mempool_alloc(9)

💖 mempool_alloc — from the Kernel API Manual, bestie 💖

okay so picture this: you're deep in the kernel, you need a chunk of memory, and you absolutely cannot afford to be let down. that's literally this function. welcome to the group chat 🫶

✨ NAME ✨

mempool_alloc — allocate an element from a memory pool. yes that's it, that's the whole vibe. pulling a lil something out of the box 📦

🌸 SYNOPSIS 🌸

void * mempool_alloc (struct mempool *pool , gfp_t gfp_mask );

like. look at her. two args, zero drama ✨

🎀 ARGUMENTS 🎀

• pool — pointer to the memory pool. this is your box, your stash, your main-character pool that you're grabbing from 💅
• gfp_mask — the GFP_* flags. and listen: __GFP_ZERO is not supported. not "discouraged", not "deprecated", just straight up not supported, so don't come for her 🙈

🦋 DESCRIPTION 🦋

okay so the way this works: you're allocating an element from pool. and it's a two-step slay ✨

1. first, she calls into the alloc_fn that was supplied at pool initialization time 🔥
2. then, when alloc_fn fails to allocate an element, she dips into the reserved pool 🍓

so like, there's a backup plan built in. it's giving prepared. it's giving "i have a snack in my bag just in case".

now the sleep situation, because this is important: this function only sleeps if the alloc_fn callback sleeps, or when it's waiting for elements to become available in the pool. that's it. those are the two times. no random napping 💀

⭐ RETURN ⭐

she returns a pointer to the allocated element 💖 — or NULL when she fails to allocate an element 😭

and here's the tea: allocation failure can only happen when gfp_mask does not include __GFP_DIRECT_RECLAIM. no cap. that's the only failure path. so if you did pass that flag, sit back and relax bestie 🌈

👑 SEE ALSO 👑

the kernel file ./mm/mempool.c, and honestly the whole friend group:

• mempool_exit(9)
• mempool_destroy(9)
• mempool_init(9)
• mempool_create_node(9)
• mempool_resize(9)
• mempool_alloc_bulk(9)
• mempool_alloc_preallocated(9)
• mempool_free_bulk(9)
• mempool_free(9)

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and that's the page!! mwah 💋 this one came straight out of ./mm and it's dated October 2026 — so like, future girlie behavior honestly 🌸✨ go allocate something iconic, ily, bye 🧚💜