函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:block\bfq-iosched.c Create Date:2022-07-27 19:30:47
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：bfq_add_request

函数原型：static void bfq_add_request(struct request *rq)

返回类型：void

参数：

类型参数名称
struct request *rq
1866  bfqq等于RQ_BFQQ(rq)
1867  bfqd等于parent bfq_data
1869  old_wr_coeff等于actor by which the weight of this queue is multiplied
1870  bool interactive = false
1872  bfq_log_bfqq(bfqd, bfqq, "add_request %d", rq_is_sync(rq))
1873  umber of sync and async requests queued [rq_is_sync(rq)]自加
1874  number of queued requests 自加
1876  如果RB_EMPTY_ROOT( & sorted list of pending requests )且bfq_bfqq_sync(bfqq)则
1931  如果 bfqq owning the last completed rq 且非bfq_bfqq_has_short_ttime(bfqq)且ktime_get_ns()减 time of last request completion (ns) 小于200乘NSEC_PER_USEC则
1935  如果 bfqq owning the last completed rq 不等于bfqq且 bfqq owning the last completed rq 不等于Pointer to the waker queue for this queue, i.e., to the* queue Q such that this queue happens to get new I/O right* after some I/O request of Q is completed. For details, see* the comments on the choice of the queue for injection in* bfq_select_queue().则
1972  否则如果 bfqq owning the last completed rq 恒等于Pointer to the waker queue for this queue, i.e., to the* queue Q such that this queue happens to get new I/O right* after some I/O request of Q is completed. For details, see* the comments on the choice of the queue for injection in* bfq_select_queue().且非bfq_bfqq_has_waker(bfqq)则
1989  如果ime_is_before_eq_jiffies(a) return true if a is before or equal to jiffies(last time the inject limit has been decreased, in jiffies + msecs_to_jiffies: - convert milliseconds to jiffies*@m: time in milliseconds* conversion is done as follows:* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)* - 'too large' values [that would result in larger than)则bfq_reset_inject_limit(bfqd, bfqq)
2018  如果bfqq恒等于 bfq_queue in service 且 number of requests dispatched and waiting for completion 恒等于0或last total-service-time sample, see bfq_update_inject_limit() 大于0且* True if some request has been injected during the last service hole.且 number of requests dispatched and waiting for completion 大于0的值且ime_is_before_eq_jiffies(a) return true if a is before or equal to jiffies(last time the inject limit has been decreased, in jiffies + msecs_to_jiffies: - convert milliseconds to jiffies*@m: time in milliseconds* conversion is done as follows:* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)* - 'too large' values [that would result in larger than)则
2024  time of last transition from empty to non-empty (ns) 等于ktime_get_ns()
2031  * Flag set to activate the sampling of the total service time * of a just-arrived first I/O request (see * bfq_update_inject_limit()). This will cause the setting of * waited_rq when the request is finally dispatched. = true
2045  如果 number of requests dispatched and waiting for completion 恒等于0则* True if some request has been injected during the last service hole. = false
2050  RB-tree support functions for inserting/lookup/removal of requests* in a sorted RB tree.
2055  prev等于 fifo isn't expired, next request to serve
2056  next_rq等于Lifted from AS - choose which of rq1 and rq2 that is best served now.* We choose the request that is closer to the head right now. Distance* behind the head is penalized and only allowed to a certain extent.
2057  fifo isn't expired, next request to serve 等于next_rq
2063  如果此条件成立可能性小(为编译器优化)(! true if the device is non rotational and performs queueing && prev != fifo isn't expired, next request to serve )则The following function is not marked as __cold because it is* actually cold, but for the same performance goal described in the* comments on the likely() at the beginning of* bfq_setup_cooperator()
2066  如果非bfq_bfqq_busy(bfqq)则bfq_bfqq_handle_idle_busy_switch(bfqd, bfqq, old_wr_coeff, rq, & interactive)
2069  否则
2070  如果 if set to true, low-latency heuristics are enabled 且old_wr_coeff恒等于1且非rq_is_sync(rq)且ime_is_before_jiffies(a) return true if a is before jiffies (Start time of the current weight-raising period if* the @bfq-queue is being weight-raised, otherwise* finish time of the last weight-raising period. + * Minimum period between request arrivals after which * weight-raising may be reactivated for an already busy async * queue (in jiffies).)则
2074  actor by which the weight of this queue is multiplied 等于* Maximum factor by which the weight of a weight-raised queue * is multiplied.
2075  current maximum weight-raising time for this queue 等于bfq_wr_duration(bfqd)
2077  number of weight-raised busy @bfq_queues 自加
2078  flag, set to request a weight, ioprio or ioprio_class change 等于1
2080  如果prev不等于 fifo isn't expired, next request to serve 则q_updated_next_req - update the queue after a new next_rq selection
2110  如果 if set to true, low-latency heuristics are enabled 且old_wr_coeff恒等于1或actor by which the weight of this queue is multiplied 恒等于1或interactive的值则Start time of the current weight-raising period if* the @bfq-queue is being weight-raised, otherwise* finish time of the last weight-raising period.等于jiffies
调用者
名称描述
__bfq_insert_requestrns true if it causes the idle timer to be disabled