| 1 | #include <klibc/compiler.h> |
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| 2 | #include <sys/cpu.h> |
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| 3 | #include "thread.h" |
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| 4 | #include "core.h" |
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| 5 | #include <dprintf.h> |
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| 6 | |
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| 7 | void (*sched_hook_func)(void); |
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| 8 | |
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| 9 | /* |
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| 10 | * __schedule() should only be called with interrupts locked out! |
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| 11 | */ |
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| 12 | void __schedule(void) |
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| 13 | { |
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| 14 | static bool in_sched_hook; |
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| 15 | struct thread *curr = current(); |
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| 16 | struct thread *st, *nt, *best; |
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| 17 | |
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| 18 | #if DEBUG |
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| 19 | if (__unlikely(irq_state() & 0x200)) { |
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| 20 | dprintf("In __schedule with interrupts on!\n"); |
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| 21 | kaboom(); |
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| 22 | } |
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| 23 | #endif |
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| 24 | |
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| 25 | /* |
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| 26 | * Are we called from inside sched_hook_func()? If so we'll |
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| 27 | * schedule anyway on the way out. |
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| 28 | */ |
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| 29 | if (in_sched_hook) |
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| 30 | return; |
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| 31 | |
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| 32 | dprintf("Schedule "); |
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| 33 | |
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| 34 | /* Possibly update the information on which we make |
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| 35 | * scheduling decisions. |
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| 36 | */ |
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| 37 | if (sched_hook_func) { |
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| 38 | in_sched_hook = true; |
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| 39 | sched_hook_func(); |
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| 40 | in_sched_hook = false; |
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| 41 | } |
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| 42 | |
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| 43 | /* |
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| 44 | * The unusual form of this walk is because we have to start with |
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| 45 | * the thread *following* curr, and curr may not actually be part |
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| 46 | * of the list anymore (in the case of __exit_thread). |
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| 47 | */ |
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| 48 | best = NULL; |
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| 49 | nt = st = container_of(curr->list.next, struct thread, list); |
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| 50 | do { |
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| 51 | if (__unlikely(nt->thread_magic != THREAD_MAGIC)) { |
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| 52 | dprintf("Invalid thread on thread list %p magic = 0x%08x\n", |
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| 53 | nt, nt->thread_magic); |
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| 54 | kaboom(); |
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| 55 | } |
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| 56 | |
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| 57 | dprintf("Thread %p (%s) ", nt, nt->name); |
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| 58 | if (!nt->blocked) { |
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| 59 | dprintf("runnable priority %d\n", nt->prio); |
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| 60 | if (!best || nt->prio < best->prio) |
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| 61 | best = nt; |
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| 62 | } else { |
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| 63 | dprintf("blocked\n"); |
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| 64 | } |
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| 65 | nt = container_of(nt->list.next, struct thread, list); |
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| 66 | } while (nt != st); |
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| 67 | |
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| 68 | if (!best) |
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| 69 | kaboom(); /* No runnable thread */ |
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| 70 | |
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| 71 | if (best != curr) { |
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| 72 | uint64_t tsc; |
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| 73 | |
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| 74 | asm volatile("rdtsc" : "=A" (tsc)); |
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| 75 | |
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| 76 | dprintf("@ %llu -> %p (%s)\n", tsc, best, best->name); |
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| 77 | __switch_to(best); |
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| 78 | } else { |
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| 79 | dprintf("no change\n"); |
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| 80 | } |
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| 81 | } |
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| 82 | |
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| 83 | /* |
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| 84 | * This can be called from "normal" code... |
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| 85 | */ |
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| 86 | void thread_yield(void) |
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| 87 | { |
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| 88 | irq_state_t irq = irq_save(); |
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| 89 | __schedule(); |
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| 90 | irq_restore(irq); |
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| 91 | } |
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