[PATCH v2 00/21] remove the SLAB allocator

Vlastimil Babka
2023-11-20T18:34:41Z

Changes from v1:
- Added new Patch 01 to fix up kernel docs build (thanks Marco Elver)
- Additional changes to Kconfig user visible texts in Patch 02 (thanks Kees
Cook)
- Whitespace fixes and other fixups (thanks Kees)

The SLAB allocator has been deprecated since 6.5 and nobody has objected
so far. As we agreed at LSF/MM, we should wait with the removal until
the next LTS kernel is released. This is now determined to be 6.6, and
we just missed 6.7, so now we can aim for 6.8 and start exposing the
removal to linux-next during the 6.7 cycle. If nothing substantial pops
up, will start including this in slab-next later this week.

To keep the series reasonably sized and not pull in people from other
subsystems than mm and closely related ones, I didn't attempt to remove
every trace of unnecessary reference to dead config options in external
areas, nor in the defconfigs. Such cleanups can be sent to and handled
by respective maintainers after this is merged.

Instead I have added some patches aimed to reap some immediate benefits
of the removal, mainly by not having to split some fastpath code between
slab_common.c and slub.c anymore. But that is also not an exhaustive
effort and I expect more cleanups and optimizations will follow later.

Patch 09 updates CREDITS for the removed mm/slab.c. Please point out if
I missed someone not yet credited.

Git version: https://git.kernel.org/vbabka/l/slab-remove-slab-v2r1

---
Vlastimil Babka (21):
mm/slab, docs: switch mm-api docs generation from slab.c to slub.c
mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile
KASAN: remove code paths guarded by CONFIG_SLAB
KFENCE: cleanup kfence_guarded_alloc() after CONFIG_SLAB removal
mm/memcontrol: remove CONFIG_SLAB #ifdef guards
cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
mm/slab: remove CONFIG_SLAB code from slab common code
mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs
mm/slab: remove mm/slab.c and slab_def.h
mm/slab: move struct kmem_cache_cpu declaration to slub.c
mm/slab: move the rest of slub_def.h to mm/slab.h
mm/slab: consolidate includes in the internal mm/slab.h
mm/slab: move pre/post-alloc hooks from slab.h to slub.c
mm/slab: move memcg related functions from slab.h to slub.c
mm/slab: move struct kmem_cache_node from slab.h to slub.c
mm/slab: move kfree() from slab_common.c to slub.c
mm/slab: move kmalloc_slab() to mm/slab.h
mm/slab: move kmalloc() functions from slab_common.c to slub.c
mm/slub: remove slab_alloc() and __kmem_cache_alloc_lru() wrappers
mm/slub: optimize alloc fastpath code layout
mm/slub: optimize free fast path code layout

CREDITS | 12 +-
Documentation/core-api/mm-api.rst | 2 +-
arch/arm64/Kconfig | 2 +-
arch/s390/Kconfig | 2 +-
arch/x86/Kconfig | 2 +-
include/linux/cpuhotplug.h | 1 -
include/linux/slab.h | 22 +-
include/linux/slab_def.h | 124 --
include/linux/slub_def.h | 204 --
kernel/cpu.c | 5 -
lib/Kconfig.debug | 1 -
lib/Kconfig.kasan | 11 +-
lib/Kconfig.kfence | 2 +-
lib/Kconfig.kmsan | 2 +-
mm/Kconfig | 68 +-
mm/Kconfig.debug | 16 +-
mm/Makefile | 6 +-
mm/dmapool.c | 2 +-
mm/kasan/common.c | 13 +-
mm/kasan/kasan.h | 3 +-
mm/kasan/quarantine.c | 7 -
mm/kasan/report.c | 1 +
mm/kfence/core.c | 4 -
mm/memcontrol.c | 6 +-
mm/mempool.c | 6 +-
mm/slab.c | 4026 -------------------------------------
mm/slab.h | 551 ++---
mm/slab_common.c | 231 +--
mm/slub.c | 617 +++++-
29 files changed, 815 insertions(+), 5134 deletions(-)
---
base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
change-id: 20231120-slab-remove-slab-a76ec668d8c6

Best regards,
--
Vlastimil Babka <vbabka@suse.cz>