htb_do_events(9)

💅 htb_do_events(9) 💅

okay so bestie, welcome to the Kernel API Manual — today's main character is htb_do_events(9), and honestly? she's the one quietly keeping the whole HTB class-level situation from falling apart. let's get into it 🎀

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✨ NAME ✨

htb_do_events — makes mode changes to classes at the level. yeah. that's the whole vibe. she shows up, she flips modes, she leaves. iconic behavior only 💅

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🌸 SYNOPSIS 🌸

s64 htb_do_events (struct htb_sched *q , const int level , unsigned long
start );

like, look at that signature. s64 return, three args, zero drama (okay maybe a lil drama, see NOTE below 😭). periodt.

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🦋 ARGUMENTS 🦋

• q — the priority event queue 💖 this is the whole reason we're here.
• level — tells you which wait_pq lives inside q->hlevel. yes, the specific one. don't @ me.
• start — the start jiffies ⏱️ the clock we're measuring from, bestie.

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💀 DESCRIPTION 💀

so what does she actually do? she scans the event queue for pending events and applies them. that's it. that's the job. no cap 🫶

and then — because she's thoughtful like that — she returns the time of the next pending event. but read the fine print bestie, because the return value is giving three different moods:

• 0 when there's no event in the pq
• q->now when there are too many events 😭 (yes, too many. she said enough.)

lowkey the most emotionally complex return value in sch_htb.c. ngl.

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⭐ NOTE ⭐

applied are the events whose cl->pq_key <= q->now. that's the vibe check they have to pass to get processed. if you're not at or before now, you're not getting applied. sorry babe 🎀

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🌈 SEE ALSO 🌈

the kernel file ./net/sched/sch_htb.c and her whole friend group, fr fr:

• htb_classify(9)
• htb_add_to_id_tree(9)
• htb_add_to_wait_tree(9)
• htb_next_rb_node(9)
• htb_add_class_to_row(9)
• htb_remove_class_from_row(9)
• htb_activate_prios(9)
• htb_deactivate_prios(9)
• htb_class_mode(9)
• htb_change_class_mode(9)
• htb_activate(9)
• htb_deactivate(9)
• htb_charge_class(9)
• htb_lookup_leaf(9)

every single one of them. iykyk 💜

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and that's the page!! sourced straight from ./net/sched, dated October 2026 — write it down bestie, that's the receipt 🧚✨ bye ily 🫶