cpuset_updat...sks_nodemask(9)

🌸 NAME 🌸

cpuset_update_tasks_nodemask — bestie, this is the one that goes through every task in a cpuset and updates their nodemasks for you 💅

(it lives in the Kernel API Manual, iykyk ✨)

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✨ SYNOPSIS ✨

void cpuset_update_tasks_nodemask (struct cpuset *cs );

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🎀 ARGUMENTS 🎀

• cs — the cpuset whose tasks all need their mems_allowed mask changed. that's the whole assignment, no cap 🫶

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🦋 DESCRIPTION 🦋

okay so picture this: it iterates through each and every task of cs, updating its mems_allowed to the effective cpuset's. literally one by one, no skipping, she's thorough 💖

the important part — and hear me out — this function gets called with cpuset_mutex held, so cpuset membership stays stable the entire time. nothing's shifting around under her feet. iconic behavior, honestly 🔥

here's the little crew she's rolling with:

• cpuset_change_task_nodemask: guarantee_online_mems
• mpol_rebind_mm: effective_mems
• cpuset_migrate_mm: guarantee_online_mems
• old_mems_allowed: guarantee_online_mems

and for v2 specifically: guarantee_online_mems should return a node mask that is the same as the effective_mems of current cpuset. that's the vibe check for v2, don't forget it ⭐

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💜 SEE ALSO 💜

Kernel file ./kernel/cgroup/cpuset.c — and the whole friend group, aka:

cpuset_lock(9), cpuset_full_lock(9), partition_is_populated(9), alloc_cpumasks(9), alloc_tmpmasks(9), free_tmpmasks(9), dup_or_alloc_cpuset(9), free_cpuset(9), cpus_excl_conflict(9), cpuset_update_tasks_cpumask(9), compute_effective_cpumask(9), compute_effective_nodemask(9), rm_siblings_excl_cpus(9), update_parent_effective_cpumask(9), compute_partition_effective_cpumask(9), update_sibling_cpumasks(9), validate_partition(9), partition_cpus_change(9), update_cpumask(9), update_exclusive_cpumask(9), update_prstate(9), cpuset_css_alloc(9), cpuset_init(9), cpuset_hotplug_update_tasks(9), cpuset_handle_hotplug(9), cpuset_init_smp(9), cpuset_cpus_allowed_locked(9), cpuset_cpus_allowed(9), cpuset_cpus_allowed_fallback(9), cpuset_mems_allowed(9), cpuset_nodemask_valid_mems_allowed(9), cpuset_nodes_allowed(9), cpuset_spread_node(9), cpuset_mem_spread_node(9), cpuset_mems_allowed_intersects(9), cpuset_print_current_mems_allowed(9)

go read them too, they're all eating, fr fr 👑

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🧚 that's the whole page bestie. ./kernel/cgroup, October 2026 — mwah, take care of her 💅💖🌸