cpumask_empty(9)

💖 cpumask_empty 💖 (section 9, from the Kernel API Manual, bestie)

Okay so listen — this one is short and it slays. Literally the whole job is answering one question: is this cpu mask empty or not? That's it. That's the function. No cap. ✨

🌸 NAME 🌸

cpumask_empty — literally just *srcp == 0 🫶

🎀 SYNOPSIS 🎀

bool cpumask_empty (const struct cpumask *srcp );

🦋 ARGUMENTS 🦋

• srcp — the cpumask you're passing in, bestie: the one where all the cpus < nr_cpu_ids are clear. That's the whole vibe check. 💅

⭐ RETURN ⭐

It hands you back true if srcp is empty (aka has no bits set), otherwise it's false. Iconic behaviour, honestly. 💖

🔥 SEE ALSO 🔥

They live in the kernel file ./include/linux/cpumask.h, and the whole friend group is tagged in this post — every single one of them, no skipping, I don't make the rules 👑

• cpumask_pr_args(9), cpumask_first(9), cpumask_first_zero(9), cpumask_first_and(9), cpumask_first_andnot(9), cpumask_first_and_and(9), cpumask_last(9)
• cpumask_next(9), cpumask_next_zero(9), cpumask_next_and(9), cpumask_next_andnot(9), cpumask_next_and_wrap(9), cpumask_next_wrap(9), cpumask_random(9)
• for_each_cpu(9), for_each_cpu_wrap(9), for_each_cpu_and(9), for_each_cpu_andnot(9), for_each_cpu_or(9), for_each_cpu_from(9)
• cpumask_any_but(9), cpumask_any_and_but(9), cpumask_any_andnot_but(9)
• cpumask_nth(9), cpumask_nth_and(9), cpumask_nth_and_andnot(9)
• cpumask_set_cpu(9), cpumask_clear_cpus(9), cpumask_clear_cpu(9), cpumask_test_cpu(9), cpumask_test_and_set_cpu(9), cpumask_test_and_clear_cpu(9), cpumask_setall(9), cpumask_clear(9)
• cpumask_and(9), cpumask_or(9), cpumask_weighted_or(9), cpumask_xor(9), cpumask_andnot(9)
• cpumask_equal(9), cpumask_or_equal(9), cpumask_intersects(9), cpumask_subset(9), cpumask_full(9)
• cpumask_weight(9), cpumask_weight_and(9), cpumask_weight_andnot(9)
• cpumask_shift_right(9), cpumask_shift_left(9), cpumask_copy(9)
• cpumask_any(9), cpumask_any_and(9), cpumask_of(9)
• cpumask_parse_user(9), cpumask_parselist_user(9), cpumask_parse(9), cpulist_parse(9), cpumask_size(9), alloc_cpumask_var(9), to_cpumask(9), num_online_cpus(9), cpumap_print_bitmask_to_buf(9), cpumap_print_list_to_buf(9)

ngl the whole page is one boolean check and I respect the commitment 💀 keep it in your back pocket, iykyk 🙈

Okay that's the whole read, bestie — sourced straight out of ./include/linux, dated October 2026, and yeah, the header still calls it cpumask_empty(9) like a proper Kernel API Manual entry 🎀✨ Byeee 💜