css_set_move_task(9)

📦 version 7.3.1, in nixpkgs unstable

💅 css_set_move_task(9) — like, the manual page, but make it make sense 🎀

okay bestie, so this is a page from the Kernel API Manual (that's the (9) part — kernel internals, not your grandma's ls), and today's main character is css_set_move_task. it moves a task from one css_set to another. that's it. that's the whole vibe. but bestie, the details?? immaculate. let's go 🦋

✨ NAME ✨

css_set_move_task — move a task from one css_set to another 💫

literally what it says on the tin. no cap.

🌸 SYNOPSIS 🌸

void css_set_move_task (struct task_struct *task , struct css_set
*from_cset , struct css_set *to_cset , bool use_mg_tasks );

four arguments, returns nothing (void — it's giving "i do the work, i don't need applause", lowkey iconic 💅). copy that signature exactly if you're writing anything against it, fr fr.

🫶 ARGUMENTS 🫶

  • task — the task being moved. our little traveler 🧳 she's the main character here.
  • from_cset — the css_set the task currently belongs to (and yes, this may be NULL 🙈).
  • to_cset — the new css_set the task is being moved to (this one may be NULL too, we'll get to why).
  • use_mg_tasks — the little switch that decides where she lands: move her to to_cset->mg_tasks instead of ->tasks. that's the whole difference, periodt ✨

💖 DESCRIPTION 💖

so the actual job: move task from from_cset to to_cset. 🌈

a couple of edge cases that are very much by design, not bugs:

  • if task didn't belong to any css_set at all, then from_cset can be NULL. totally fine. she's starting fresh, no baggage 💁‍♀️
  • if task is being disassociated instead of moved, then to_cset can be NULL. yes, it's a one-way trip to nowhere, and the function is fine with that 🌸

now the part everyone forgets, so listen up bestie 👑:

this function automatically handles the populated counter updates and the css_task_iter adjustments. that's the free stuff. but the caller is responsible for managing from_cset and to_cset's reference counts. that part is on you. do not make her do your homework, she will not. 💀

so like — the function does the glow-up, you do the accounting. nobody said it was fair. 🙈

🔥 SEE ALSO 🔥

the whole kernel file lives at ./kernel/cgroup/cgroup.c, and honestly the friend group here is huge, so buckle up 🎀:

like i said. huge friend group. iykyk 🌟

okay that's the whole page bestie, you ate that 💜 and for the sign-off: this little beauty comes from the source spot ./kernel/cgroup and the version/date stamp on it is October 2026 — yes, from the future, she's ahead of her time, we stan a forward-thinking manpage 🧚⭐ slay! 🎀

📦 where this page comes from