[v6,0/8] xen/spinlock: make recursive spinlocks a dedicated type

Message

Jürgen Groß March 27, 2024, 3:22 p.m. UTC

Instead of being able to use normal spinlocks as recursive ones, too,
make recursive spinlocks a special lock type.

This will make the spinlock structure smaller in production builds and
add type-safety.

This allows to increase the maximum number of physical cpus from 4095
to 65535 without increasing the size of the lock structure in production
builds (the size of recursive spinlocks in debug builds will grow to
12 bytes due to that change).

Note that rwlock handling is still limiting the number of cpus to 4095,
this is being taken care off in patch 12, which raises the rwlock limit
to 16384 cpus.

Iommu code imposes a limit of 16383 cpus.

Changes in V2:
- addressed comments by Jan Beulich
- lots of additional cleanups
- reorganized complete series

Changes in V3:
- addressed comments by Jan Beulich

Changes in V4:
- former patch 1 has already been applied
- fixed a coding style issue in patch 1

Changes in V5:
- new patches 1 + 10 + 12 + 13
- due to the recent Ghost-race patches the macro layer for calling
  spinlock functions is kept
- addressed comments

Changes in V6:
- patches 1-5 of V5 have been committed already
- addressed comments

Juergen Gross (8):
  xen/spinlock: add explicit non-recursive locking functions
  xen/spinlock: add another function level
  xen/spinlock: add missing rspin_is_locked() and rspin_barrier()
  xen/spinlock: split recursive spinlocks from normal ones
  xen/spinlock: let all is_locked and trylock variants return bool
  xen/spinlock: support higher number of cpus
  xen/rwlock: raise the number of possible cpus
  xen: allow up to 16383 cpus

 xen/arch/Kconfig              |   2 +-
 xen/arch/arm/mm.c             |   4 +-
 xen/arch/x86/domain.c         |  12 +--
 xen/arch/x86/mm.c             |  12 +--
 xen/arch/x86/mm/mem_sharing.c |   8 +-
 xen/arch/x86/mm/p2m-pod.c     |   6 +-
 xen/arch/x86/mm/p2m.c         |   4 +-
 xen/arch/x86/tboot.c          |   4 +-
 xen/common/domain.c           |   2 +-
 xen/common/domctl.c           |   4 +-
 xen/common/grant_table.c      |  10 +-
 xen/common/memory.c           |   4 +-
 xen/common/numa.c             |   4 +-
 xen/common/page_alloc.c       |  18 ++--
 xen/common/spinlock.c         | 181 ++++++++++++++++++++++++++--------
 xen/drivers/char/console.c    |  20 ++--
 xen/drivers/passthrough/pci.c |   2 +-
 xen/include/xen/rwlock.h      |  23 +++--
 xen/include/xen/spinlock.h    | 110 ++++++++++++++++-----
 19 files changed, 297 insertions(+), 133 deletions(-)