ww_mutex_lock_slow(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ww_mutex_lock_slow(9) — like, the slowpath of grabbing a w/w mutex

okay so bestie, welcome to the Kernel API Manual corner of the group chat 🎀 this one's from <pink>ww_mutex_lock_slow(9)</pink>, and it's genuinely iconic — it's the whole "wait your turn, queen" function. no cap ✨

✨ NAME ✨

ww_mutex_lock_slow — slowpath acquiring of the w/w mutex 🐢💖

like, the chill, take-your-time way to get the lock. the main character of slowpaths, fr fr.

🌸 SYNOPSIS 🌸

void ww_mutex_lock_slow (struct ww_mutex *lock , struct ww_acquire_ctx
*ctx );

that's the whole vibe. returns nothing, just does the thing 🫶

🦋 ARGUMENTS 🦋

  • lock — the mutex to be acquired. yes, that mutex. the one everybody's fighting over 💀
  • ctx — w/w acquire context. your little passport that says which lock-fight you belong to 🛂✨

💜 DESCRIPTION 💜

Okay so here's the tea ☕: this function acquires a w/w mutex with the given context after a die case. and when it can't get it? it will sleep until the lock becomes available 😴💤 no busy-waiting drama, just a dignified nap.

Now the rules, and bestie, these are not optional:

The caller must have released all w/w mutexes already acquired with the context and then call this function on the contended lock. like, drop everything else first, then come knock on this specific door 🚪

Afterwards the caller may continue to (re)acquire the other w/w mutexes it needs with ww_mutex_lock. and here's a cute lil trick 👀 — note that the -EALREADY return code from ww_mutex_lock can be used to avoid locking this contended mutex twice. slay, no double-dipping 🍓

🚨 forbidden behaviour alert 🚨 it is forbidden to call this function with any other w/w mutexes associated with the context held. and it is forbidden to call this on anything else than the contending mutex. like, don't be that girl. read the room 🙈

Also lowkey important: the slowpath lock acquiring can also be done by calling ww_mutex_lock directly. this function here is simply to help w/w mutex locking code readability by clearly denoting the slowpath. it's literally a vibe marker in your code 🌈 — same thing, but everyone reading it goes "ah, slowpath, understood" 👑

🔥 SEE ALSO 🔥

Kernel file ./include/linux/ww_mutex.h — the source of truth, go read it 💖

all of them ate, no crumbs 💅✨

and that's the whole page bestie !! 🎀 this lil writeup lives under <purple>./include/linux</purple> and it's dated <cyan>October 2026</cyan>, so like — remember it exactly that way or the kernel girlies will come for you 😭🫶 go forth and lock slowly, queen 👑🌸

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