diff options
| -rw-r--r-- | block/bfq-iosched.c | 87 |
1 files changed, 49 insertions, 38 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index c25955c25e033..33b63bc4a64b6 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -724,6 +724,44 @@ static void bfq_updated_next_req(struct bfq_data *bfqd, } } +static unsigned int bfq_wr_duration(struct bfq_data *bfqd) +{ + u64 dur; + + if (bfqd->bfq_wr_max_time > 0) + return bfqd->bfq_wr_max_time; + + dur = bfqd->RT_prod; + do_div(dur, bfqd->peak_rate); + + /* + * Limit duration between 3 and 13 seconds. Tests show that + * higher values than 13 seconds often yield the opposite of + * the desired result, i.e., worsen responsiveness by letting + * non-interactive and non-soft-real-time applications + * preserve weight raising for a too long time interval. + * + * On the other end, lower values than 3 seconds make it + * difficult for most interactive tasks to complete their jobs + * before weight-raising finishes. + */ + if (dur > msecs_to_jiffies(13000)) + dur = msecs_to_jiffies(13000); + else if (dur < msecs_to_jiffies(3000)) + dur = msecs_to_jiffies(3000); + + return dur; +} + +/* switch back from soft real-time to interactive weight raising */ +static void switch_back_to_interactive_wr(struct bfq_queue *bfqq, + struct bfq_data *bfqd) +{ + bfqq->wr_coeff = bfqd->bfq_wr_coeff; + bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); + bfqq->last_wr_start_finish = bfqq->wr_start_at_switch_to_srt; +} + static void bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, struct bfq_io_cq *bic, bool bfq_already_existing) @@ -750,10 +788,16 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, if (bfqq->wr_coeff > 1 && (bfq_bfqq_in_large_burst(bfqq) || time_is_before_jiffies(bfqq->last_wr_start_finish + bfqq->wr_cur_max_time))) { - bfq_log_bfqq(bfqq->bfqd, bfqq, - "resume state: switching off wr"); - - bfqq->wr_coeff = 1; + if (bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + !bfq_bfqq_in_large_burst(bfqq) && + time_is_after_eq_jiffies(bfqq->wr_start_at_switch_to_srt + + bfq_wr_duration(bfqd))) { + switch_back_to_interactive_wr(bfqq, bfqd); + } else { + bfqq->wr_coeff = 1; + bfq_log_bfqq(bfqq->bfqd, bfqq, + "resume state: switching off wr"); + } } /* make sure weight will be updated, however we got here */ @@ -1173,35 +1217,6 @@ static bool bfq_bfqq_update_budg_for_activation(struct bfq_data *bfqd, return wr_or_deserves_wr; } -static unsigned int bfq_wr_duration(struct bfq_data *bfqd) -{ - u64 dur; - - if (bfqd->bfq_wr_max_time > 0) - return bfqd->bfq_wr_max_time; - - dur = bfqd->RT_prod; - do_div(dur, bfqd->peak_rate); - - /* - * Limit duration between 3 and 13 seconds. Tests show that - * higher values than 13 seconds often yield the opposite of - * the desired result, i.e., worsen responsiveness by letting - * non-interactive and non-soft-real-time applications - * preserve weight raising for a too long time interval. - * - * On the other end, lower values than 3 seconds make it - * difficult for most interactive tasks to complete their jobs - * before weight-raising finishes. - */ - if (dur > msecs_to_jiffies(13000)) - dur = msecs_to_jiffies(13000); - else if (dur < msecs_to_jiffies(3000)) - dur = msecs_to_jiffies(3000); - - return dur; -} - /* * Return the farthest future time instant according to jiffies * macros. @@ -3501,11 +3516,7 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_wr_duration(bfqd))) bfq_bfqq_end_wr(bfqq); else { - /* switch back to interactive wr */ - bfqq->wr_coeff = bfqd->bfq_wr_coeff; - bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); - bfqq->last_wr_start_finish = - bfqq->wr_start_at_switch_to_srt; + switch_back_to_interactive_wr(bfqq, bfqd); bfqq->entity.prio_changed = 1; } } |