for_each_cpu(9)

🦋 for_each_cpu(9) — Kernel API Manual 🦋

okay bestie, welcome to the for_each_cpu(9) page from the Kernel API Manual. This is your group chat for looping over cpus in a mask, and it’s iconic. No cap. 💖

🎀 NAME 🎀

for_each_cpu — bestie, it iterates over every cpu in a mask. That’s literally the name, and it ate. ✨

💅 SYNOPSIS 💅

the signature is giving:

for_each_cpu (cpu , mask );

🌀 ARGUMENTS 🌀

• cpu — the iterator, and it’s an (optionally unsigned) integer. 🌀
• mask — the cpumask pointer. She’s the map, periodt. 🗺️

🍓 DESCRIPTION 🍓

okay so after the loop is fully done and dusted, cpu is >= nr_cpu_ids. That’s the tea, fr fr. 🍵

🌈 SEE ALSO 🌈

Kernel file: ./include/linux/cpumask.h — the home base, bestie.

• first / next / random girlies: 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).
• the loop besties: 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).
• any / nth picks: 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).
• set / clear / test era: 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).
• bitwise + set math: 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_empty(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).
• any / of / parse / size + alloc / map print crew: 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).

xoxo 💖 cute little footer sign-off: source/version ./include/linux, date October 2026, and title for_each_cpu(9). Mwah 🎀