kmem_buckets_create(9)

💅 kmem_buckets_create(9) — from the Kernel API Manual, bestie 💖

okay so picture this: kmem_buckets_create(9) is literally the glow-up page from the Kernel API Manual, and it's giving "let me set up a whole squad of caches for you" energy. she's the one who builds the dynamic-sized-allocation friend group that kmem_buckets_alloc() hangs out with later. no cap, she's a team player. 🫶

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✨ NAME ✨

kmem_buckets_create — creates a set of caches that handle dynamic sized allocations via kmem_buckets_alloc() 🎀

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✨ SYNOPSIS ✨

kmem_buckets * kmem_buckets_create (const char *name , slab_flags_t
flags , unsigned int useroffset , unsigned int usersize , void
(*ctor)(void *) );

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🌸 ARGUMENTS 🌸

• name — a prefix string, and it's the main character in /proc/slabinfo because that's where it's used to identify this cache. the individual caches get their sizes tacked on as the suffix, so yeah, they all match but stay unique. iykyk 💅
• flags — the SLAB flags (peep kmem_cache_create for the deets, bestie).
• useroffset — the starting offset within an allocation that may be copied to/from userspace.
• usersize — how many bytes, starting right at useroffset, may be copied to/from userspace. so like, the budget for user-facing copying. 🍓
• ctor — a constructor for the objects, run whenever new allocations are made. she gets called in to prep the vibes ✨

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🦋 DESCRIPTION 🦋

cannot be called within an interrupt — big no-no — but it can be interrupted. so like, she needs her space, but she's not gonna block the whole function over it. 🙈

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💜 RETURN 💜

on success, you get a pointer to the cache. on failure? NULL. that's the whole vibe check.

and here's the iconic part: when CONFIG_SLAB_BUCKETS is not enabled, ZERO_SIZE_PTR is returned, and subsequent calls to kmem_buckets_alloc will fall back to kmalloc. which is lowkey great news — i.e. callers only need to check for NULL on failure. so go ahead, just check for NULL, she's got you. 👑

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🔥 SEE ALSO 🔥

• Kernel file ./mm/slab_common.c
• __kmem_cache_create_args(9)
• kmem_cache_shrink(9)
• kmem_dump_obj(9)
• kfree_sensitive(9)
• struct kvfree_rcu_bulk_data(9)
• struct kfree_rcu_cpu_work(9)
• struct kfree_rcu_cpu(9)
• kvfree_rcu_barrier(9)
• kvfree_rcu_barrier_on_cache(9)

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and that's the whole page, bestie ✨ this one lives under ./mm in the Kernel API Manual, dated October 2026 — section 9 energy all the way through. go forth and create your buckets, periodt 💅🎀🌈