/proc/task_mmu.c | 74 +-
fs/proc/task_nommu.c | 45 +-
fs/userfaultfd.c | 49 +-
include/linux/maple_tree.h | 685 +
include/linux/mm.h | 74 +-
include/linux/mm_types.h | 43 +-
include/linux/mm_types_task.h | 12 -
include/linux/sched.h | 1 -
include/linux/userfaultfd_k.h | 7 +-
include/linux/vm_event_item.h | 4 -
include/linux/vmacache.h | 28 -
include/linux/vmstat.h | 6 -
include/trace/events/maple_tree.h | 123 +
include/trace/events/mmap.h | 71 +
init/main.c | 2 +
ipc/shm.c | 21 +-
kernel/acct.c | 11 +-
kernel/bpf/task_iter.c | 10 +-
kernel/debug/debug_core.c | 12 -
kernel/events/core.c | 3 +-
kernel/events/uprobes.c | 9 +-
kernel/fork.c | 58 +-
kernel/sched/fair.c | 10 +-
lib/Kconfig.debug | 17 +-
lib/Makefile | 3 +-
lib/maple_tree.c | 6964 +++
lib/test_maple_tree.c | 37854 ++++++++++++++++
mm/Makefile | 2 +-
mm/damon/vaddr-test.h | 37 +-
mm/damon/vaddr.c | 53 +-
mm/debug.c | 14 +-
mm/gup.c | 7 +-
mm/huge_memory.c | 4 +-
mm/init-mm.c | 4 +-
mm/internal.h | 42 +-
mm/khugepaged.c | 13 +-
mm/ksm.c | 18 +-
mm/madvise.c | 2 +-
mm/memcontrol.c | 6 +-
mm/memory.c | 33 +-
mm/mempolicy.c | 56 +-
mm/mlock.c | 34 +-
mm/mmap.c | 2079 +-
mm/mprotect.c | 7 +-
mm/mremap.c | 22 +-
mm/msync.c | 2 +-
mm/nommu.c | 135 +-
mm/oom_kill.c | 3 +-
mm/pagewalk.c | 2 +-
mm/swapfile.c | 4 +-
mm/util.c | 32 -
mm/vmacache.c | 117 -
mm/vmstat.c | 4 -
tools/include/linux/slab.h | 4 +
tools/testing/radix-tree/.gitignore | 2 +
tools/testing/radix-tree/Makefile | 9 +-
tools/testing/radix-tree/generated/autoconf.h | 1 +
tools/testing/radix-tree/linux.c | 160 +-
tools/testing/radix-tree/linux/kernel.h | 1 +
tools/testing/radix-tree/linux/lockdep.h | 2 +
tools/testing/radix-tree/linux/maple_tree.h | 7 +
tools/testing/radix-tree/maple.c | 59 +
.../radix-tree/trace/events/maple_tree.h | 3 +
89 files changed, 47833 insertions(+), 1823 deletions(-)
create mode 100644 Documentation/core-api/maple_tree.rst
create mode 100644 include/linux/maple_tree.h
delete mode 100644 include/linux/vmacache.h
create mode 100644 include/trace/events/maple_tree.h
create mode 100644 lib/maple_tree.c
create mode 100644 lib/test_maple_tree.c
delete mode 100644 mm/vmacache.c
create mode 100644 tools/testing/radix-tree/linux/maple_tree.h
create mode 100644 tools/testing/radix-tree/maple.c
create mode 100644 tools/testing/radix-tree/trace/events/maple_tree.h

--
2.35.1