block/bfq-iosched.c

File Facts

System

Linux kernel

Corpus path

block/bfq-iosched.c

Extension

.c

Size

270457 bytes

Lines

7683

Domain

Representative Device Path

Bucket

PCIe NVMe Storage Path

Inferred role

Representative Device Path: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Part of the selected hardware vertical slice: PCI discovery, driver binding, NVMe queues, block requests, DMA, interrupts, and completion.

• Part of the selected hardware vertical slice: PCI discovery, driver binding, NVMe queues, block requests, DMA, interrupts, and completion.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/module.h
• linux/slab.h
• linux/blkdev.h
• linux/cgroup.h
• linux/ktime.h
• linux/rbtree.h
• linux/ioprio.h
• linux/sbitmap.h
• linux/delay.h
• linux/backing-dev.h
• trace/events/block.h
• elevator.h
• blk.h
• blk-mq.h
• blk-mq-sched.h
• bfq-iosched.h
• blk-wbt.h

Detected Declarations

• function bic_set_bfqq
• function bfq_schedule_dispatch
• function bfqq_request_over_limit
• function bfqq_request_over_limit
• function sync
• function queue
• function bfq_rq_pos_tree_lookup
• function bfq_too_late_for_merging
• function likely
• function throughput
• function bfq_weights_tree_add
• function bfq_weights_tree_add
• function bfq_serv_to_charge
• function request
• function bfq_wr_duration
• function switch_back_to_interactive_wr
• function bfq_bfqq_resume_state
• function bfqq_process_refs
• function bfq_reset_burst_list
• function bfq_handle_burst
• function bfq_add_to_burst
• function purpose
• function bfq_bfqq_budget_left
• function bfq_max_budget
• function budget
• function receives
• function bfq_bfqq_budget_left
• function bfq_smallest_from_now
• function bfq_update_bfqq_wr_on_rq_arrival
• function bfq_bfqq_idle_for_long_time
• function bfq_bfqq_higher_class_or_weight
• function bfq_actuator_index
• function bfq_bfqq_handle_idle_busy_switch
• function time_is_before_jiffies
• function bfq_reset_inject_limit
• function bfq_update_io_intensity
• function bfq_select_queue
• function bfq_add_request
• function get_sdist
• function bfq_remove_request
• function bfq_bio_merge
• function bfq_request_merge
• function bfq_request_merged
• function table
• function bfq_bfqq_end_wr
• function bfq_end_wr_async_queues
• function bfq_end_wr
• function bfq_io_struct_pos

Annotated Snippet

module_init(bfq_init);
module_exit(bfq_exit);

MODULE_AUTHOR("Paolo Valente");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MQ Budget Fair Queueing I/O Scheduler");

Annotation

• Immediate include surface: `linux/module.h`, `linux/slab.h`, `linux/blkdev.h`, `linux/cgroup.h`, `linux/ktime.h`, `linux/rbtree.h`, `linux/ioprio.h`, `linux/sbitmap.h`.
• Detected declarations: `function bic_set_bfqq`, `function bfq_schedule_dispatch`, `function bfqq_request_over_limit`, `function bfqq_request_over_limit`, `function sync`, `function queue`, `function bfq_rq_pos_tree_lookup`, `function bfq_too_late_for_merging`, `function likely`, `function throughput`.
• Atlas domain: Representative Device Path / PCIe NVMe Storage Path.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.