This started by the report that SLAB_MEM_SPREAD flag is dead (Patch 1). Then in the alloc profiling series we realized it's too easy to reuse an existing SLAB_ flag's value when defining a new one, by mistake. Thus let the compiler do that for us via a new helper enum (Patch 2). When checking if more flags are dead or could be removed, didn't spot any, but found out the SLAB_KASAN handling of preventing cache merging can be simplified since we now have an explicit SLAB_NO_MERGE (Patch 3). The SLAB_MEM_SPREAD flag is now marked as unused and for removal, and has a value of 0 so it's a no-op. Patches to remove its usage can/will be submitted to respective subsystems independently of this series - the flag is already dead as of v6.8-rc1 with SLAB removed. The removal of dead cpuset_do_slab_mem_spread() code can also be submitted independently. Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> --- Changes in v2: - Collect R-b, T-b (thanks!) - Unify all disabled flags's value to a sparse-happy zero with a new macro (lkp/sparse). - Rename __SF_BIT to __SLAB_FLAG_BIT (Roman Gushchin) - Rewrod kasan_cache_create() comment (Andrey Konovalov) - Link to v1: https://lore.kernel.org/r/20240220-slab-cleanup-flags-v1-0-e657e373944a@xxxxxxx --- Vlastimil Babka (3): mm, slab: deprecate SLAB_MEM_SPREAD flag mm, slab: use an enum to define SLAB_ cache creation flags mm, slab, kasan: replace kasan_never_merge() with SLAB_NO_MERGE include/linux/kasan.h | 6 ---- include/linux/slab.h | 97 ++++++++++++++++++++++++++++++++++++--------------- mm/kasan/generic.c | 22 ++++-------- mm/slab.h | 1 - mm/slab_common.c | 2 +- mm/slub.c | 6 ++-- 6 files changed, 79 insertions(+), 55 deletions(-) --- base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d change-id: 20240219-slab-cleanup-flags-c864415ecc8e Best regards, -- Vlastimil Babka <vbabka@xxxxxxx>
