Re: [PATCH V3 01/16] block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler
From: kbuild test robot
Date: Wed Apr 12 2017 - 16:19:57 EST
Hi Paolo,
[auto build test ERROR on block/for-next]
[also build test ERROR on v4.11-rc6 next-20170412]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Paolo-Valente/Introduce-the-BFQ-I-O-scheduler/20170412-021320
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: blackfin-allyesconfig (attached as .config)
compiler: bfin-uclinux-gcc (GCC) 6.2.0
reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=blackfin
Note: the linux-review/Paolo-Valente/Introduce-the-BFQ-I-O-scheduler/20170412-021320 HEAD 36eb6533f8b6705991185201f75e98880cd223f7 builds fine.
It only hurts bisectibility.
All error/warnings (new ones prefixed by >>):
block/bfq-iosched.c: In function 'bfq_update_peak_rate':
>> block/bfq-iosched.c:2674:6: error: 'delta_usecs' undeclared (first use in this function)
if (delta_usecs < 1000) {
^~~~~~~~~~~
block/bfq-iosched.c:2674:6: note: each undeclared identifier is reported only once for each function it appears in
>> block/bfq-iosched.c:2739:22: error: invalid storage class for function 'bfq_smallest_from_now'
static unsigned long bfq_smallest_from_now(void)
^~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2739:1: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
static unsigned long bfq_smallest_from_now(void)
^~~~~~
>> block/bfq-iosched.c:2774:13: error: invalid storage class for function 'bfq_bfqq_expire'
static void bfq_bfqq_expire(struct bfq_data *bfqd,
^~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2823:13: error: invalid storage class for function 'bfq_bfqq_budget_timeout'
static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq)
^~~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2839:13: error: invalid storage class for function 'bfq_may_expire_for_budg_timeout'
static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2858:13: error: invalid storage class for function 'bfq_bfqq_may_idle'
static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
^~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2901:13: error: invalid storage class for function 'bfq_bfqq_must_idle'
static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq)
^~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:2913:26: error: invalid storage class for function 'bfq_select_queue'
static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd)
^~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3012:24: error: invalid storage class for function 'bfq_dispatch_rq_from_bfqq'
static struct request *bfq_dispatch_rq_from_bfqq(struct bfq_data *bfqd,
^~~~~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3044:13: error: invalid storage class for function 'bfq_has_work'
static bool bfq_has_work(struct blk_mq_hw_ctx *hctx)
^~~~~~~~~~~~
>> block/bfq-iosched.c:3056:24: error: invalid storage class for function '__bfq_dispatch_request'
static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
^~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3141:24: error: invalid storage class for function 'bfq_dispatch_request'
static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
^~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3160:13: error: invalid storage class for function 'bfq_put_queue'
static void bfq_put_queue(struct bfq_queue *bfqq)
^~~~~~~~~~~~~
>> block/bfq-iosched.c:3173:13: error: invalid storage class for function 'bfq_exit_bfqq'
static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
^~~~~~~~~~~~~
>> block/bfq-iosched.c:3185:13: error: invalid storage class for function 'bfq_exit_icq_bfqq'
static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync)
^~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3203:13: error: invalid storage class for function 'bfq_exit_icq'
static void bfq_exit_icq(struct io_cq *icq)
^~~~~~~~~~~~
>> block/bfq-iosched.c:3216:1: error: invalid storage class for function 'bfq_set_next_ioprio_data'
bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
^~~~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3262:13: error: invalid storage class for function 'bfq_check_ioprio_change'
static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
^~~~~~~~~~~~~~~~~~~~~~~
>> block/bfq-iosched.c:3290:13: error: invalid storage class for function 'bfq_init_bfqq'
static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
^~~~~~~~~~~~~
vim +/delta_usecs +2674 block/bfq-iosched.c
2668 else
2669 delta = ktime_get();
2670 delta = ktime_sub(delta, bfqd->last_budget_start);
2671 usecs = ktime_to_us(delta);
2672
2673 /* don't use too short time intervals */
> 2674 if (delta_usecs < 1000) {
2675 return false;
2676
2677 /*
2678 * Calculate the bandwidth for the last slice. We use a 64 bit
2679 * value to store the peak rate, in sectors per usec in fixed
2680 * point math. We do so to have enough precision in the estimate
2681 * and to avoid overflows.
2682 */
2683 bw = (u64)bfqq->entity.service << BFQ_RATE_SHIFT;
2684 do_div(bw, (unsigned long)usecs);
2685
2686 timeout = jiffies_to_msecs(bfqd->bfq_timeout);
2687
2688 /*
2689 * Use only long (> 20ms) intervals to filter out spikes for
2690 * the peak rate estimation.
2691 */
2692 if (usecs > 20000) {
2693 if (bw > bfqd->peak_rate) {
2694 bfqd->peak_rate = bw;
2695 update = 1;
2696 bfq_log(bfqd, "new peak_rate=%llu", bw);
2697 }
2698
2699 update |= bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES - 1;
2700
2701 if (bfqd->peak_rate_samples < BFQ_PEAK_RATE_SAMPLES)
2702 bfqd->peak_rate_samples++;
2703
2704 if (bfqd->peak_rate_samples == BFQ_PEAK_RATE_SAMPLES &&
2705 update && bfqd->bfq_user_max_budget == 0) {
2706 bfqd->bfq_max_budget =
2707 bfq_calc_max_budget(bfqd->peak_rate,
2708 timeout);
2709 bfq_log(bfqd, "new max_budget=%d",
2710 bfqd->bfq_max_budget);
2711 }
2712 }
2713
2714 /*
2715 * A process is considered ``slow'' (i.e., seeky, so that we
2716 * cannot treat it fairly in the service domain, as it would
2717 * slow down too much the other processes) if, when a slice
2718 * ends for whatever reason, it has received service at a
2719 * rate that would not be high enough to complete the budget
2720 * before the budget timeout expiration.
2721 */
2722 expected = bw * 1000 * timeout >> BFQ_RATE_SHIFT;
2723
2724 /*
2725 * Caveat: processes doing IO in the slower disk zones will
2726 * tend to be slow(er) even if not seeky. And the estimated
2727 * peak rate will actually be an average over the disk
2728 * surface. Hence, to not be too harsh with unlucky processes,
2729 * we keep a budget/3 margin of safety before declaring a
2730 * process slow.
2731 */
2732 return expected > (4 * bfqq->entity.budget) / 3;
2733 }
2734
2735 /*
2736 * Return the farthest past time instant according to jiffies
2737 * macros.
2738 */
> 2739 static unsigned long bfq_smallest_from_now(void)
2740 {
2741 return jiffies - MAX_JIFFY_OFFSET;
2742 }
2743
2744 /**
2745 * bfq_bfqq_expire - expire a queue.
2746 * @bfqd: device owning the queue.
2747 * @bfqq: the queue to expire.
2748 * @compensate: if true, compensate for the time spent idling.
2749 * @reason: the reason causing the expiration.
2750 *
2751 *
2752 * If the process associated with the queue is slow (i.e., seeky), or
2753 * in case of budget timeout, or, finally, if it is async, we
2754 * artificially charge it an entire budget (independently of the
2755 * actual service it received). As a consequence, the queue will get
2756 * higher timestamps than the correct ones upon reactivation, and
2757 * hence it will be rescheduled as if it had received more service
2758 * than what it actually received. In the end, this class of processes
2759 * will receive less service in proportion to how slowly they consume
2760 * their budgets (and hence how seriously they tend to lower the
2761 * throughput).
2762 *
2763 * In contrast, when a queue expires because it has been idling for
2764 * too much or because it exhausted its budget, we do not touch the
2765 * amount of service it has received. Hence when the queue will be
2766 * reactivated and its timestamps updated, the latter will be in sync
2767 * with the actual service received by the queue until expiration.
2768 *
2769 * Charging a full budget to the first type of queues and the exact
2770 * service to the others has the effect of using the WF2Q+ policy to
2771 * schedule the former on a timeslice basis, without violating the
2772 * service domain guarantees of the latter.
2773 */
> 2774 static void bfq_bfqq_expire(struct bfq_data *bfqd,
2775 struct bfq_queue *bfqq,
2776 bool compensate,
2777 enum bfqq_expiration reason)
2778 {
2779 bool slow;
2780 int ref;
2781
2782 /*
2783 * Update device peak rate for autotuning and check whether the
2784 * process is slow (see bfq_update_peak_rate).
2785 */
2786 slow = bfq_update_peak_rate(bfqd, bfqq, compensate);
2787
2788 /*
2789 * As above explained, 'punish' slow (i.e., seeky), timed-out
2790 * and async queues, to favor sequential sync workloads.
2791 */
2792 if (slow || reason == BFQQE_BUDGET_TIMEOUT)
2793 bfq_bfqq_charge_full_budget(bfqq);
2794
2795 if (reason == BFQQE_TOO_IDLE &&
2796 bfqq->entity.service <= 2 * bfqq->entity.budget / 10)
2797 bfq_clear_bfqq_IO_bound(bfqq);
2798
2799 bfq_log_bfqq(bfqd, bfqq,
2800 "expire (%d, slow %d, num_disp %d, idle_win %d)", reason,
2801 slow, bfqq->dispatched, bfq_bfqq_idle_window(bfqq));
2802
2803 /*
2804 * Increase, decrease or leave budget unchanged according to
2805 * reason.
2806 */
2807 __bfq_bfqq_recalc_budget(bfqd, bfqq, reason);
2808 ref = bfqq->ref;
2809 __bfq_bfqq_expire(bfqd, bfqq);
2810
2811 /* mark bfqq as waiting a request only if a bic still points to it */
2812 if (ref > 1 && !bfq_bfqq_busy(bfqq) &&
2813 reason != BFQQE_BUDGET_TIMEOUT &&
2814 reason != BFQQE_BUDGET_EXHAUSTED)
2815 bfq_mark_bfqq_non_blocking_wait_rq(bfqq);
2816 }
2817
2818 /*
2819 * Budget timeout is not implemented through a dedicated timer, but
2820 * just checked on request arrivals and completions, as well as on
2821 * idle timer expirations.
2822 */
> 2823 static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq)
2824 {
2825 if (bfq_bfqq_budget_new(bfqq) ||
2826 time_is_after_jiffies(bfqq->budget_timeout))
2827 return false;
2828 return true;
2829 }
2830
2831 /*
2832 * If we expire a queue that is actively waiting (i.e., with the
2833 * device idled) for the arrival of a new request, then we may incur
2834 * the timestamp misalignment problem described in the body of the
2835 * function __bfq_activate_entity. Hence we return true only if this
2836 * condition does not hold, or if the queue is slow enough to deserve
2837 * only to be kicked off for preserving a high throughput.
2838 */
> 2839 static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq)
2840 {
2841 bfq_log_bfqq(bfqq->bfqd, bfqq,
2842 "may_budget_timeout: wait_request %d left %d timeout %d",
2843 bfq_bfqq_wait_request(bfqq),
2844 bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3,
2845 bfq_bfqq_budget_timeout(bfqq));
2846
2847 return (!bfq_bfqq_wait_request(bfqq) ||
2848 bfq_bfqq_budget_left(bfqq) >= bfqq->entity.budget / 3)
2849 &&
2850 bfq_bfqq_budget_timeout(bfqq);
2851 }
2852
2853 /*
2854 * For a queue that becomes empty, device idling is allowed only if
2855 * this function returns true for the queue. And this function returns
2856 * true only if idling is beneficial for throughput.
2857 */
> 2858 static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
2859 {
2860 struct bfq_data *bfqd = bfqq->bfqd;
2861 bool idling_boosts_thr;
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