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2533 lines
68 KiB
2533 lines
68 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Interface for controlling IO bandwidth on a request queue |
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* |
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* Copyright (C) 2010 Vivek Goyal <[email protected]> |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/blkdev.h> |
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#include <linux/bio.h> |
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#include <linux/blktrace_api.h> |
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#include <linux/blk-cgroup.h> |
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#include "blk.h" |
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#include "blk-cgroup-rwstat.h" |
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/* Max dispatch from a group in 1 round */ |
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#define THROTL_GRP_QUANTUM 8 |
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|
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/* Total max dispatch from all groups in one round */ |
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#define THROTL_QUANTUM 32 |
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/* Throttling is performed over a slice and after that slice is renewed */ |
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#define DFL_THROTL_SLICE_HD (HZ / 10) |
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#define DFL_THROTL_SLICE_SSD (HZ / 50) |
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#define MAX_THROTL_SLICE (HZ) |
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#define MAX_IDLE_TIME (5L * 1000 * 1000) /* 5 s */ |
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#define MIN_THROTL_BPS (320 * 1024) |
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#define MIN_THROTL_IOPS (10) |
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#define DFL_LATENCY_TARGET (-1L) |
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#define DFL_IDLE_THRESHOLD (0) |
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#define DFL_HD_BASELINE_LATENCY (4000L) /* 4ms */ |
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#define LATENCY_FILTERED_SSD (0) |
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/* |
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* For HD, very small latency comes from sequential IO. Such IO is helpless to |
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* help determine if its IO is impacted by others, hence we ignore the IO |
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*/ |
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#define LATENCY_FILTERED_HD (1000L) /* 1ms */ |
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static struct blkcg_policy blkcg_policy_throtl; |
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/* A workqueue to queue throttle related work */ |
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static struct workqueue_struct *kthrotld_workqueue; |
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/* |
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* To implement hierarchical throttling, throtl_grps form a tree and bios |
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* are dispatched upwards level by level until they reach the top and get |
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* issued. When dispatching bios from the children and local group at each |
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* level, if the bios are dispatched into a single bio_list, there's a risk |
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* of a local or child group which can queue many bios at once filling up |
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* the list starving others. |
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* |
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* To avoid such starvation, dispatched bios are queued separately |
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* according to where they came from. When they are again dispatched to |
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* the parent, they're popped in round-robin order so that no single source |
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* hogs the dispatch window. |
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* |
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* throtl_qnode is used to keep the queued bios separated by their sources. |
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* Bios are queued to throtl_qnode which in turn is queued to |
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* throtl_service_queue and then dispatched in round-robin order. |
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* |
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* It's also used to track the reference counts on blkg's. A qnode always |
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* belongs to a throtl_grp and gets queued on itself or the parent, so |
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* incrementing the reference of the associated throtl_grp when a qnode is |
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* queued and decrementing when dequeued is enough to keep the whole blkg |
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* tree pinned while bios are in flight. |
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*/ |
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struct throtl_qnode { |
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struct list_head node; /* service_queue->queued[] */ |
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struct bio_list bios; /* queued bios */ |
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struct throtl_grp *tg; /* tg this qnode belongs to */ |
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}; |
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struct throtl_service_queue { |
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struct throtl_service_queue *parent_sq; /* the parent service_queue */ |
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/* |
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* Bios queued directly to this service_queue or dispatched from |
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* children throtl_grp's. |
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*/ |
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struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ |
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unsigned int nr_queued[2]; /* number of queued bios */ |
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|
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/* |
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* RB tree of active children throtl_grp's, which are sorted by |
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* their ->disptime. |
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*/ |
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struct rb_root_cached pending_tree; /* RB tree of active tgs */ |
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unsigned int nr_pending; /* # queued in the tree */ |
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unsigned long first_pending_disptime; /* disptime of the first tg */ |
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struct timer_list pending_timer; /* fires on first_pending_disptime */ |
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}; |
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enum tg_state_flags { |
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THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ |
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THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ |
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}; |
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#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) |
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enum { |
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LIMIT_LOW, |
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LIMIT_MAX, |
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LIMIT_CNT, |
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}; |
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struct throtl_grp { |
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/* must be the first member */ |
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struct blkg_policy_data pd; |
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/* active throtl group service_queue member */ |
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struct rb_node rb_node; |
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/* throtl_data this group belongs to */ |
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struct throtl_data *td; |
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|
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/* this group's service queue */ |
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struct throtl_service_queue service_queue; |
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/* |
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* qnode_on_self is used when bios are directly queued to this |
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* throtl_grp so that local bios compete fairly with bios |
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* dispatched from children. qnode_on_parent is used when bios are |
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* dispatched from this throtl_grp into its parent and will compete |
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* with the sibling qnode_on_parents and the parent's |
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* qnode_on_self. |
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*/ |
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struct throtl_qnode qnode_on_self[2]; |
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struct throtl_qnode qnode_on_parent[2]; |
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/* |
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* Dispatch time in jiffies. This is the estimated time when group |
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* will unthrottle and is ready to dispatch more bio. It is used as |
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* key to sort active groups in service tree. |
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*/ |
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unsigned long disptime; |
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unsigned int flags; |
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/* are there any throtl rules between this group and td? */ |
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bool has_rules[2]; |
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/* internally used bytes per second rate limits */ |
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uint64_t bps[2][LIMIT_CNT]; |
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/* user configured bps limits */ |
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uint64_t bps_conf[2][LIMIT_CNT]; |
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|
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/* internally used IOPS limits */ |
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unsigned int iops[2][LIMIT_CNT]; |
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/* user configured IOPS limits */ |
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unsigned int iops_conf[2][LIMIT_CNT]; |
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/* Number of bytes dispatched in current slice */ |
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uint64_t bytes_disp[2]; |
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/* Number of bio's dispatched in current slice */ |
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unsigned int io_disp[2]; |
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unsigned long last_low_overflow_time[2]; |
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uint64_t last_bytes_disp[2]; |
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unsigned int last_io_disp[2]; |
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unsigned long last_check_time; |
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unsigned long latency_target; /* us */ |
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unsigned long latency_target_conf; /* us */ |
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/* When did we start a new slice */ |
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unsigned long slice_start[2]; |
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unsigned long slice_end[2]; |
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unsigned long last_finish_time; /* ns / 1024 */ |
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unsigned long checked_last_finish_time; /* ns / 1024 */ |
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unsigned long avg_idletime; /* ns / 1024 */ |
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unsigned long idletime_threshold; /* us */ |
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unsigned long idletime_threshold_conf; /* us */ |
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unsigned int bio_cnt; /* total bios */ |
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unsigned int bad_bio_cnt; /* bios exceeding latency threshold */ |
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unsigned long bio_cnt_reset_time; |
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atomic_t io_split_cnt[2]; |
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atomic_t last_io_split_cnt[2]; |
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struct blkg_rwstat stat_bytes; |
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struct blkg_rwstat stat_ios; |
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}; |
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/* We measure latency for request size from <= 4k to >= 1M */ |
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#define LATENCY_BUCKET_SIZE 9 |
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struct latency_bucket { |
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unsigned long total_latency; /* ns / 1024 */ |
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int samples; |
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}; |
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struct avg_latency_bucket { |
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unsigned long latency; /* ns / 1024 */ |
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bool valid; |
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}; |
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struct throtl_data |
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{ |
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/* service tree for active throtl groups */ |
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struct throtl_service_queue service_queue; |
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struct request_queue *queue; |
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/* Total Number of queued bios on READ and WRITE lists */ |
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unsigned int nr_queued[2]; |
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unsigned int throtl_slice; |
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/* Work for dispatching throttled bios */ |
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struct work_struct dispatch_work; |
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unsigned int limit_index; |
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bool limit_valid[LIMIT_CNT]; |
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unsigned long low_upgrade_time; |
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unsigned long low_downgrade_time; |
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unsigned int scale; |
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struct latency_bucket tmp_buckets[2][LATENCY_BUCKET_SIZE]; |
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struct avg_latency_bucket avg_buckets[2][LATENCY_BUCKET_SIZE]; |
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struct latency_bucket __percpu *latency_buckets[2]; |
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unsigned long last_calculate_time; |
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unsigned long filtered_latency; |
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bool track_bio_latency; |
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}; |
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static void throtl_pending_timer_fn(struct timer_list *t); |
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static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
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{ |
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return pd ? container_of(pd, struct throtl_grp, pd) : NULL; |
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} |
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static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
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{ |
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return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
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} |
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static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
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{ |
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return pd_to_blkg(&tg->pd); |
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} |
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/** |
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* sq_to_tg - return the throl_grp the specified service queue belongs to |
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* @sq: the throtl_service_queue of interest |
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* |
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* Return the throtl_grp @sq belongs to. If @sq is the top-level one |
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* embedded in throtl_data, %NULL is returned. |
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*/ |
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static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) |
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{ |
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if (sq && sq->parent_sq) |
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return container_of(sq, struct throtl_grp, service_queue); |
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else |
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return NULL; |
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} |
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|
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/** |
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* sq_to_td - return throtl_data the specified service queue belongs to |
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* @sq: the throtl_service_queue of interest |
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* |
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* A service_queue can be embedded in either a throtl_grp or throtl_data. |
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* Determine the associated throtl_data accordingly and return it. |
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*/ |
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static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) |
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{ |
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struct throtl_grp *tg = sq_to_tg(sq); |
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if (tg) |
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return tg->td; |
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else |
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return container_of(sq, struct throtl_data, service_queue); |
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} |
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/* |
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* cgroup's limit in LIMIT_MAX is scaled if low limit is set. This scale is to |
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* make the IO dispatch more smooth. |
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* Scale up: linearly scale up according to lapsed time since upgrade. For |
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* every throtl_slice, the limit scales up 1/2 .low limit till the |
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* limit hits .max limit |
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* Scale down: exponentially scale down if a cgroup doesn't hit its .low limit |
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*/ |
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static uint64_t throtl_adjusted_limit(uint64_t low, struct throtl_data *td) |
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{ |
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/* arbitrary value to avoid too big scale */ |
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if (td->scale < 4096 && time_after_eq(jiffies, |
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td->low_upgrade_time + td->scale * td->throtl_slice)) |
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td->scale = (jiffies - td->low_upgrade_time) / td->throtl_slice; |
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return low + (low >> 1) * td->scale; |
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} |
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static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
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{ |
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struct blkcg_gq *blkg = tg_to_blkg(tg); |
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struct throtl_data *td; |
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uint64_t ret; |
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if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) |
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return U64_MAX; |
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td = tg->td; |
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ret = tg->bps[rw][td->limit_index]; |
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if (ret == 0 && td->limit_index == LIMIT_LOW) { |
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/* intermediate node or iops isn't 0 */ |
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if (!list_empty(&blkg->blkcg->css.children) || |
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tg->iops[rw][td->limit_index]) |
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return U64_MAX; |
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else |
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return MIN_THROTL_BPS; |
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} |
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if (td->limit_index == LIMIT_MAX && tg->bps[rw][LIMIT_LOW] && |
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tg->bps[rw][LIMIT_LOW] != tg->bps[rw][LIMIT_MAX]) { |
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uint64_t adjusted; |
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adjusted = throtl_adjusted_limit(tg->bps[rw][LIMIT_LOW], td); |
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ret = min(tg->bps[rw][LIMIT_MAX], adjusted); |
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} |
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return ret; |
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} |
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static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) |
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{ |
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struct blkcg_gq *blkg = tg_to_blkg(tg); |
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struct throtl_data *td; |
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unsigned int ret; |
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if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) |
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return UINT_MAX; |
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td = tg->td; |
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ret = tg->iops[rw][td->limit_index]; |
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if (ret == 0 && tg->td->limit_index == LIMIT_LOW) { |
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/* intermediate node or bps isn't 0 */ |
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if (!list_empty(&blkg->blkcg->css.children) || |
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tg->bps[rw][td->limit_index]) |
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return UINT_MAX; |
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else |
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return MIN_THROTL_IOPS; |
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} |
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if (td->limit_index == LIMIT_MAX && tg->iops[rw][LIMIT_LOW] && |
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tg->iops[rw][LIMIT_LOW] != tg->iops[rw][LIMIT_MAX]) { |
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uint64_t adjusted; |
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adjusted = throtl_adjusted_limit(tg->iops[rw][LIMIT_LOW], td); |
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if (adjusted > UINT_MAX) |
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adjusted = UINT_MAX; |
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ret = min_t(unsigned int, tg->iops[rw][LIMIT_MAX], adjusted); |
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} |
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return ret; |
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} |
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#define request_bucket_index(sectors) \ |
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clamp_t(int, order_base_2(sectors) - 3, 0, LATENCY_BUCKET_SIZE - 1) |
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/** |
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* throtl_log - log debug message via blktrace |
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* @sq: the service_queue being reported |
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* @fmt: printf format string |
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* @args: printf args |
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* |
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* The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a |
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* throtl_grp; otherwise, just "throtl". |
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*/ |
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#define throtl_log(sq, fmt, args...) do { \ |
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struct throtl_grp *__tg = sq_to_tg((sq)); \ |
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struct throtl_data *__td = sq_to_td((sq)); \ |
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\ |
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(void)__td; \ |
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if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
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break; \ |
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if ((__tg)) { \ |
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blk_add_cgroup_trace_msg(__td->queue, \ |
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tg_to_blkg(__tg)->blkcg, "throtl " fmt, ##args);\ |
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} else { \ |
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blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ |
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} \ |
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} while (0) |
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static inline unsigned int throtl_bio_data_size(struct bio *bio) |
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{ |
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/* assume it's one sector */ |
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if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) |
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return 512; |
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return bio->bi_iter.bi_size; |
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} |
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static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
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{ |
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INIT_LIST_HEAD(&qn->node); |
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bio_list_init(&qn->bios); |
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qn->tg = tg; |
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} |
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/** |
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* throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it |
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* @bio: bio being added |
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* @qn: qnode to add bio to |
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* @queued: the service_queue->queued[] list @qn belongs to |
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* |
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* Add @bio to @qn and put @qn on @queued if it's not already on. |
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* @qn->tg's reference count is bumped when @qn is activated. See the |
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* comment on top of throtl_qnode definition for details. |
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*/ |
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static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, |
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struct list_head *queued) |
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{ |
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bio_list_add(&qn->bios, bio); |
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if (list_empty(&qn->node)) { |
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list_add_tail(&qn->node, queued); |
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blkg_get(tg_to_blkg(qn->tg)); |
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} |
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} |
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|
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/** |
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* throtl_peek_queued - peek the first bio on a qnode list |
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* @queued: the qnode list to peek |
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*/ |
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static struct bio *throtl_peek_queued(struct list_head *queued) |
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{ |
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struct throtl_qnode *qn; |
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struct bio *bio; |
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|
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if (list_empty(queued)) |
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return NULL; |
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|
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qn = list_first_entry(queued, struct throtl_qnode, node); |
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bio = bio_list_peek(&qn->bios); |
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WARN_ON_ONCE(!bio); |
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return bio; |
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} |
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|
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/** |
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* throtl_pop_queued - pop the first bio form a qnode list |
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* @queued: the qnode list to pop a bio from |
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* @tg_to_put: optional out argument for throtl_grp to put |
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* |
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* Pop the first bio from the qnode list @queued. After popping, the first |
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* qnode is removed from @queued if empty or moved to the end of @queued so |
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* that the popping order is round-robin. |
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* |
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* When the first qnode is removed, its associated throtl_grp should be put |
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* too. If @tg_to_put is NULL, this function automatically puts it; |
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* otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is |
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* responsible for putting it. |
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*/ |
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static struct bio *throtl_pop_queued(struct list_head *queued, |
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struct throtl_grp **tg_to_put) |
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{ |
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struct throtl_qnode *qn; |
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struct bio *bio; |
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|
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if (list_empty(queued)) |
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return NULL; |
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|
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qn = list_first_entry(queued, struct throtl_qnode, node); |
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bio = bio_list_pop(&qn->bios); |
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WARN_ON_ONCE(!bio); |
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|
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if (bio_list_empty(&qn->bios)) { |
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list_del_init(&qn->node); |
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if (tg_to_put) |
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*tg_to_put = qn->tg; |
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else |
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blkg_put(tg_to_blkg(qn->tg)); |
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} else { |
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list_move_tail(&qn->node, queued); |
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} |
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|
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return bio; |
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} |
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|
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/* init a service_queue, assumes the caller zeroed it */ |
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static void throtl_service_queue_init(struct throtl_service_queue *sq) |
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{ |
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INIT_LIST_HEAD(&sq->queued[0]); |
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INIT_LIST_HEAD(&sq->queued[1]); |
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sq->pending_tree = RB_ROOT_CACHED; |
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timer_setup(&sq->pending_timer, throtl_pending_timer_fn, 0); |
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} |
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|
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static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, |
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struct request_queue *q, |
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struct blkcg *blkcg) |
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{ |
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struct throtl_grp *tg; |
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int rw; |
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|
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tg = kzalloc_node(sizeof(*tg), gfp, q->node); |
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if (!tg) |
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return NULL; |
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|
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if (blkg_rwstat_init(&tg->stat_bytes, gfp)) |
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goto err_free_tg; |
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|
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if (blkg_rwstat_init(&tg->stat_ios, gfp)) |
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goto err_exit_stat_bytes; |
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throtl_service_queue_init(&tg->service_queue); |
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|
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for (rw = READ; rw <= WRITE; rw++) { |
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throtl_qnode_init(&tg->qnode_on_self[rw], tg); |
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throtl_qnode_init(&tg->qnode_on_parent[rw], tg); |
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} |
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|
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RB_CLEAR_NODE(&tg->rb_node); |
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tg->bps[READ][LIMIT_MAX] = U64_MAX; |
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tg->bps[WRITE][LIMIT_MAX] = U64_MAX; |
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tg->iops[READ][LIMIT_MAX] = UINT_MAX; |
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tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; |
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tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
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tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; |
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tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; |
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tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; |
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/* LIMIT_LOW will have default value 0 */ |
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|
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tg->latency_target = DFL_LATENCY_TARGET; |
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tg->latency_target_conf = DFL_LATENCY_TARGET; |
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tg->idletime_threshold = DFL_IDLE_THRESHOLD; |
|
tg->idletime_threshold_conf = DFL_IDLE_THRESHOLD; |
|
|
|
return &tg->pd; |
|
|
|
err_exit_stat_bytes: |
|
blkg_rwstat_exit(&tg->stat_bytes); |
|
err_free_tg: |
|
kfree(tg); |
|
return NULL; |
|
} |
|
|
|
static void throtl_pd_init(struct blkg_policy_data *pd) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
struct blkcg_gq *blkg = tg_to_blkg(tg); |
|
struct throtl_data *td = blkg->q->td; |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
|
|
/* |
|
* If on the default hierarchy, we switch to properly hierarchical |
|
* behavior where limits on a given throtl_grp are applied to the |
|
* whole subtree rather than just the group itself. e.g. If 16M |
|
* read_bps limit is set on the root group, the whole system can't |
|
* exceed 16M for the device. |
|
* |
|
* If not on the default hierarchy, the broken flat hierarchy |
|
* behavior is retained where all throtl_grps are treated as if |
|
* they're all separate root groups right below throtl_data. |
|
* Limits of a group don't interact with limits of other groups |
|
* regardless of the position of the group in the hierarchy. |
|
*/ |
|
sq->parent_sq = &td->service_queue; |
|
if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
|
sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
|
tg->td = td; |
|
} |
|
|
|
/* |
|
* Set has_rules[] if @tg or any of its parents have limits configured. |
|
* This doesn't require walking up to the top of the hierarchy as the |
|
* parent's has_rules[] is guaranteed to be correct. |
|
*/ |
|
static void tg_update_has_rules(struct throtl_grp *tg) |
|
{ |
|
struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); |
|
struct throtl_data *td = tg->td; |
|
int rw; |
|
|
|
for (rw = READ; rw <= WRITE; rw++) |
|
tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || |
|
(td->limit_valid[td->limit_index] && |
|
(tg_bps_limit(tg, rw) != U64_MAX || |
|
tg_iops_limit(tg, rw) != UINT_MAX)); |
|
} |
|
|
|
static void throtl_pd_online(struct blkg_policy_data *pd) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
/* |
|
* We don't want new groups to escape the limits of its ancestors. |
|
* Update has_rules[] after a new group is brought online. |
|
*/ |
|
tg_update_has_rules(tg); |
|
} |
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
static void blk_throtl_update_limit_valid(struct throtl_data *td) |
|
{ |
|
struct cgroup_subsys_state *pos_css; |
|
struct blkcg_gq *blkg; |
|
bool low_valid = false; |
|
|
|
rcu_read_lock(); |
|
blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { |
|
struct throtl_grp *tg = blkg_to_tg(blkg); |
|
|
|
if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || |
|
tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) { |
|
low_valid = true; |
|
break; |
|
} |
|
} |
|
rcu_read_unlock(); |
|
|
|
td->limit_valid[LIMIT_LOW] = low_valid; |
|
} |
|
#else |
|
static inline void blk_throtl_update_limit_valid(struct throtl_data *td) |
|
{ |
|
} |
|
#endif |
|
|
|
static void throtl_upgrade_state(struct throtl_data *td); |
|
static void throtl_pd_offline(struct blkg_policy_data *pd) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
|
|
tg->bps[READ][LIMIT_LOW] = 0; |
|
tg->bps[WRITE][LIMIT_LOW] = 0; |
|
tg->iops[READ][LIMIT_LOW] = 0; |
|
tg->iops[WRITE][LIMIT_LOW] = 0; |
|
|
|
blk_throtl_update_limit_valid(tg->td); |
|
|
|
if (!tg->td->limit_valid[tg->td->limit_index]) |
|
throtl_upgrade_state(tg->td); |
|
} |
|
|
|
static void throtl_pd_free(struct blkg_policy_data *pd) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
|
|
del_timer_sync(&tg->service_queue.pending_timer); |
|
blkg_rwstat_exit(&tg->stat_bytes); |
|
blkg_rwstat_exit(&tg->stat_ios); |
|
kfree(tg); |
|
} |
|
|
|
static struct throtl_grp * |
|
throtl_rb_first(struct throtl_service_queue *parent_sq) |
|
{ |
|
struct rb_node *n; |
|
|
|
n = rb_first_cached(&parent_sq->pending_tree); |
|
WARN_ON_ONCE(!n); |
|
if (!n) |
|
return NULL; |
|
return rb_entry_tg(n); |
|
} |
|
|
|
static void throtl_rb_erase(struct rb_node *n, |
|
struct throtl_service_queue *parent_sq) |
|
{ |
|
rb_erase_cached(n, &parent_sq->pending_tree); |
|
RB_CLEAR_NODE(n); |
|
--parent_sq->nr_pending; |
|
} |
|
|
|
static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
|
{ |
|
struct throtl_grp *tg; |
|
|
|
tg = throtl_rb_first(parent_sq); |
|
if (!tg) |
|
return; |
|
|
|
parent_sq->first_pending_disptime = tg->disptime; |
|
} |
|
|
|
static void tg_service_queue_add(struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
|
struct rb_node **node = &parent_sq->pending_tree.rb_root.rb_node; |
|
struct rb_node *parent = NULL; |
|
struct throtl_grp *__tg; |
|
unsigned long key = tg->disptime; |
|
bool leftmost = true; |
|
|
|
while (*node != NULL) { |
|
parent = *node; |
|
__tg = rb_entry_tg(parent); |
|
|
|
if (time_before(key, __tg->disptime)) |
|
node = &parent->rb_left; |
|
else { |
|
node = &parent->rb_right; |
|
leftmost = false; |
|
} |
|
} |
|
|
|
rb_link_node(&tg->rb_node, parent, node); |
|
rb_insert_color_cached(&tg->rb_node, &parent_sq->pending_tree, |
|
leftmost); |
|
} |
|
|
|
static void throtl_enqueue_tg(struct throtl_grp *tg) |
|
{ |
|
if (!(tg->flags & THROTL_TG_PENDING)) { |
|
tg_service_queue_add(tg); |
|
tg->flags |= THROTL_TG_PENDING; |
|
tg->service_queue.parent_sq->nr_pending++; |
|
} |
|
} |
|
|
|
static void throtl_dequeue_tg(struct throtl_grp *tg) |
|
{ |
|
if (tg->flags & THROTL_TG_PENDING) { |
|
throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
|
tg->flags &= ~THROTL_TG_PENDING; |
|
} |
|
} |
|
|
|
/* Call with queue lock held */ |
|
static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
|
unsigned long expires) |
|
{ |
|
unsigned long max_expire = jiffies + 8 * sq_to_td(sq)->throtl_slice; |
|
|
|
/* |
|
* Since we are adjusting the throttle limit dynamically, the sleep |
|
* time calculated according to previous limit might be invalid. It's |
|
* possible the cgroup sleep time is very long and no other cgroups |
|
* have IO running so notify the limit changes. Make sure the cgroup |
|
* doesn't sleep too long to avoid the missed notification. |
|
*/ |
|
if (time_after(expires, max_expire)) |
|
expires = max_expire; |
|
mod_timer(&sq->pending_timer, expires); |
|
throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", |
|
expires - jiffies, jiffies); |
|
} |
|
|
|
/** |
|
* throtl_schedule_next_dispatch - schedule the next dispatch cycle |
|
* @sq: the service_queue to schedule dispatch for |
|
* @force: force scheduling |
|
* |
|
* Arm @sq->pending_timer so that the next dispatch cycle starts on the |
|
* dispatch time of the first pending child. Returns %true if either timer |
|
* is armed or there's no pending child left. %false if the current |
|
* dispatch window is still open and the caller should continue |
|
* dispatching. |
|
* |
|
* If @force is %true, the dispatch timer is always scheduled and this |
|
* function is guaranteed to return %true. This is to be used when the |
|
* caller can't dispatch itself and needs to invoke pending_timer |
|
* unconditionally. Note that forced scheduling is likely to induce short |
|
* delay before dispatch starts even if @sq->first_pending_disptime is not |
|
* in the future and thus shouldn't be used in hot paths. |
|
*/ |
|
static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, |
|
bool force) |
|
{ |
|
/* any pending children left? */ |
|
if (!sq->nr_pending) |
|
return true; |
|
|
|
update_min_dispatch_time(sq); |
|
|
|
/* is the next dispatch time in the future? */ |
|
if (force || time_after(sq->first_pending_disptime, jiffies)) { |
|
throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
|
return true; |
|
} |
|
|
|
/* tell the caller to continue dispatching */ |
|
return false; |
|
} |
|
|
|
static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
|
bool rw, unsigned long start) |
|
{ |
|
tg->bytes_disp[rw] = 0; |
|
tg->io_disp[rw] = 0; |
|
|
|
atomic_set(&tg->io_split_cnt[rw], 0); |
|
|
|
/* |
|
* Previous slice has expired. We must have trimmed it after last |
|
* bio dispatch. That means since start of last slice, we never used |
|
* that bandwidth. Do try to make use of that bandwidth while giving |
|
* credit. |
|
*/ |
|
if (time_after_eq(start, tg->slice_start[rw])) |
|
tg->slice_start[rw] = start; |
|
|
|
tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
|
throtl_log(&tg->service_queue, |
|
"[%c] new slice with credit start=%lu end=%lu jiffies=%lu", |
|
rw == READ ? 'R' : 'W', tg->slice_start[rw], |
|
tg->slice_end[rw], jiffies); |
|
} |
|
|
|
static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
|
{ |
|
tg->bytes_disp[rw] = 0; |
|
tg->io_disp[rw] = 0; |
|
tg->slice_start[rw] = jiffies; |
|
tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
|
|
|
atomic_set(&tg->io_split_cnt[rw], 0); |
|
|
|
throtl_log(&tg->service_queue, |
|
"[%c] new slice start=%lu end=%lu jiffies=%lu", |
|
rw == READ ? 'R' : 'W', tg->slice_start[rw], |
|
tg->slice_end[rw], jiffies); |
|
} |
|
|
|
static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
|
unsigned long jiffy_end) |
|
{ |
|
tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
|
} |
|
|
|
static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
|
unsigned long jiffy_end) |
|
{ |
|
throtl_set_slice_end(tg, rw, jiffy_end); |
|
throtl_log(&tg->service_queue, |
|
"[%c] extend slice start=%lu end=%lu jiffies=%lu", |
|
rw == READ ? 'R' : 'W', tg->slice_start[rw], |
|
tg->slice_end[rw], jiffies); |
|
} |
|
|
|
/* Determine if previously allocated or extended slice is complete or not */ |
|
static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
|
{ |
|
if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) |
|
return false; |
|
|
|
return true; |
|
} |
|
|
|
/* Trim the used slices and adjust slice start accordingly */ |
|
static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
|
{ |
|
unsigned long nr_slices, time_elapsed, io_trim; |
|
u64 bytes_trim, tmp; |
|
|
|
BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); |
|
|
|
/* |
|
* If bps are unlimited (-1), then time slice don't get |
|
* renewed. Don't try to trim the slice if slice is used. A new |
|
* slice will start when appropriate. |
|
*/ |
|
if (throtl_slice_used(tg, rw)) |
|
return; |
|
|
|
/* |
|
* A bio has been dispatched. Also adjust slice_end. It might happen |
|
* that initially cgroup limit was very low resulting in high |
|
* slice_end, but later limit was bumped up and bio was dispatched |
|
* sooner, then we need to reduce slice_end. A high bogus slice_end |
|
* is bad because it does not allow new slice to start. |
|
*/ |
|
|
|
throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); |
|
|
|
time_elapsed = jiffies - tg->slice_start[rw]; |
|
|
|
nr_slices = time_elapsed / tg->td->throtl_slice; |
|
|
|
if (!nr_slices) |
|
return; |
|
tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; |
|
do_div(tmp, HZ); |
|
bytes_trim = tmp; |
|
|
|
io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / |
|
HZ; |
|
|
|
if (!bytes_trim && !io_trim) |
|
return; |
|
|
|
if (tg->bytes_disp[rw] >= bytes_trim) |
|
tg->bytes_disp[rw] -= bytes_trim; |
|
else |
|
tg->bytes_disp[rw] = 0; |
|
|
|
if (tg->io_disp[rw] >= io_trim) |
|
tg->io_disp[rw] -= io_trim; |
|
else |
|
tg->io_disp[rw] = 0; |
|
|
|
tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; |
|
|
|
throtl_log(&tg->service_queue, |
|
"[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", |
|
rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, |
|
tg->slice_start[rw], tg->slice_end[rw], jiffies); |
|
} |
|
|
|
static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
|
u32 iops_limit, unsigned long *wait) |
|
{ |
|
bool rw = bio_data_dir(bio); |
|
unsigned int io_allowed; |
|
unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
|
u64 tmp; |
|
|
|
if (iops_limit == UINT_MAX) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
jiffy_elapsed = jiffies - tg->slice_start[rw]; |
|
|
|
/* Round up to the next throttle slice, wait time must be nonzero */ |
|
jiffy_elapsed_rnd = roundup(jiffy_elapsed + 1, tg->td->throtl_slice); |
|
|
|
/* |
|
* jiffy_elapsed_rnd should not be a big value as minimum iops can be |
|
* 1 then at max jiffy elapsed should be equivalent of 1 second as we |
|
* will allow dispatch after 1 second and after that slice should |
|
* have been trimmed. |
|
*/ |
|
|
|
tmp = (u64)iops_limit * jiffy_elapsed_rnd; |
|
do_div(tmp, HZ); |
|
|
|
if (tmp > UINT_MAX) |
|
io_allowed = UINT_MAX; |
|
else |
|
io_allowed = tmp; |
|
|
|
if (tg->io_disp[rw] + 1 <= io_allowed) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
/* Calc approx time to dispatch */ |
|
jiffy_wait = jiffy_elapsed_rnd - jiffy_elapsed; |
|
|
|
if (wait) |
|
*wait = jiffy_wait; |
|
return false; |
|
} |
|
|
|
static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
|
u64 bps_limit, unsigned long *wait) |
|
{ |
|
bool rw = bio_data_dir(bio); |
|
u64 bytes_allowed, extra_bytes, tmp; |
|
unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
|
unsigned int bio_size = throtl_bio_data_size(bio); |
|
|
|
if (bps_limit == U64_MAX) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
|
|
|
/* Slice has just started. Consider one slice interval */ |
|
if (!jiffy_elapsed) |
|
jiffy_elapsed_rnd = tg->td->throtl_slice; |
|
|
|
jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
|
|
|
tmp = bps_limit * jiffy_elapsed_rnd; |
|
do_div(tmp, HZ); |
|
bytes_allowed = tmp; |
|
|
|
if (tg->bytes_disp[rw] + bio_size <= bytes_allowed) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
/* Calc approx time to dispatch */ |
|
extra_bytes = tg->bytes_disp[rw] + bio_size - bytes_allowed; |
|
jiffy_wait = div64_u64(extra_bytes * HZ, bps_limit); |
|
|
|
if (!jiffy_wait) |
|
jiffy_wait = 1; |
|
|
|
/* |
|
* This wait time is without taking into consideration the rounding |
|
* up we did. Add that time also. |
|
*/ |
|
jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); |
|
if (wait) |
|
*wait = jiffy_wait; |
|
return false; |
|
} |
|
|
|
/* |
|
* Returns whether one can dispatch a bio or not. Also returns approx number |
|
* of jiffies to wait before this bio is with-in IO rate and can be dispatched |
|
*/ |
|
static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
|
unsigned long *wait) |
|
{ |
|
bool rw = bio_data_dir(bio); |
|
unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; |
|
u64 bps_limit = tg_bps_limit(tg, rw); |
|
u32 iops_limit = tg_iops_limit(tg, rw); |
|
|
|
/* |
|
* Currently whole state machine of group depends on first bio |
|
* queued in the group bio list. So one should not be calling |
|
* this function with a different bio if there are other bios |
|
* queued. |
|
*/ |
|
BUG_ON(tg->service_queue.nr_queued[rw] && |
|
bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
|
|
|
/* If tg->bps = -1, then BW is unlimited */ |
|
if (bps_limit == U64_MAX && iops_limit == UINT_MAX) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
/* |
|
* If previous slice expired, start a new one otherwise renew/extend |
|
* existing slice to make sure it is at least throtl_slice interval |
|
* long since now. New slice is started only for empty throttle group. |
|
* If there is queued bio, that means there should be an active |
|
* slice and it should be extended instead. |
|
*/ |
|
if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
|
throtl_start_new_slice(tg, rw); |
|
else { |
|
if (time_before(tg->slice_end[rw], |
|
jiffies + tg->td->throtl_slice)) |
|
throtl_extend_slice(tg, rw, |
|
jiffies + tg->td->throtl_slice); |
|
} |
|
|
|
if (iops_limit != UINT_MAX) |
|
tg->io_disp[rw] += atomic_xchg(&tg->io_split_cnt[rw], 0); |
|
|
|
if (tg_with_in_bps_limit(tg, bio, bps_limit, &bps_wait) && |
|
tg_with_in_iops_limit(tg, bio, iops_limit, &iops_wait)) { |
|
if (wait) |
|
*wait = 0; |
|
return true; |
|
} |
|
|
|
max_wait = max(bps_wait, iops_wait); |
|
|
|
if (wait) |
|
*wait = max_wait; |
|
|
|
if (time_before(tg->slice_end[rw], jiffies + max_wait)) |
|
throtl_extend_slice(tg, rw, jiffies + max_wait); |
|
|
|
return false; |
|
} |
|
|
|
static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) |
|
{ |
|
bool rw = bio_data_dir(bio); |
|
unsigned int bio_size = throtl_bio_data_size(bio); |
|
|
|
/* Charge the bio to the group */ |
|
tg->bytes_disp[rw] += bio_size; |
|
tg->io_disp[rw]++; |
|
tg->last_bytes_disp[rw] += bio_size; |
|
tg->last_io_disp[rw]++; |
|
|
|
/* |
|
* BIO_THROTTLED is used to prevent the same bio to be throttled |
|
* more than once as a throttled bio will go through blk-throtl the |
|
* second time when it eventually gets issued. Set it when a bio |
|
* is being charged to a tg. |
|
*/ |
|
if (!bio_flagged(bio, BIO_THROTTLED)) |
|
bio_set_flag(bio, BIO_THROTTLED); |
|
} |
|
|
|
/** |
|
* throtl_add_bio_tg - add a bio to the specified throtl_grp |
|
* @bio: bio to add |
|
* @qn: qnode to use |
|
* @tg: the target throtl_grp |
|
* |
|
* Add @bio to @tg's service_queue using @qn. If @qn is not specified, |
|
* tg->qnode_on_self[] is used. |
|
*/ |
|
static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, |
|
struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
bool rw = bio_data_dir(bio); |
|
|
|
if (!qn) |
|
qn = &tg->qnode_on_self[rw]; |
|
|
|
/* |
|
* If @tg doesn't currently have any bios queued in the same |
|
* direction, queueing @bio can change when @tg should be |
|
* dispatched. Mark that @tg was empty. This is automatically |
|
* cleared on the next tg_update_disptime(). |
|
*/ |
|
if (!sq->nr_queued[rw]) |
|
tg->flags |= THROTL_TG_WAS_EMPTY; |
|
|
|
throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
|
|
|
sq->nr_queued[rw]++; |
|
throtl_enqueue_tg(tg); |
|
} |
|
|
|
static void tg_update_disptime(struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
|
struct bio *bio; |
|
|
|
bio = throtl_peek_queued(&sq->queued[READ]); |
|
if (bio) |
|
tg_may_dispatch(tg, bio, &read_wait); |
|
|
|
bio = throtl_peek_queued(&sq->queued[WRITE]); |
|
if (bio) |
|
tg_may_dispatch(tg, bio, &write_wait); |
|
|
|
min_wait = min(read_wait, write_wait); |
|
disptime = jiffies + min_wait; |
|
|
|
/* Update dispatch time */ |
|
throtl_dequeue_tg(tg); |
|
tg->disptime = disptime; |
|
throtl_enqueue_tg(tg); |
|
|
|
/* see throtl_add_bio_tg() */ |
|
tg->flags &= ~THROTL_TG_WAS_EMPTY; |
|
} |
|
|
|
static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
|
struct throtl_grp *parent_tg, bool rw) |
|
{ |
|
if (throtl_slice_used(parent_tg, rw)) { |
|
throtl_start_new_slice_with_credit(parent_tg, rw, |
|
child_tg->slice_start[rw]); |
|
} |
|
|
|
} |
|
|
|
static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
struct throtl_service_queue *parent_sq = sq->parent_sq; |
|
struct throtl_grp *parent_tg = sq_to_tg(parent_sq); |
|
struct throtl_grp *tg_to_put = NULL; |
|
struct bio *bio; |
|
|
|
/* |
|
* @bio is being transferred from @tg to @parent_sq. Popping a bio |
|
* from @tg may put its reference and @parent_sq might end up |
|
* getting released prematurely. Remember the tg to put and put it |
|
* after @bio is transferred to @parent_sq. |
|
*/ |
|
bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); |
|
sq->nr_queued[rw]--; |
|
|
|
throtl_charge_bio(tg, bio); |
|
|
|
/* |
|
* If our parent is another tg, we just need to transfer @bio to |
|
* the parent using throtl_add_bio_tg(). If our parent is |
|
* @td->service_queue, @bio is ready to be issued. Put it on its |
|
* bio_lists[] and decrease total number queued. The caller is |
|
* responsible for issuing these bios. |
|
*/ |
|
if (parent_tg) { |
|
throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
|
start_parent_slice_with_credit(tg, parent_tg, rw); |
|
} else { |
|
throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
|
&parent_sq->queued[rw]); |
|
BUG_ON(tg->td->nr_queued[rw] <= 0); |
|
tg->td->nr_queued[rw]--; |
|
} |
|
|
|
throtl_trim_slice(tg, rw); |
|
|
|
if (tg_to_put) |
|
blkg_put(tg_to_blkg(tg_to_put)); |
|
} |
|
|
|
static int throtl_dispatch_tg(struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
unsigned int nr_reads = 0, nr_writes = 0; |
|
unsigned int max_nr_reads = THROTL_GRP_QUANTUM * 3 / 4; |
|
unsigned int max_nr_writes = THROTL_GRP_QUANTUM - max_nr_reads; |
|
struct bio *bio; |
|
|
|
/* Try to dispatch 75% READS and 25% WRITES */ |
|
|
|
while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
|
tg_may_dispatch(tg, bio, NULL)) { |
|
|
|
tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
|
nr_reads++; |
|
|
|
if (nr_reads >= max_nr_reads) |
|
break; |
|
} |
|
|
|
while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
|
tg_may_dispatch(tg, bio, NULL)) { |
|
|
|
tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
|
nr_writes++; |
|
|
|
if (nr_writes >= max_nr_writes) |
|
break; |
|
} |
|
|
|
return nr_reads + nr_writes; |
|
} |
|
|
|
static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
|
{ |
|
unsigned int nr_disp = 0; |
|
|
|
while (1) { |
|
struct throtl_grp *tg; |
|
struct throtl_service_queue *sq; |
|
|
|
if (!parent_sq->nr_pending) |
|
break; |
|
|
|
tg = throtl_rb_first(parent_sq); |
|
if (!tg) |
|
break; |
|
|
|
if (time_before(jiffies, tg->disptime)) |
|
break; |
|
|
|
throtl_dequeue_tg(tg); |
|
|
|
nr_disp += throtl_dispatch_tg(tg); |
|
|
|
sq = &tg->service_queue; |
|
if (sq->nr_queued[0] || sq->nr_queued[1]) |
|
tg_update_disptime(tg); |
|
|
|
if (nr_disp >= THROTL_QUANTUM) |
|
break; |
|
} |
|
|
|
return nr_disp; |
|
} |
|
|
|
static bool throtl_can_upgrade(struct throtl_data *td, |
|
struct throtl_grp *this_tg); |
|
/** |
|
* throtl_pending_timer_fn - timer function for service_queue->pending_timer |
|
* @t: the pending_timer member of the throtl_service_queue being serviced |
|
* |
|
* This timer is armed when a child throtl_grp with active bio's become |
|
* pending and queued on the service_queue's pending_tree and expires when |
|
* the first child throtl_grp should be dispatched. This function |
|
* dispatches bio's from the children throtl_grps to the parent |
|
* service_queue. |
|
* |
|
* If the parent's parent is another throtl_grp, dispatching is propagated |
|
* by either arming its pending_timer or repeating dispatch directly. If |
|
* the top-level service_tree is reached, throtl_data->dispatch_work is |
|
* kicked so that the ready bio's are issued. |
|
*/ |
|
static void throtl_pending_timer_fn(struct timer_list *t) |
|
{ |
|
struct throtl_service_queue *sq = from_timer(sq, t, pending_timer); |
|
struct throtl_grp *tg = sq_to_tg(sq); |
|
struct throtl_data *td = sq_to_td(sq); |
|
struct request_queue *q = td->queue; |
|
struct throtl_service_queue *parent_sq; |
|
bool dispatched; |
|
int ret; |
|
|
|
spin_lock_irq(&q->queue_lock); |
|
if (throtl_can_upgrade(td, NULL)) |
|
throtl_upgrade_state(td); |
|
|
|
again: |
|
parent_sq = sq->parent_sq; |
|
dispatched = false; |
|
|
|
while (true) { |
|
throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", |
|
sq->nr_queued[READ] + sq->nr_queued[WRITE], |
|
sq->nr_queued[READ], sq->nr_queued[WRITE]); |
|
|
|
ret = throtl_select_dispatch(sq); |
|
if (ret) { |
|
throtl_log(sq, "bios disp=%u", ret); |
|
dispatched = true; |
|
} |
|
|
|
if (throtl_schedule_next_dispatch(sq, false)) |
|
break; |
|
|
|
/* this dispatch windows is still open, relax and repeat */ |
|
spin_unlock_irq(&q->queue_lock); |
|
cpu_relax(); |
|
spin_lock_irq(&q->queue_lock); |
|
} |
|
|
|
if (!dispatched) |
|
goto out_unlock; |
|
|
|
if (parent_sq) { |
|
/* @parent_sq is another throl_grp, propagate dispatch */ |
|
if (tg->flags & THROTL_TG_WAS_EMPTY) { |
|
tg_update_disptime(tg); |
|
if (!throtl_schedule_next_dispatch(parent_sq, false)) { |
|
/* window is already open, repeat dispatching */ |
|
sq = parent_sq; |
|
tg = sq_to_tg(sq); |
|
goto again; |
|
} |
|
} |
|
} else { |
|
/* reached the top-level, queue issuing */ |
|
queue_work(kthrotld_workqueue, &td->dispatch_work); |
|
} |
|
out_unlock: |
|
spin_unlock_irq(&q->queue_lock); |
|
} |
|
|
|
/** |
|
* blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work |
|
* @work: work item being executed |
|
* |
|
* This function is queued for execution when bios reach the bio_lists[] |
|
* of throtl_data->service_queue. Those bios are ready and issued by this |
|
* function. |
|
*/ |
|
static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
|
{ |
|
struct throtl_data *td = container_of(work, struct throtl_data, |
|
dispatch_work); |
|
struct throtl_service_queue *td_sq = &td->service_queue; |
|
struct request_queue *q = td->queue; |
|
struct bio_list bio_list_on_stack; |
|
struct bio *bio; |
|
struct blk_plug plug; |
|
int rw; |
|
|
|
bio_list_init(&bio_list_on_stack); |
|
|
|
spin_lock_irq(&q->queue_lock); |
|
for (rw = READ; rw <= WRITE; rw++) |
|
while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) |
|
bio_list_add(&bio_list_on_stack, bio); |
|
spin_unlock_irq(&q->queue_lock); |
|
|
|
if (!bio_list_empty(&bio_list_on_stack)) { |
|
blk_start_plug(&plug); |
|
while ((bio = bio_list_pop(&bio_list_on_stack))) |
|
submit_bio_noacct(bio); |
|
blk_finish_plug(&plug); |
|
} |
|
} |
|
|
|
static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
|
int off) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
u64 v = *(u64 *)((void *)tg + off); |
|
|
|
if (v == U64_MAX) |
|
return 0; |
|
return __blkg_prfill_u64(sf, pd, v); |
|
} |
|
|
|
static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
|
int off) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
unsigned int v = *(unsigned int *)((void *)tg + off); |
|
|
|
if (v == UINT_MAX) |
|
return 0; |
|
return __blkg_prfill_u64(sf, pd, v); |
|
} |
|
|
|
static int tg_print_conf_u64(struct seq_file *sf, void *v) |
|
{ |
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
|
&blkcg_policy_throtl, seq_cft(sf)->private, false); |
|
return 0; |
|
} |
|
|
|
static int tg_print_conf_uint(struct seq_file *sf, void *v) |
|
{ |
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
|
&blkcg_policy_throtl, seq_cft(sf)->private, false); |
|
return 0; |
|
} |
|
|
|
static void tg_conf_updated(struct throtl_grp *tg, bool global) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
struct cgroup_subsys_state *pos_css; |
|
struct blkcg_gq *blkg; |
|
|
|
throtl_log(&tg->service_queue, |
|
"limit change rbps=%llu wbps=%llu riops=%u wiops=%u", |
|
tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
|
tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); |
|
|
|
/* |
|
* Update has_rules[] flags for the updated tg's subtree. A tg is |
|
* considered to have rules if either the tg itself or any of its |
|
* ancestors has rules. This identifies groups without any |
|
* restrictions in the whole hierarchy and allows them to bypass |
|
* blk-throttle. |
|
*/ |
|
blkg_for_each_descendant_pre(blkg, pos_css, |
|
global ? tg->td->queue->root_blkg : tg_to_blkg(tg)) { |
|
struct throtl_grp *this_tg = blkg_to_tg(blkg); |
|
struct throtl_grp *parent_tg; |
|
|
|
tg_update_has_rules(this_tg); |
|
/* ignore root/second level */ |
|
if (!cgroup_subsys_on_dfl(io_cgrp_subsys) || !blkg->parent || |
|
!blkg->parent->parent) |
|
continue; |
|
parent_tg = blkg_to_tg(blkg->parent); |
|
/* |
|
* make sure all children has lower idle time threshold and |
|
* higher latency target |
|
*/ |
|
this_tg->idletime_threshold = min(this_tg->idletime_threshold, |
|
parent_tg->idletime_threshold); |
|
this_tg->latency_target = max(this_tg->latency_target, |
|
parent_tg->latency_target); |
|
} |
|
|
|
/* |
|
* We're already holding queue_lock and know @tg is valid. Let's |
|
* apply the new config directly. |
|
* |
|
* Restart the slices for both READ and WRITES. It might happen |
|
* that a group's limit are dropped suddenly and we don't want to |
|
* account recently dispatched IO with new low rate. |
|
*/ |
|
throtl_start_new_slice(tg, READ); |
|
throtl_start_new_slice(tg, WRITE); |
|
|
|
if (tg->flags & THROTL_TG_PENDING) { |
|
tg_update_disptime(tg); |
|
throtl_schedule_next_dispatch(sq->parent_sq, true); |
|
} |
|
} |
|
|
|
static ssize_t tg_set_conf(struct kernfs_open_file *of, |
|
char *buf, size_t nbytes, loff_t off, bool is_u64) |
|
{ |
|
struct blkcg *blkcg = css_to_blkcg(of_css(of)); |
|
struct blkg_conf_ctx ctx; |
|
struct throtl_grp *tg; |
|
int ret; |
|
u64 v; |
|
|
|
ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); |
|
if (ret) |
|
return ret; |
|
|
|
ret = -EINVAL; |
|
if (sscanf(ctx.body, "%llu", &v) != 1) |
|
goto out_finish; |
|
if (!v) |
|
v = U64_MAX; |
|
|
|
tg = blkg_to_tg(ctx.blkg); |
|
|
|
if (is_u64) |
|
*(u64 *)((void *)tg + of_cft(of)->private) = v; |
|
else |
|
*(unsigned int *)((void *)tg + of_cft(of)->private) = v; |
|
|
|
tg_conf_updated(tg, false); |
|
ret = 0; |
|
out_finish: |
|
blkg_conf_finish(&ctx); |
|
return ret ?: nbytes; |
|
} |
|
|
|
static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
|
char *buf, size_t nbytes, loff_t off) |
|
{ |
|
return tg_set_conf(of, buf, nbytes, off, true); |
|
} |
|
|
|
static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
|
char *buf, size_t nbytes, loff_t off) |
|
{ |
|
return tg_set_conf(of, buf, nbytes, off, false); |
|
} |
|
|
|
static int tg_print_rwstat(struct seq_file *sf, void *v) |
|
{ |
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), |
|
blkg_prfill_rwstat, &blkcg_policy_throtl, |
|
seq_cft(sf)->private, true); |
|
return 0; |
|
} |
|
|
|
static u64 tg_prfill_rwstat_recursive(struct seq_file *sf, |
|
struct blkg_policy_data *pd, int off) |
|
{ |
|
struct blkg_rwstat_sample sum; |
|
|
|
blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_throtl, off, |
|
&sum); |
|
return __blkg_prfill_rwstat(sf, pd, &sum); |
|
} |
|
|
|
static int tg_print_rwstat_recursive(struct seq_file *sf, void *v) |
|
{ |
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), |
|
tg_prfill_rwstat_recursive, &blkcg_policy_throtl, |
|
seq_cft(sf)->private, true); |
|
return 0; |
|
} |
|
|
|
static struct cftype throtl_legacy_files[] = { |
|
{ |
|
.name = "throttle.read_bps_device", |
|
.private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
|
.seq_show = tg_print_conf_u64, |
|
.write = tg_set_conf_u64, |
|
}, |
|
{ |
|
.name = "throttle.write_bps_device", |
|
.private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
|
.seq_show = tg_print_conf_u64, |
|
.write = tg_set_conf_u64, |
|
}, |
|
{ |
|
.name = "throttle.read_iops_device", |
|
.private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
|
.seq_show = tg_print_conf_uint, |
|
.write = tg_set_conf_uint, |
|
}, |
|
{ |
|
.name = "throttle.write_iops_device", |
|
.private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
|
.seq_show = tg_print_conf_uint, |
|
.write = tg_set_conf_uint, |
|
}, |
|
{ |
|
.name = "throttle.io_service_bytes", |
|
.private = offsetof(struct throtl_grp, stat_bytes), |
|
.seq_show = tg_print_rwstat, |
|
}, |
|
{ |
|
.name = "throttle.io_service_bytes_recursive", |
|
.private = offsetof(struct throtl_grp, stat_bytes), |
|
.seq_show = tg_print_rwstat_recursive, |
|
}, |
|
{ |
|
.name = "throttle.io_serviced", |
|
.private = offsetof(struct throtl_grp, stat_ios), |
|
.seq_show = tg_print_rwstat, |
|
}, |
|
{ |
|
.name = "throttle.io_serviced_recursive", |
|
.private = offsetof(struct throtl_grp, stat_ios), |
|
.seq_show = tg_print_rwstat_recursive, |
|
}, |
|
{ } /* terminate */ |
|
}; |
|
|
|
static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
|
int off) |
|
{ |
|
struct throtl_grp *tg = pd_to_tg(pd); |
|
const char *dname = blkg_dev_name(pd->blkg); |
|
char bufs[4][21] = { "max", "max", "max", "max" }; |
|
u64 bps_dft; |
|
unsigned int iops_dft; |
|
char idle_time[26] = ""; |
|
char latency_time[26] = ""; |
|
|
|
if (!dname) |
|
return 0; |
|
|
|
if (off == LIMIT_LOW) { |
|
bps_dft = 0; |
|
iops_dft = 0; |
|
} else { |
|
bps_dft = U64_MAX; |
|
iops_dft = UINT_MAX; |
|
} |
|
|
|
if (tg->bps_conf[READ][off] == bps_dft && |
|
tg->bps_conf[WRITE][off] == bps_dft && |
|
tg->iops_conf[READ][off] == iops_dft && |
|
tg->iops_conf[WRITE][off] == iops_dft && |
|
(off != LIMIT_LOW || |
|
(tg->idletime_threshold_conf == DFL_IDLE_THRESHOLD && |
|
tg->latency_target_conf == DFL_LATENCY_TARGET))) |
|
return 0; |
|
|
|
if (tg->bps_conf[READ][off] != U64_MAX) |
|
snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
|
tg->bps_conf[READ][off]); |
|
if (tg->bps_conf[WRITE][off] != U64_MAX) |
|
snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
|
tg->bps_conf[WRITE][off]); |
|
if (tg->iops_conf[READ][off] != UINT_MAX) |
|
snprintf(bufs[2], sizeof(bufs[2]), "%u", |
|
tg->iops_conf[READ][off]); |
|
if (tg->iops_conf[WRITE][off] != UINT_MAX) |
|
snprintf(bufs[3], sizeof(bufs[3]), "%u", |
|
tg->iops_conf[WRITE][off]); |
|
if (off == LIMIT_LOW) { |
|
if (tg->idletime_threshold_conf == ULONG_MAX) |
|
strcpy(idle_time, " idle=max"); |
|
else |
|
snprintf(idle_time, sizeof(idle_time), " idle=%lu", |
|
tg->idletime_threshold_conf); |
|
|
|
if (tg->latency_target_conf == ULONG_MAX) |
|
strcpy(latency_time, " latency=max"); |
|
else |
|
snprintf(latency_time, sizeof(latency_time), |
|
" latency=%lu", tg->latency_target_conf); |
|
} |
|
|
|
seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s%s%s\n", |
|
dname, bufs[0], bufs[1], bufs[2], bufs[3], idle_time, |
|
latency_time); |
|
return 0; |
|
} |
|
|
|
static int tg_print_limit(struct seq_file *sf, void *v) |
|
{ |
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
|
&blkcg_policy_throtl, seq_cft(sf)->private, false); |
|
return 0; |
|
} |
|
|
|
static ssize_t tg_set_limit(struct kernfs_open_file *of, |
|
char *buf, size_t nbytes, loff_t off) |
|
{ |
|
struct blkcg *blkcg = css_to_blkcg(of_css(of)); |
|
struct blkg_conf_ctx ctx; |
|
struct throtl_grp *tg; |
|
u64 v[4]; |
|
unsigned long idle_time; |
|
unsigned long latency_time; |
|
int ret; |
|
int index = of_cft(of)->private; |
|
|
|
ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); |
|
if (ret) |
|
return ret; |
|
|
|
tg = blkg_to_tg(ctx.blkg); |
|
|
|
v[0] = tg->bps_conf[READ][index]; |
|
v[1] = tg->bps_conf[WRITE][index]; |
|
v[2] = tg->iops_conf[READ][index]; |
|
v[3] = tg->iops_conf[WRITE][index]; |
|
|
|
idle_time = tg->idletime_threshold_conf; |
|
latency_time = tg->latency_target_conf; |
|
while (true) { |
|
char tok[27]; /* wiops=18446744073709551616 */ |
|
char *p; |
|
u64 val = U64_MAX; |
|
int len; |
|
|
|
if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) |
|
break; |
|
if (tok[0] == '\0') |
|
break; |
|
ctx.body += len; |
|
|
|
ret = -EINVAL; |
|
p = tok; |
|
strsep(&p, "="); |
|
if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) |
|
goto out_finish; |
|
|
|
ret = -ERANGE; |
|
if (!val) |
|
goto out_finish; |
|
|
|
ret = -EINVAL; |
|
if (!strcmp(tok, "rbps") && val > 1) |
|
v[0] = val; |
|
else if (!strcmp(tok, "wbps") && val > 1) |
|
v[1] = val; |
|
else if (!strcmp(tok, "riops") && val > 1) |
|
v[2] = min_t(u64, val, UINT_MAX); |
|
else if (!strcmp(tok, "wiops") && val > 1) |
|
v[3] = min_t(u64, val, UINT_MAX); |
|
else if (off == LIMIT_LOW && !strcmp(tok, "idle")) |
|
idle_time = val; |
|
else if (off == LIMIT_LOW && !strcmp(tok, "latency")) |
|
latency_time = val; |
|
else |
|
goto out_finish; |
|
} |
|
|
|
tg->bps_conf[READ][index] = v[0]; |
|
tg->bps_conf[WRITE][index] = v[1]; |
|
tg->iops_conf[READ][index] = v[2]; |
|
tg->iops_conf[WRITE][index] = v[3]; |
|
|
|
if (index == LIMIT_MAX) { |
|
tg->bps[READ][index] = v[0]; |
|
tg->bps[WRITE][index] = v[1]; |
|
tg->iops[READ][index] = v[2]; |
|
tg->iops[WRITE][index] = v[3]; |
|
} |
|
tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], |
|
tg->bps_conf[READ][LIMIT_MAX]); |
|
tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], |
|
tg->bps_conf[WRITE][LIMIT_MAX]); |
|
tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], |
|
tg->iops_conf[READ][LIMIT_MAX]); |
|
tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], |
|
tg->iops_conf[WRITE][LIMIT_MAX]); |
|
tg->idletime_threshold_conf = idle_time; |
|
tg->latency_target_conf = latency_time; |
|
|
|
/* force user to configure all settings for low limit */ |
|
if (!(tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW] || |
|
tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) || |
|
tg->idletime_threshold_conf == DFL_IDLE_THRESHOLD || |
|
tg->latency_target_conf == DFL_LATENCY_TARGET) { |
|
tg->bps[READ][LIMIT_LOW] = 0; |
|
tg->bps[WRITE][LIMIT_LOW] = 0; |
|
tg->iops[READ][LIMIT_LOW] = 0; |
|
tg->iops[WRITE][LIMIT_LOW] = 0; |
|
tg->idletime_threshold = DFL_IDLE_THRESHOLD; |
|
tg->latency_target = DFL_LATENCY_TARGET; |
|
} else if (index == LIMIT_LOW) { |
|
tg->idletime_threshold = tg->idletime_threshold_conf; |
|
tg->latency_target = tg->latency_target_conf; |
|
} |
|
|
|
blk_throtl_update_limit_valid(tg->td); |
|
if (tg->td->limit_valid[LIMIT_LOW]) { |
|
if (index == LIMIT_LOW) |
|
tg->td->limit_index = LIMIT_LOW; |
|
} else |
|
tg->td->limit_index = LIMIT_MAX; |
|
tg_conf_updated(tg, index == LIMIT_LOW && |
|
tg->td->limit_valid[LIMIT_LOW]); |
|
ret = 0; |
|
out_finish: |
|
blkg_conf_finish(&ctx); |
|
return ret ?: nbytes; |
|
} |
|
|
|
static struct cftype throtl_files[] = { |
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
{ |
|
.name = "low", |
|
.flags = CFTYPE_NOT_ON_ROOT, |
|
.seq_show = tg_print_limit, |
|
.write = tg_set_limit, |
|
.private = LIMIT_LOW, |
|
}, |
|
#endif |
|
{ |
|
.name = "max", |
|
.flags = CFTYPE_NOT_ON_ROOT, |
|
.seq_show = tg_print_limit, |
|
.write = tg_set_limit, |
|
.private = LIMIT_MAX, |
|
}, |
|
{ } /* terminate */ |
|
}; |
|
|
|
static void throtl_shutdown_wq(struct request_queue *q) |
|
{ |
|
struct throtl_data *td = q->td; |
|
|
|
cancel_work_sync(&td->dispatch_work); |
|
} |
|
|
|
static struct blkcg_policy blkcg_policy_throtl = { |
|
.dfl_cftypes = throtl_files, |
|
.legacy_cftypes = throtl_legacy_files, |
|
|
|
.pd_alloc_fn = throtl_pd_alloc, |
|
.pd_init_fn = throtl_pd_init, |
|
.pd_online_fn = throtl_pd_online, |
|
.pd_offline_fn = throtl_pd_offline, |
|
.pd_free_fn = throtl_pd_free, |
|
}; |
|
|
|
static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
|
{ |
|
unsigned long rtime = jiffies, wtime = jiffies; |
|
|
|
if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) |
|
rtime = tg->last_low_overflow_time[READ]; |
|
if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) |
|
wtime = tg->last_low_overflow_time[WRITE]; |
|
return min(rtime, wtime); |
|
} |
|
|
|
/* tg should not be an intermediate node */ |
|
static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *parent_sq; |
|
struct throtl_grp *parent = tg; |
|
unsigned long ret = __tg_last_low_overflow_time(tg); |
|
|
|
while (true) { |
|
parent_sq = parent->service_queue.parent_sq; |
|
parent = sq_to_tg(parent_sq); |
|
if (!parent) |
|
break; |
|
|
|
/* |
|
* The parent doesn't have low limit, it always reaches low |
|
* limit. Its overflow time is useless for children |
|
*/ |
|
if (!parent->bps[READ][LIMIT_LOW] && |
|
!parent->iops[READ][LIMIT_LOW] && |
|
!parent->bps[WRITE][LIMIT_LOW] && |
|
!parent->iops[WRITE][LIMIT_LOW]) |
|
continue; |
|
if (time_after(__tg_last_low_overflow_time(parent), ret)) |
|
ret = __tg_last_low_overflow_time(parent); |
|
} |
|
return ret; |
|
} |
|
|
|
static bool throtl_tg_is_idle(struct throtl_grp *tg) |
|
{ |
|
/* |
|
* cgroup is idle if: |
|
* - single idle is too long, longer than a fixed value (in case user |
|
* configure a too big threshold) or 4 times of idletime threshold |
|
* - average think time is more than threshold |
|
* - IO latency is largely below threshold |
|
*/ |
|
unsigned long time; |
|
bool ret; |
|
|
|
time = min_t(unsigned long, MAX_IDLE_TIME, 4 * tg->idletime_threshold); |
|
ret = tg->latency_target == DFL_LATENCY_TARGET || |
|
tg->idletime_threshold == DFL_IDLE_THRESHOLD || |
|
(ktime_get_ns() >> 10) - tg->last_finish_time > time || |
|
tg->avg_idletime > tg->idletime_threshold || |
|
(tg->latency_target && tg->bio_cnt && |
|
tg->bad_bio_cnt * 5 < tg->bio_cnt); |
|
throtl_log(&tg->service_queue, |
|
"avg_idle=%ld, idle_threshold=%ld, bad_bio=%d, total_bio=%d, is_idle=%d, scale=%d", |
|
tg->avg_idletime, tg->idletime_threshold, tg->bad_bio_cnt, |
|
tg->bio_cnt, ret, tg->td->scale); |
|
return ret; |
|
} |
|
|
|
static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
|
{ |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
bool read_limit, write_limit; |
|
|
|
/* |
|
* if cgroup reaches low limit (if low limit is 0, the cgroup always |
|
* reaches), it's ok to upgrade to next limit |
|
*/ |
|
read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; |
|
write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; |
|
if (!read_limit && !write_limit) |
|
return true; |
|
if (read_limit && sq->nr_queued[READ] && |
|
(!write_limit || sq->nr_queued[WRITE])) |
|
return true; |
|
if (write_limit && sq->nr_queued[WRITE] && |
|
(!read_limit || sq->nr_queued[READ])) |
|
return true; |
|
|
|
if (time_after_eq(jiffies, |
|
tg_last_low_overflow_time(tg) + tg->td->throtl_slice) && |
|
throtl_tg_is_idle(tg)) |
|
return true; |
|
return false; |
|
} |
|
|
|
static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) |
|
{ |
|
while (true) { |
|
if (throtl_tg_can_upgrade(tg)) |
|
return true; |
|
tg = sq_to_tg(tg->service_queue.parent_sq); |
|
if (!tg || !tg_to_blkg(tg)->parent) |
|
return false; |
|
} |
|
return false; |
|
} |
|
|
|
static bool throtl_can_upgrade(struct throtl_data *td, |
|
struct throtl_grp *this_tg) |
|
{ |
|
struct cgroup_subsys_state *pos_css; |
|
struct blkcg_gq *blkg; |
|
|
|
if (td->limit_index != LIMIT_LOW) |
|
return false; |
|
|
|
if (time_before(jiffies, td->low_downgrade_time + td->throtl_slice)) |
|
return false; |
|
|
|
rcu_read_lock(); |
|
blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { |
|
struct throtl_grp *tg = blkg_to_tg(blkg); |
|
|
|
if (tg == this_tg) |
|
continue; |
|
if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) |
|
continue; |
|
if (!throtl_hierarchy_can_upgrade(tg)) { |
|
rcu_read_unlock(); |
|
return false; |
|
} |
|
} |
|
rcu_read_unlock(); |
|
return true; |
|
} |
|
|
|
static void throtl_upgrade_check(struct throtl_grp *tg) |
|
{ |
|
unsigned long now = jiffies; |
|
|
|
if (tg->td->limit_index != LIMIT_LOW) |
|
return; |
|
|
|
if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
|
return; |
|
|
|
tg->last_check_time = now; |
|
|
|
if (!time_after_eq(now, |
|
__tg_last_low_overflow_time(tg) + tg->td->throtl_slice)) |
|
return; |
|
|
|
if (throtl_can_upgrade(tg->td, NULL)) |
|
throtl_upgrade_state(tg->td); |
|
} |
|
|
|
static void throtl_upgrade_state(struct throtl_data *td) |
|
{ |
|
struct cgroup_subsys_state *pos_css; |
|
struct blkcg_gq *blkg; |
|
|
|
throtl_log(&td->service_queue, "upgrade to max"); |
|
td->limit_index = LIMIT_MAX; |
|
td->low_upgrade_time = jiffies; |
|
td->scale = 0; |
|
rcu_read_lock(); |
|
blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { |
|
struct throtl_grp *tg = blkg_to_tg(blkg); |
|
struct throtl_service_queue *sq = &tg->service_queue; |
|
|
|
tg->disptime = jiffies - 1; |
|
throtl_select_dispatch(sq); |
|
throtl_schedule_next_dispatch(sq, true); |
|
} |
|
rcu_read_unlock(); |
|
throtl_select_dispatch(&td->service_queue); |
|
throtl_schedule_next_dispatch(&td->service_queue, true); |
|
queue_work(kthrotld_workqueue, &td->dispatch_work); |
|
} |
|
|
|
static void throtl_downgrade_state(struct throtl_data *td) |
|
{ |
|
td->scale /= 2; |
|
|
|
throtl_log(&td->service_queue, "downgrade, scale %d", td->scale); |
|
if (td->scale) { |
|
td->low_upgrade_time = jiffies - td->scale * td->throtl_slice; |
|
return; |
|
} |
|
|
|
td->limit_index = LIMIT_LOW; |
|
td->low_downgrade_time = jiffies; |
|
} |
|
|
|
static bool throtl_tg_can_downgrade(struct throtl_grp *tg) |
|
{ |
|
struct throtl_data *td = tg->td; |
|
unsigned long now = jiffies; |
|
|
|
/* |
|
* If cgroup is below low limit, consider downgrade and throttle other |
|
* cgroups |
|
*/ |
|
if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && |
|
time_after_eq(now, tg_last_low_overflow_time(tg) + |
|
td->throtl_slice) && |
|
(!throtl_tg_is_idle(tg) || |
|
!list_empty(&tg_to_blkg(tg)->blkcg->css.children))) |
|
return true; |
|
return false; |
|
} |
|
|
|
static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) |
|
{ |
|
while (true) { |
|
if (!throtl_tg_can_downgrade(tg)) |
|
return false; |
|
tg = sq_to_tg(tg->service_queue.parent_sq); |
|
if (!tg || !tg_to_blkg(tg)->parent) |
|
break; |
|
} |
|
return true; |
|
} |
|
|
|
static void throtl_downgrade_check(struct throtl_grp *tg) |
|
{ |
|
uint64_t bps; |
|
unsigned int iops; |
|
unsigned long elapsed_time; |
|
unsigned long now = jiffies; |
|
|
|
if (tg->td->limit_index != LIMIT_MAX || |
|
!tg->td->limit_valid[LIMIT_LOW]) |
|
return; |
|
if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) |
|
return; |
|
if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
|
return; |
|
|
|
elapsed_time = now - tg->last_check_time; |
|
tg->last_check_time = now; |
|
|
|
if (time_before(now, tg_last_low_overflow_time(tg) + |
|
tg->td->throtl_slice)) |
|
return; |
|
|
|
if (tg->bps[READ][LIMIT_LOW]) { |
|
bps = tg->last_bytes_disp[READ] * HZ; |
|
do_div(bps, elapsed_time); |
|
if (bps >= tg->bps[READ][LIMIT_LOW]) |
|
tg->last_low_overflow_time[READ] = now; |
|
} |
|
|
|
if (tg->bps[WRITE][LIMIT_LOW]) { |
|
bps = tg->last_bytes_disp[WRITE] * HZ; |
|
do_div(bps, elapsed_time); |
|
if (bps >= tg->bps[WRITE][LIMIT_LOW]) |
|
tg->last_low_overflow_time[WRITE] = now; |
|
} |
|
|
|
if (tg->iops[READ][LIMIT_LOW]) { |
|
tg->last_io_disp[READ] += atomic_xchg(&tg->last_io_split_cnt[READ], 0); |
|
iops = tg->last_io_disp[READ] * HZ / elapsed_time; |
|
if (iops >= tg->iops[READ][LIMIT_LOW]) |
|
tg->last_low_overflow_time[READ] = now; |
|
} |
|
|
|
if (tg->iops[WRITE][LIMIT_LOW]) { |
|
tg->last_io_disp[WRITE] += atomic_xchg(&tg->last_io_split_cnt[WRITE], 0); |
|
iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; |
|
if (iops >= tg->iops[WRITE][LIMIT_LOW]) |
|
tg->last_low_overflow_time[WRITE] = now; |
|
} |
|
|
|
/* |
|
* If cgroup is below low limit, consider downgrade and throttle other |
|
* cgroups |
|
*/ |
|
if (throtl_hierarchy_can_downgrade(tg)) |
|
throtl_downgrade_state(tg->td); |
|
|
|
tg->last_bytes_disp[READ] = 0; |
|
tg->last_bytes_disp[WRITE] = 0; |
|
tg->last_io_disp[READ] = 0; |
|
tg->last_io_disp[WRITE] = 0; |
|
} |
|
|
|
static void blk_throtl_update_idletime(struct throtl_grp *tg) |
|
{ |
|
unsigned long now; |
|
unsigned long last_finish_time = tg->last_finish_time; |
|
|
|
if (last_finish_time == 0) |
|
return; |
|
|
|
now = ktime_get_ns() >> 10; |
|
if (now <= last_finish_time || |
|
last_finish_time == tg->checked_last_finish_time) |
|
return; |
|
|
|
tg->avg_idletime = (tg->avg_idletime * 7 + now - last_finish_time) >> 3; |
|
tg->checked_last_finish_time = last_finish_time; |
|
} |
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
static void throtl_update_latency_buckets(struct throtl_data *td) |
|
{ |
|
struct avg_latency_bucket avg_latency[2][LATENCY_BUCKET_SIZE]; |
|
int i, cpu, rw; |
|
unsigned long last_latency[2] = { 0 }; |
|
unsigned long latency[2]; |
|
|
|
if (!blk_queue_nonrot(td->queue) || !td->limit_valid[LIMIT_LOW]) |
|
return; |
|
if (time_before(jiffies, td->last_calculate_time + HZ)) |
|
return; |
|
td->last_calculate_time = jiffies; |
|
|
|
memset(avg_latency, 0, sizeof(avg_latency)); |
|
for (rw = READ; rw <= WRITE; rw++) { |
|
for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { |
|
struct latency_bucket *tmp = &td->tmp_buckets[rw][i]; |
|
|
|
for_each_possible_cpu(cpu) { |
|
struct latency_bucket *bucket; |
|
|
|
/* this isn't race free, but ok in practice */ |
|
bucket = per_cpu_ptr(td->latency_buckets[rw], |
|
cpu); |
|
tmp->total_latency += bucket[i].total_latency; |
|
tmp->samples += bucket[i].samples; |
|
bucket[i].total_latency = 0; |
|
bucket[i].samples = 0; |
|
} |
|
|
|
if (tmp->samples >= 32) { |
|
int samples = tmp->samples; |
|
|
|
latency[rw] = tmp->total_latency; |
|
|
|
tmp->total_latency = 0; |
|
tmp->samples = 0; |
|
latency[rw] /= samples; |
|
if (latency[rw] == 0) |
|
continue; |
|
avg_latency[rw][i].latency = latency[rw]; |
|
} |
|
} |
|
} |
|
|
|
for (rw = READ; rw <= WRITE; rw++) { |
|
for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { |
|
if (!avg_latency[rw][i].latency) { |
|
if (td->avg_buckets[rw][i].latency < last_latency[rw]) |
|
td->avg_buckets[rw][i].latency = |
|
last_latency[rw]; |
|
continue; |
|
} |
|
|
|
if (!td->avg_buckets[rw][i].valid) |
|
latency[rw] = avg_latency[rw][i].latency; |
|
else |
|
latency[rw] = (td->avg_buckets[rw][i].latency * 7 + |
|
avg_latency[rw][i].latency) >> 3; |
|
|
|
td->avg_buckets[rw][i].latency = max(latency[rw], |
|
last_latency[rw]); |
|
td->avg_buckets[rw][i].valid = true; |
|
last_latency[rw] = td->avg_buckets[rw][i].latency; |
|
} |
|
} |
|
|
|
for (i = 0; i < LATENCY_BUCKET_SIZE; i++) |
|
throtl_log(&td->service_queue, |
|
"Latency bucket %d: read latency=%ld, read valid=%d, " |
|
"write latency=%ld, write valid=%d", i, |
|
td->avg_buckets[READ][i].latency, |
|
td->avg_buckets[READ][i].valid, |
|
td->avg_buckets[WRITE][i].latency, |
|
td->avg_buckets[WRITE][i].valid); |
|
} |
|
#else |
|
static inline void throtl_update_latency_buckets(struct throtl_data *td) |
|
{ |
|
} |
|
#endif |
|
|
|
void blk_throtl_charge_bio_split(struct bio *bio) |
|
{ |
|
struct blkcg_gq *blkg = bio->bi_blkg; |
|
struct throtl_grp *parent = blkg_to_tg(blkg); |
|
struct throtl_service_queue *parent_sq; |
|
bool rw = bio_data_dir(bio); |
|
|
|
do { |
|
if (!parent->has_rules[rw]) |
|
break; |
|
|
|
atomic_inc(&parent->io_split_cnt[rw]); |
|
atomic_inc(&parent->last_io_split_cnt[rw]); |
|
|
|
parent_sq = parent->service_queue.parent_sq; |
|
parent = sq_to_tg(parent_sq); |
|
} while (parent); |
|
} |
|
|
|
bool blk_throtl_bio(struct bio *bio) |
|
{ |
|
struct request_queue *q = bio->bi_bdev->bd_disk->queue; |
|
struct blkcg_gq *blkg = bio->bi_blkg; |
|
struct throtl_qnode *qn = NULL; |
|
struct throtl_grp *tg = blkg_to_tg(blkg); |
|
struct throtl_service_queue *sq; |
|
bool rw = bio_data_dir(bio); |
|
bool throttled = false; |
|
struct throtl_data *td = tg->td; |
|
|
|
rcu_read_lock(); |
|
|
|
/* see throtl_charge_bio() */ |
|
if (bio_flagged(bio, BIO_THROTTLED)) |
|
goto out; |
|
|
|
if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { |
|
blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, |
|
bio->bi_iter.bi_size); |
|
blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); |
|
} |
|
|
|
if (!tg->has_rules[rw]) |
|
goto out; |
|
|
|
spin_lock_irq(&q->queue_lock); |
|
|
|
throtl_update_latency_buckets(td); |
|
|
|
blk_throtl_update_idletime(tg); |
|
|
|
sq = &tg->service_queue; |
|
|
|
again: |
|
while (true) { |
|
if (tg->last_low_overflow_time[rw] == 0) |
|
tg->last_low_overflow_time[rw] = jiffies; |
|
throtl_downgrade_check(tg); |
|
throtl_upgrade_check(tg); |
|
/* throtl is FIFO - if bios are already queued, should queue */ |
|
if (sq->nr_queued[rw]) |
|
break; |
|
|
|
/* if above limits, break to queue */ |
|
if (!tg_may_dispatch(tg, bio, NULL)) { |
|
tg->last_low_overflow_time[rw] = jiffies; |
|
if (throtl_can_upgrade(td, tg)) { |
|
throtl_upgrade_state(td); |
|
goto again; |
|
} |
|
break; |
|
} |
|
|
|
/* within limits, let's charge and dispatch directly */ |
|
throtl_charge_bio(tg, bio); |
|
|
|
/* |
|
* We need to trim slice even when bios are not being queued |
|
* otherwise it might happen that a bio is not queued for |
|
* a long time and slice keeps on extending and trim is not |
|
* called for a long time. Now if limits are reduced suddenly |
|
* we take into account all the IO dispatched so far at new |
|
* low rate and * newly queued IO gets a really long dispatch |
|
* time. |
|
* |
|
* So keep on trimming slice even if bio is not queued. |
|
*/ |
|
throtl_trim_slice(tg, rw); |
|
|
|
/* |
|
* @bio passed through this layer without being throttled. |
|
* Climb up the ladder. If we're already at the top, it |
|
* can be executed directly. |
|
*/ |
|
qn = &tg->qnode_on_parent[rw]; |
|
sq = sq->parent_sq; |
|
tg = sq_to_tg(sq); |
|
if (!tg) |
|
goto out_unlock; |
|
} |
|
|
|
/* out-of-limit, queue to @tg */ |
|
throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
|
rw == READ ? 'R' : 'W', |
|
tg->bytes_disp[rw], bio->bi_iter.bi_size, |
|
tg_bps_limit(tg, rw), |
|
tg->io_disp[rw], tg_iops_limit(tg, rw), |
|
sq->nr_queued[READ], sq->nr_queued[WRITE]); |
|
|
|
tg->last_low_overflow_time[rw] = jiffies; |
|
|
|
td->nr_queued[rw]++; |
|
throtl_add_bio_tg(bio, qn, tg); |
|
throttled = true; |
|
|
|
/* |
|
* Update @tg's dispatch time and force schedule dispatch if @tg |
|
* was empty before @bio. The forced scheduling isn't likely to |
|
* cause undue delay as @bio is likely to be dispatched directly if |
|
* its @tg's disptime is not in the future. |
|
*/ |
|
if (tg->flags & THROTL_TG_WAS_EMPTY) { |
|
tg_update_disptime(tg); |
|
throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
|
} |
|
|
|
out_unlock: |
|
spin_unlock_irq(&q->queue_lock); |
|
out: |
|
bio_set_flag(bio, BIO_THROTTLED); |
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
if (throttled || !td->track_bio_latency) |
|
bio->bi_issue.value |= BIO_ISSUE_THROTL_SKIP_LATENCY; |
|
#endif |
|
rcu_read_unlock(); |
|
return throttled; |
|
} |
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
static void throtl_track_latency(struct throtl_data *td, sector_t size, |
|
int op, unsigned long time) |
|
{ |
|
struct latency_bucket *latency; |
|
int index; |
|
|
|
if (!td || td->limit_index != LIMIT_LOW || |
|
!(op == REQ_OP_READ || op == REQ_OP_WRITE) || |
|
!blk_queue_nonrot(td->queue)) |
|
return; |
|
|
|
index = request_bucket_index(size); |
|
|
|
latency = get_cpu_ptr(td->latency_buckets[op]); |
|
latency[index].total_latency += time; |
|
latency[index].samples++; |
|
put_cpu_ptr(td->latency_buckets[op]); |
|
} |
|
|
|
void blk_throtl_stat_add(struct request *rq, u64 time_ns) |
|
{ |
|
struct request_queue *q = rq->q; |
|
struct throtl_data *td = q->td; |
|
|
|
throtl_track_latency(td, blk_rq_stats_sectors(rq), req_op(rq), |
|
time_ns >> 10); |
|
} |
|
|
|
void blk_throtl_bio_endio(struct bio *bio) |
|
{ |
|
struct blkcg_gq *blkg; |
|
struct throtl_grp *tg; |
|
u64 finish_time_ns; |
|
unsigned long finish_time; |
|
unsigned long start_time; |
|
unsigned long lat; |
|
int rw = bio_data_dir(bio); |
|
|
|
blkg = bio->bi_blkg; |
|
if (!blkg) |
|
return; |
|
tg = blkg_to_tg(blkg); |
|
if (!tg->td->limit_valid[LIMIT_LOW]) |
|
return; |
|
|
|
finish_time_ns = ktime_get_ns(); |
|
tg->last_finish_time = finish_time_ns >> 10; |
|
|
|
start_time = bio_issue_time(&bio->bi_issue) >> 10; |
|
finish_time = __bio_issue_time(finish_time_ns) >> 10; |
|
if (!start_time || finish_time <= start_time) |
|
return; |
|
|
|
lat = finish_time - start_time; |
|
/* this is only for bio based driver */ |
|
if (!(bio->bi_issue.value & BIO_ISSUE_THROTL_SKIP_LATENCY)) |
|
throtl_track_latency(tg->td, bio_issue_size(&bio->bi_issue), |
|
bio_op(bio), lat); |
|
|
|
if (tg->latency_target && lat >= tg->td->filtered_latency) { |
|
int bucket; |
|
unsigned int threshold; |
|
|
|
bucket = request_bucket_index(bio_issue_size(&bio->bi_issue)); |
|
threshold = tg->td->avg_buckets[rw][bucket].latency + |
|
tg->latency_target; |
|
if (lat > threshold) |
|
tg->bad_bio_cnt++; |
|
/* |
|
* Not race free, could get wrong count, which means cgroups |
|
* will be throttled |
|
*/ |
|
tg->bio_cnt++; |
|
} |
|
|
|
if (time_after(jiffies, tg->bio_cnt_reset_time) || tg->bio_cnt > 1024) { |
|
tg->bio_cnt_reset_time = tg->td->throtl_slice + jiffies; |
|
tg->bio_cnt /= 2; |
|
tg->bad_bio_cnt /= 2; |
|
} |
|
} |
|
#endif |
|
|
|
int blk_throtl_init(struct request_queue *q) |
|
{ |
|
struct throtl_data *td; |
|
int ret; |
|
|
|
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); |
|
if (!td) |
|
return -ENOMEM; |
|
td->latency_buckets[READ] = __alloc_percpu(sizeof(struct latency_bucket) * |
|
LATENCY_BUCKET_SIZE, __alignof__(u64)); |
|
if (!td->latency_buckets[READ]) { |
|
kfree(td); |
|
return -ENOMEM; |
|
} |
|
td->latency_buckets[WRITE] = __alloc_percpu(sizeof(struct latency_bucket) * |
|
LATENCY_BUCKET_SIZE, __alignof__(u64)); |
|
if (!td->latency_buckets[WRITE]) { |
|
free_percpu(td->latency_buckets[READ]); |
|
kfree(td); |
|
return -ENOMEM; |
|
} |
|
|
|
INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
|
throtl_service_queue_init(&td->service_queue); |
|
|
|
q->td = td; |
|
td->queue = q; |
|
|
|
td->limit_valid[LIMIT_MAX] = true; |
|
td->limit_index = LIMIT_MAX; |
|
td->low_upgrade_time = jiffies; |
|
td->low_downgrade_time = jiffies; |
|
|
|
/* activate policy */ |
|
ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
|
if (ret) { |
|
free_percpu(td->latency_buckets[READ]); |
|
free_percpu(td->latency_buckets[WRITE]); |
|
kfree(td); |
|
} |
|
return ret; |
|
} |
|
|
|
void blk_throtl_exit(struct request_queue *q) |
|
{ |
|
BUG_ON(!q->td); |
|
del_timer_sync(&q->td->service_queue.pending_timer); |
|
throtl_shutdown_wq(q); |
|
blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
|
free_percpu(q->td->latency_buckets[READ]); |
|
free_percpu(q->td->latency_buckets[WRITE]); |
|
kfree(q->td); |
|
} |
|
|
|
void blk_throtl_register_queue(struct request_queue *q) |
|
{ |
|
struct throtl_data *td; |
|
int i; |
|
|
|
td = q->td; |
|
BUG_ON(!td); |
|
|
|
if (blk_queue_nonrot(q)) { |
|
td->throtl_slice = DFL_THROTL_SLICE_SSD; |
|
td->filtered_latency = LATENCY_FILTERED_SSD; |
|
} else { |
|
td->throtl_slice = DFL_THROTL_SLICE_HD; |
|
td->filtered_latency = LATENCY_FILTERED_HD; |
|
for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { |
|
td->avg_buckets[READ][i].latency = DFL_HD_BASELINE_LATENCY; |
|
td->avg_buckets[WRITE][i].latency = DFL_HD_BASELINE_LATENCY; |
|
} |
|
} |
|
#ifndef CONFIG_BLK_DEV_THROTTLING_LOW |
|
/* if no low limit, use previous default */ |
|
td->throtl_slice = DFL_THROTL_SLICE_HD; |
|
#endif |
|
|
|
td->track_bio_latency = !queue_is_mq(q); |
|
if (!td->track_bio_latency) |
|
blk_stat_enable_accounting(q); |
|
} |
|
|
|
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
|
ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page) |
|
{ |
|
if (!q->td) |
|
return -EINVAL; |
|
return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice)); |
|
} |
|
|
|
ssize_t blk_throtl_sample_time_store(struct request_queue *q, |
|
const char *page, size_t count) |
|
{ |
|
unsigned long v; |
|
unsigned long t; |
|
|
|
if (!q->td) |
|
return -EINVAL; |
|
if (kstrtoul(page, 10, &v)) |
|
return -EINVAL; |
|
t = msecs_to_jiffies(v); |
|
if (t == 0 || t > MAX_THROTL_SLICE) |
|
return -EINVAL; |
|
q->td->throtl_slice = t; |
|
return count; |
|
} |
|
#endif |
|
|
|
static int __init throtl_init(void) |
|
{ |
|
kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
|
if (!kthrotld_workqueue) |
|
panic("Failed to create kthrotld\n"); |
|
|
|
return blkcg_policy_register(&blkcg_policy_throtl); |
|
} |
|
|
|
module_init(throtl_init);
|
|
|