On Fri, Jun 28, 2024 at 03:35:21PM GMT, Lorenzo Stoakes wrote: > There are a number of "core" VMA manipulation functions implemented in > mm/mmap.c, notably those concerning VMA merging, splitting, modifying, > expanding and shrinking, which logically don't belong there. > > More importantly this functionality represents an internal implementation > detail of memory management and should not be exposed outside of mm/ > itself. > > This patch series isolates core VMA manipulation functionality into its own > file, mm/vma.c, and provides an API to the rest of the mm code in mm/vma.h. > > Importantly, it also carefully implements mm/vma_internal.h, which > specifies which headers need to be imported by vma.c, leading to the very > useful property that vma.c depends only on mm/vma.h and mm/vma_internal.h. > > This is useful, because we can then re-implement vma_internal.h in > userland, stubbing out and adding shims for kernel mechanisms as required, > and then can directly and very easily unit test internal VMA functionality. > > This patch series takes advantage of existing shim logic and full userland > maple tree support contained in tools/testing/radix-tree/ and > tools/include/linux/, separating out shared components of the radix tree > implementation to provide this testing. > > Kernel functionality is stubbed and shimmed as needed in tools/testing/vma/ > which contains a fully functional userland vma_internal.h file and which > imports mm/vma.c and mm/vma.h to be directly tested from userland. > > A simple, skeleton testing implementation is provided in > tools/testing/vma/vma.c as a proof-of-concept, asserting that simple VMA > merge, modify (testing split), expand and shrink functionality work > correctly. > > v2: > * Reword commit messages. > * Replace vma_expand() / vma_shrink() wrappers with relocate_vma(). > * Make move_page_tables() internal too. > * Have internal.h import vma.h. > * Use header guards to more cleanly implement userland testing code. > * Rename main.c to vma.c. > * Update mm/vma_internal.h to have fewer superfluous comments. > * Rework testing logic so we count test failures, and output test results. > * Correct some SPDX license prefixes. > * Make VM_xxx_ON() debug asserts forward to xxx_ON() macros. > * Update VMA tests to correctly free memory, and re-enable ASAN leak > detection. > > v1: > https://lore.kernel.org/all/cover.1719481836.git.lstoakes@xxxxxxxxx/ > > Lorenzo Stoakes (7): > userfaultfd: move core VMA manipulation logic to mm/userfaultfd.c > mm: move vma_modify() and helpers to internal header > mm: move vma_shrink(), vma_expand() to internal header > mm: move internal core VMA manipulation functions to own file > MAINTAINERS: Add entry for new VMA files > tools: separate out shared radix-tree components > tools: add skeleton code for userland testing of VMA logic > As this is stabilising and there seems to be no major objections, the next re-spin will be sent un-RFC'd. I have a few small fixes on the userland testing code I will include, in addition to the stuff commented on here. > MAINTAINERS | 14 + > fs/exec.c | 68 +- > fs/userfaultfd.c | 160 +- > include/linux/atomic.h | 2 +- > include/linux/mm.h | 112 +- > include/linux/mmzone.h | 3 +- > include/linux/userfaultfd_k.h | 19 + > mm/Makefile | 2 +- > mm/internal.h | 167 +- > mm/mmap.c | 2070 ++--------------- > mm/mmu_notifier.c | 2 + > mm/userfaultfd.c | 168 ++ > mm/vma.c | 1766 ++++++++++++++ > mm/vma.h | 362 +++ > mm/vma_internal.h | 52 + > tools/testing/radix-tree/Makefile | 68 +- > tools/testing/radix-tree/maple.c | 14 +- > tools/testing/radix-tree/xarray.c | 9 +- > tools/testing/shared/autoconf.h | 2 + > tools/testing/{radix-tree => shared}/bitmap.c | 0 > tools/testing/{radix-tree => shared}/linux.c | 0 > .../{radix-tree => shared}/linux/bug.h | 0 > .../{radix-tree => shared}/linux/cpu.h | 0 > .../{radix-tree => shared}/linux/idr.h | 0 > .../{radix-tree => shared}/linux/init.h | 0 > .../{radix-tree => shared}/linux/kconfig.h | 0 > .../{radix-tree => shared}/linux/kernel.h | 0 > .../{radix-tree => shared}/linux/kmemleak.h | 0 > .../{radix-tree => shared}/linux/local_lock.h | 0 > .../{radix-tree => shared}/linux/lockdep.h | 0 > .../{radix-tree => shared}/linux/maple_tree.h | 0 > .../{radix-tree => shared}/linux/percpu.h | 0 > .../{radix-tree => shared}/linux/preempt.h | 0 > .../{radix-tree => shared}/linux/radix-tree.h | 0 > .../{radix-tree => shared}/linux/rcupdate.h | 0 > .../{radix-tree => shared}/linux/xarray.h | 0 > tools/testing/shared/maple-shared.h | 9 + > tools/testing/shared/maple-shim.c | 7 + > tools/testing/shared/shared.h | 34 + > tools/testing/shared/shared.mk | 68 + > .../testing/shared/trace/events/maple_tree.h | 5 + > tools/testing/shared/xarray-shared.c | 5 + > tools/testing/shared/xarray-shared.h | 4 + > tools/testing/vma/.gitignore | 6 + > tools/testing/vma/Makefile | 15 + > tools/testing/vma/errors.txt | 0 > tools/testing/vma/generated/autoconf.h | 2 + > tools/testing/vma/linux/atomic.h | 12 + > tools/testing/vma/linux/mmzone.h | 38 + > tools/testing/vma/vma.c | 207 ++ > tools/testing/vma/vma_internal.h | 882 +++++++ > 51 files changed, 3910 insertions(+), 2444 deletions(-) > create mode 100644 mm/vma.c > create mode 100644 mm/vma.h > create mode 100644 mm/vma_internal.h > create mode 100644 tools/testing/shared/autoconf.h > rename tools/testing/{radix-tree => shared}/bitmap.c (100%) > rename tools/testing/{radix-tree => shared}/linux.c (100%) > rename tools/testing/{radix-tree => shared}/linux/bug.h (100%) > rename tools/testing/{radix-tree => shared}/linux/cpu.h (100%) > rename tools/testing/{radix-tree => shared}/linux/idr.h (100%) > rename tools/testing/{radix-tree => shared}/linux/init.h (100%) > rename tools/testing/{radix-tree => shared}/linux/kconfig.h (100%) > rename tools/testing/{radix-tree => shared}/linux/kernel.h (100%) > rename tools/testing/{radix-tree => shared}/linux/kmemleak.h (100%) > rename tools/testing/{radix-tree => shared}/linux/local_lock.h (100%) > rename tools/testing/{radix-tree => shared}/linux/lockdep.h (100%) > rename tools/testing/{radix-tree => shared}/linux/maple_tree.h (100%) > rename tools/testing/{radix-tree => shared}/linux/percpu.h (100%) > rename tools/testing/{radix-tree => shared}/linux/preempt.h (100%) > rename tools/testing/{radix-tree => shared}/linux/radix-tree.h (100%) > rename tools/testing/{radix-tree => shared}/linux/rcupdate.h (100%) > rename tools/testing/{radix-tree => shared}/linux/xarray.h (100%) > create mode 100644 tools/testing/shared/maple-shared.h > create mode 100644 tools/testing/shared/maple-shim.c > create mode 100644 tools/testing/shared/shared.h > create mode 100644 tools/testing/shared/shared.mk > create mode 100644 tools/testing/shared/trace/events/maple_tree.h > create mode 100644 tools/testing/shared/xarray-shared.c > create mode 100644 tools/testing/shared/xarray-shared.h > create mode 100644 tools/testing/vma/.gitignore > create mode 100644 tools/testing/vma/Makefile > create mode 100644 tools/testing/vma/errors.txt > create mode 100644 tools/testing/vma/generated/autoconf.h > create mode 100644 tools/testing/vma/linux/atomic.h > create mode 100644 tools/testing/vma/linux/mmzone.h > create mode 100644 tools/testing/vma/vma.c > create mode 100644 tools/testing/vma/vma_internal.h > > -- > 2.45.1
