[kvm-unit-tests,v2,00/11] Fix and improve the page allocator

Message

Claudio Imbrenda Jan. 15, 2021, 12:37 p.m. UTC

My previous patchseries was rushed and not polished enough. Furthermore it
introduced some regressions.

This patchseries fixes hopefully all the issues reported, and introduces
some new features.

It also simplifies the code and hopefully makes it more readable.

Fixed:
* allocated memory is now zeroed by default

New features:
* per-allocation flags to specify not just the area (like before) but also
  other parameters
  - dontzero flag: the allocation will not be zeroed
  - fresh flag: the returned memory has never been read or written to before

I would appreciate if people could test these patches, especially on
strange, unusual or exotic hardware (I tested only on s390x)


GitLab:
  https://gitlab.com/imbrenda/kvm-unit-tests/-/tree/page_allocator_fixes
CI:
  https://gitlab.com/imbrenda/kvm-unit-tests/-/pipelines/241819726


v1->v2
* have DONTZERO flag instead of a ZERO flag, this way there is no need
  for a default.
* drop the last patch, since there is no need for a default now.
* fixed a pre-existing bug that caused wrong allocations
* renamed alloc_pages_special to reserve_pages, to make it clear it is
  not a normal allocation. The function now returns 0 on success and -1
  on failure.
* added a NULL check in vm_free; freeing a NULL pointer is now a no-op.
* fix and improve some comments
* remove a spurious return 

Claudio Imbrenda (11):
  lib/x86: fix page.h to include the generic header
  lib/list.h: add list_add_tail
  lib/vmalloc: add some asserts and improvements
  lib/asm: Fix definitions of memory areas
  lib/alloc_page: fix and improve the page allocator
  lib/alloc.h: remove align_min from struct alloc_ops
  lib/alloc_page: Optimization to skip known empty freelists
  lib/alloc_page: rework metadata format
  lib/alloc: replace areas with more generic flags
  lib/alloc_page: Wire up FLAG_DONTZERO
  lib/alloc_page: Properly handle requests for fresh blocks

 lib/asm-generic/memory_areas.h |   9 +-
 lib/arm/asm/memory_areas.h     |  11 +-
 lib/arm64/asm/memory_areas.h   |  11 +-
 lib/powerpc/asm/memory_areas.h |  11 +-
 lib/ppc64/asm/memory_areas.h   |  11 +-
 lib/s390x/asm/memory_areas.h   |  13 +-
 lib/x86/asm/memory_areas.h     |  27 ++--
 lib/x86/asm/page.h             |   4 +-
 lib/alloc.h                    |   1 -
 lib/alloc_page.h               |  76 ++++++---
 lib/list.h                     |   9 ++
 lib/alloc_page.c               | 283 +++++++++++++++++++--------------
 lib/alloc_phys.c               |   9 +-
 lib/s390x/smp.c                |   2 +-
 lib/vmalloc.c                  |  23 +--
 15 files changed, 284 insertions(+), 216 deletions(-)