On 3/12/22 14:08, Vlastimil Babka wrote: > On 3/12/22 13:06, Mike Rapoport wrote: >>>>> Ideas? implementing something like kmem_cache_init_early() again? >>>> >>>> I think we could simply make CONFIG_SLUB_DEBUG_ON select/depend on >>>> STACKDEPOT_ALWAYS_INIT? >>> >>> Oh, sounds better. >>> >>> If we make CONFIG_SLUB_DEBUG_ON select STACK_DEPOT_ALWAYS_INIT, >>> that is simple solution. but stackdepot will be initialized on >>> slub_debug=- too. > > Valid point. > >>> But I think no one will set CONFIG_SLUB_DEBUG_ON=y if not debugging... >> >> If memory wasted by stack_table is a real concern, we may free it after >> parsing slub_debug or add a condition taking into account >> CONFIG_SLUB_DEBUG_ON and slub_debug=- to the >> >> if (slub_debug & SLAB_STORE_USER) >> stack_depot_want_early_init(); >> >> But I agree that if somebody runs a kernel with CONFIG_SLUB_DEBUG_ON=y, the >> goal is to have slub debugging on, so making CONFIG_SLUB_DEBUG_ON select >> STACK_DEPOT_ALWAYS_INIT totally makes sense to me. > > Agree. We had to decouple stackdpepot init from CONFIG_SLUB_DEBUG > because almost everyone enables CONFIG_SLUB_DEBUG by default, but on > smaller systems doesn't want to always pay the price even if unused. > But I don't expect anyone to enable CONFIG_SLUB_DEBUG_ON and then run > with slub_debug=- by default, and complain. If anyone like that exists, > they could also add the stackdepot_disable parameter. Pushed fixed version to https://git.kernel.org/cgit/linux/kernel/git/vbabka/linux.git slub-stackdepot-v3r1 for now As it's too late to target 5.18 now, will post v3 properly after merge window and add to slab-next towards 5.19 then. >>> I don't think making CONFIG_SLUB_DEBUG_ON depend on >>> CONFIG_STACKDEPOT_ALWAYS_INIT is good solution. only KASAN selects it. >>> >>> -- >>> Thank you, You are awesome! >>> Hyeonggon :-) >> >
