1 // SPDX-License-Identifier: GPL-2.0 2 #include "bcachefs.h" 3 #include "clock.h" 4 5 #include <linux/freezer.h> 6 #include <linux/kthread.h> 7 #include <linux/preempt.h> 8 9 static inline long io_timer_cmp(io_timer_heap *h, 10 struct io_timer *l, 11 struct io_timer *r) 12 { 13 return l->expire - r->expire; 14 } 15 16 void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer) 17 { 18 size_t i; 19 20 spin_lock(&clock->timer_lock); 21 22 if (time_after_eq((unsigned long) atomic64_read(&clock->now), 23 timer->expire)) { 24 spin_unlock(&clock->timer_lock); 25 timer->fn(timer); 26 return; 27 } 28 29 for (i = 0; i < clock->timers.used; i++) 30 if (clock->timers.data[i] == timer) 31 goto out; 32 33 BUG_ON(!heap_add(&clock->timers, timer, io_timer_cmp, NULL)); 34 out: 35 spin_unlock(&clock->timer_lock); 36 } 37 38 void bch2_io_timer_del(struct io_clock *clock, struct io_timer *timer) 39 { 40 size_t i; 41 42 spin_lock(&clock->timer_lock); 43 44 for (i = 0; i < clock->timers.used; i++) 45 if (clock->timers.data[i] == timer) { 46 heap_del(&clock->timers, i, io_timer_cmp, NULL); 47 break; 48 } 49 50 spin_unlock(&clock->timer_lock); 51 } 52 53 struct io_clock_wait { 54 struct io_timer io_timer; 55 struct timer_list cpu_timer; 56 struct task_struct *task; 57 int expired; 58 }; 59 60 static void io_clock_wait_fn(struct io_timer *timer) 61 { 62 struct io_clock_wait *wait = container_of(timer, 63 struct io_clock_wait, io_timer); 64 65 wait->expired = 1; 66 wake_up_process(wait->task); 67 } 68 69 static void io_clock_cpu_timeout(struct timer_list *timer) 70 { 71 struct io_clock_wait *wait = container_of(timer, 72 struct io_clock_wait, cpu_timer); 73 74 wait->expired = 1; 75 wake_up_process(wait->task); 76 } 77 78 void bch2_io_clock_schedule_timeout(struct io_clock *clock, unsigned long until) 79 { 80 struct io_clock_wait wait; 81 82 /* XXX: calculate sleep time rigorously */ 83 wait.io_timer.expire = until; 84 wait.io_timer.fn = io_clock_wait_fn; 85 wait.task = current; 86 wait.expired = 0; 87 bch2_io_timer_add(clock, &wait.io_timer); 88 89 schedule(); 90 91 bch2_io_timer_del(clock, &wait.io_timer); 92 } 93 94 void bch2_kthread_io_clock_wait(struct io_clock *clock, 95 unsigned long io_until, 96 unsigned long cpu_timeout) 97 { 98 bool kthread = (current->flags & PF_KTHREAD) != 0; 99 struct io_clock_wait wait; 100 101 wait.io_timer.expire = io_until; 102 wait.io_timer.fn = io_clock_wait_fn; 103 wait.task = current; 104 wait.expired = 0; 105 bch2_io_timer_add(clock, &wait.io_timer); 106 107 timer_setup_on_stack(&wait.cpu_timer, io_clock_cpu_timeout, 0); 108 109 if (cpu_timeout != MAX_SCHEDULE_TIMEOUT) 110 mod_timer(&wait.cpu_timer, cpu_timeout + jiffies); 111 112 do { 113 set_current_state(TASK_INTERRUPTIBLE); 114 if (kthread && kthread_should_stop()) 115 break; 116 117 if (wait.expired) 118 break; 119 120 schedule(); 121 try_to_freeze(); 122 } while (0); 123 124 __set_current_state(TASK_RUNNING); 125 del_timer_sync(&wait.cpu_timer); 126 destroy_timer_on_stack(&wait.cpu_timer); 127 bch2_io_timer_del(clock, &wait.io_timer); 128 } 129 130 static struct io_timer *get_expired_timer(struct io_clock *clock, 131 unsigned long now) 132 { 133 struct io_timer *ret = NULL; 134 135 spin_lock(&clock->timer_lock); 136 137 if (clock->timers.used && 138 time_after_eq(now, clock->timers.data[0]->expire)) 139 heap_pop(&clock->timers, ret, io_timer_cmp, NULL); 140 141 spin_unlock(&clock->timer_lock); 142 143 return ret; 144 } 145 146 void __bch2_increment_clock(struct io_clock *clock, unsigned sectors) 147 { 148 struct io_timer *timer; 149 unsigned long now = atomic64_add_return(sectors, &clock->now); 150 151 while ((timer = get_expired_timer(clock, now))) 152 timer->fn(timer); 153 } 154 155 void bch2_io_timers_to_text(struct printbuf *out, struct io_clock *clock) 156 { 157 unsigned long now; 158 unsigned i; 159 160 out->atomic++; 161 spin_lock(&clock->timer_lock); 162 now = atomic64_read(&clock->now); 163 164 for (i = 0; i < clock->timers.used; i++) 165 prt_printf(out, "%ps:\t%li\n", 166 clock->timers.data[i]->fn, 167 clock->timers.data[i]->expire - now); 168 spin_unlock(&clock->timer_lock); 169 --out->atomic; 170 } 171 172 void bch2_io_clock_exit(struct io_clock *clock) 173 { 174 free_heap(&clock->timers); 175 free_percpu(clock->pcpu_buf); 176 } 177 178 int bch2_io_clock_init(struct io_clock *clock) 179 { 180 atomic64_set(&clock->now, 0); 181 spin_lock_init(&clock->timer_lock); 182 183 clock->max_slop = IO_CLOCK_PCPU_SECTORS * num_possible_cpus(); 184 185 clock->pcpu_buf = alloc_percpu(*clock->pcpu_buf); 186 if (!clock->pcpu_buf) 187 return -BCH_ERR_ENOMEM_io_clock_init; 188 189 if (!init_heap(&clock->timers, NR_IO_TIMERS, GFP_KERNEL)) 190 return -BCH_ERR_ENOMEM_io_clock_init; 191 192 return 0; 193 } 194