STRUCT BFQ_DATA(9)

Hey bestie, welcome to the struct bfq_data(9) page from the Kernel API Manual — yes, this is the per-device data structure glow-up, and we're keeping every single field, periodt. 💅✨

💖 NAME 💖

struct bfq_data — the per-device data structure. 🎀

✨ SYNOPSIS ✨

Okay so here's the whole struct exactly as it is, no cap. Every field is invited to the group chat: 🫶

       struct bfq_data {
           struct request_queue *queue;
           struct list_head dispatch;
           struct bfq_group *root_group;
           struct rb_root_cached queue_weights_tree;
         #ifdef CONFIG_BFQ_GROUP_IOSCHED;
           unsigned int num_groups_with_pending_reqs;
         #endif;
           unsigned int busy_queues[3];
           int wr_busy_queues;
           int queued;
           int tot_rq_in_driver;
           int rq_in_driver[BFQ_MAX_ACTUATORS];
           bool nonrot_with_queueing;
           int max_rq_in_driver;
           int hw_tag_samples;
           int hw_tag;
           int budgets_assigned;
           struct hrtimer idle_slice_timer;
           struct bfq_queue *in_service_queue;
           sector_t last_position;
           sector_t in_serv_last_pos;
           u64 last_completion;
           struct bfq_queue *last_completed_rq_bfqq;
           struct bfq_queue *last_bfqq_created;
           u64 last_empty_occupied_ns;
           bool wait_dispatch;
           struct request *waited_rq;
           bool rqs_injected;
           u64 first_dispatch;
           u64 last_dispatch;
           ktime_t last_budget_start;
           ktime_t last_idling_start;
           unsigned long last_idling_start_jiffies;
           int peak_rate_samples;
           u32 sequential_samples;
           u64 tot_sectors_dispatched;
           u32 last_rq_max_size;
           u64 delta_from_first;
           u32 peak_rate;
           int bfq_max_budget;
           struct list_head active_list[BFQ_MAX_ACTUATORS];
           struct list_head idle_list;
           u64 bfq_fifo_expire[2];
           unsigned int bfq_back_penalty;
           unsigned int bfq_back_max;
           u32 bfq_slice_idle;
           int bfq_user_max_budget;
           unsigned int bfq_timeout;
           bool strict_guarantees;
           unsigned long last_ins_in_burst;
           unsigned long bfq_burst_interval;
           int burst_size;
           struct bfq_entity *burst_parent_entity;
           unsigned long bfq_large_burst_thresh;
           bool large_burst;
           struct hlist_head burst_list;
           bool low_latency;
           unsigned int bfq_wr_coeff;
           unsigned int bfq_wr_rt_max_time;
           unsigned int bfq_wr_min_idle_time;
           unsigned long bfq_wr_min_inter_arr_async;
           unsigned int bfq_wr_max_softrt_rate;
           u64 rate_dur_prod;
           struct bfq_queue oom_bfqq;
           spinlock_t lock;
           struct bfq_io_cq *bio_bic;
           struct bfq_queue *bio_bfqq;
           unsigned int async_depths[2][2];
           unsigned int num_actuators;
           sector_t sector[BFQ_MAX_ACTUATORS];
           sector_t nr_sectors[BFQ_MAX_ACTUATORS];
           struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
           unsigned int actuator_load_threshold;
        };

🫶 Members 🫶

Members is literally the whole field list in the struct above, bestie — don't skip a single one, iykyk. 🌸

🌸 Description 🌸

All the fields are protected by lock. That's the safety tea, and it's giving very serious synchronization energy. 🔒💖

🔥 SEE ALSO 🔥

Kernel file ./block/bfq-iosched.h — and the whole friend group: struct bfq_service_tree(9), 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_group(9). Go read them, they're iconic. 👑

Signed with sparkles: source/version ./block, date October 2026, page struct bfq_data(9). 💖🦋🎀