STRUCT BFQ_SERVICE_TREE(9)

💖 struct bfq_service_tree(9) 💖

okay so welcome to the Kernel API Manual, bestie — this is the struct bfq_service_tree(9) page, and it's giving per-class scheduler realness ✨

💖 NAME 💖

struct bfq_service_tree — per ioprio_class service tree. That's the whole name vibe 🎀

✨ SYNOPSIS ✨

Here's the struct, no cap — fields exactly as they are, don't touch a character:

       struct bfq_service_tree {
           struct rb_root active;
           struct rb_root idle;
           struct bfq_entity *first_idle;
           struct bfq_entity *last_idle;
           u64 vtime;
           unsigned long wsum;
        };

🫶 Members 🫶

No extra per-member notes here — the member lineup is the struct up in SYNOPSIS, and that's it. The squad is all right there 💅

🌸 Description 🌸

Each service tree represents a B-WF2Q+ scheduler on its own. That's the main-character energy: one scheduler per tree, no sharing.

Every ioprio_class has its own independent scheduler, and so its own bfq_service_tree. Independent means independent, bestie — they're not sharing a scheduler.

All the fields are protected by the queue lock of the containing bfqd. So yeah, lock discipline is the vibe check here 🫶

🔥 SEE ALSO 🔥

Kernel file ./block/bfq-iosched.h — go peek, iykyk:

• struct bfq_sched_data(9)
• struct bfq_weight_counter(9)
• struct bfq_entity(9)
• struct bfq_ttime(9)
• struct bfq_queue(9)
• struct bfq_io_cq(9)
• struct bfq_data(9)
• struct bfq_group(9)

mwah 💋 — this little page came from the ./block source, dated October 2026, and it's all about struct bfq_service_tree(9). Periodt 🎀