usleep_range_state(9)

💤 usleep_range_state(9) 💤

okay bestie, welcome to the Kernel API Manual ✨ this one's literally called usleep_range_state and it does exactly what it says on the tin — no cap.

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🌸 NAME 🌸

usleep_range_state — sleep for an approximate time in a given state 🎀

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✨ SYNOPSIS ✨

void usleep_range_state (unsigned long min , unsigned long max ,
       unsigned int state );

like... that's the whole vibe. three args, one nap. 🦋

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🫶 ARGUMENTS 🫶

• min — the minimum time in usecs to sleep. the floor, the bare minimum, the "at least this long" of it all 💅
• max — the maximum time in usecs to sleep. the ceiling, the upper limit, the "not a usec longer" 🎀
• state — the state of the current task while it's sleeping. yes, that state. it will be while sleeping. iconique 💜

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🔥 DESCRIPTION 🔥

okay so picture this: usleep_range_state sleeps at least for the minimum time you specified, but not longer than the maximum amount of time you specified. so far so straightforward, right? 💅

but here's the slay part — that range might lowkey reduce power usage by letting hrtimers coalesce an already scheduled interrupt with this hrtimer. the way that works?? literally saving watts. ⚡ and in the worst case, an interrupt is scheduled for the upper bound. worst case is still fine, bestie. we love a graceful fallback. 🫶

the sleeping task is set to the specified state before starting the sleep. like getting into bed before you doomscroll. 🛏️✨

now, listen — in non-atomic context where the exact wakeup time is flexible, use usleep_range or its variants instead of udelay. and why? because the sleep improves responsiveness by avoiding the CPU-hogging busy-wait of udelay. udelay is out here spinning and hogging the CPU like that one friend who won't let anyone else talk 😭 not the move. usleep_range is giving main character energy and it's polite to your processor. 🌈

⭐ tiny vibe check: min and max are in usecs — microseconds, babe. don't come at me later like "wait, what unit". i told you. 💀

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👑 SEE ALSO 👑

• Kernel file ./kernel/time/sleep_timeout.c — the source, the origin story, the mothership 🧚
• schedule_timeout(9)
• schedule_timeout_interruptible(9)
• schedule_timeout_killable(9)
• schedule_timeout_uninterruptible(9)
• schedule_timeout_idle(9)
• schedule_hrtimeout_range_clock(9)
• schedule_hrtimeout_range(9)
• schedule_hrtimeout(9)
• msleep(9)
• msleep_interruptible(9)

the whole scheduling friend group 😌 iykyk 💖

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🍓 aaaand that's the page!! brought to you by the lovely humans of ./kernel/time, dropping October 2026 — see you in the next manpage, bestie, mwah 💋✨🌷 sleep well (for somewhere between min and max usecs) 💤🌈