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lock
#ifndef lock_h#define lock_h#include <stdint.h>#include <string.h>#include "mydef.h"#include "now.h"#define debug_lock 1typedef struct { intptr_t lck; uintptr_t tid; uintptr_t nr;#if debug_lock const char* file; uintptr_t line;#endif} lock_t;#define lock_initial {0}#define lock_initial_locked {1, 0, 1}static __attribute__((unused)) lock_t lock_val = lock_initial;#if (debug_lock == 2)#define locktrace_begin() uintptr_t tms = now();#define lock_backtrace(lkp) do { uintptr_t current = now(); if (tms == 0) { tms = current; } if (current > tms + 3000) { tms = current - 2000; logmsg("locktrace: %d %s:%d\n", (int) lkp->lck, lkp->file, (int) lkp->line); } } while (0)#else#define locktrace_begin() (void) 0#define lock_backtrace(x) (void) 0#endif#if debug_lock #define log_lock(ptr, l, f) do {ptr->line = l; ptr->file = f;} while (0) #define log_unlock(ptr) do {ptr->line = -1; ptr->file = "";} while (0)#else #define log_lock(ptr, l, f) (void) (0) #define log_unlock(ptr) (void) (0)#endif#ifdef __linux__ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #define my_lock(lkp, re) do { lock_t* ptr = lkp; if (!__sync_bool_compare_and_swap(&ptr->lck, 0, 1)) { if (ptr->lck == 2) { syscall(__NR_futex, &ptr->lck, FUTEX_WAIT, 2, NULL, NULL, 0); } locktrace_begin(); while (0 != __sync_lock_test_and_set(&ptr->lck, 2)) { syscall(__NR_futex, &ptr->lck, FUTEX_WAIT, 2, NULL, NULL, 0); lock_backtrace(ptr); } } my_assert2(ptr->lck != 0, "lck = %d", ptr->lck); my_assert2(ptr->nr == 0, "lck = %d, nr = %d, %d@%s", ptr->lck, ptr->nr, ptr->line, ptr->file); log_lock(ptr, __LINE__, __FILE__); my_assert(ptr->tid == 0); if (re) { ptr->tid = systid(); } ++ptr->nr; } while (0) #define unlock(lkp) do { lock_t* ptr = lkp; my_assert2(ptr->lck != 0, "lck = %d, nr = %d", ptr->lck, ptr->nr); --ptr->nr; wmb(); if (ptr->nr > 0) { my_assert2(ptr->tid != 0, "tid != 0, ptr->nr = %d, lck = %d, %d@%s", ptr->nr, ptr->lck, ptr->line, ptr->file); } else { ptr->tid = 0; /* wmb(); */ log_unlock(ptr); if (2 == __sync_lock_test_and_set(&ptr->lck, 0)) { while (-1 == syscall(__NR_futex, &ptr->lck, FUTEX_WAKE, 1, NULL, NULL, 0)); } } } while (0)#else #define my_lock(lkp, re) do { lock_t* ptr = lkp; locktrace_begin(); while (!__sync_bool_compare_and_swap((void **) &ptr->lck, (void *) 0, (void *) 1)) { sched_yield(); lock_backtrace(ptr); } log_lock(ptr, __LINE__, __FILE__); my_assert(ptr->tid == 0); if (re) { ptr->tid = systid(); } ++ptr->nr; } while (0) #define unlock(lkp) do { lock_t* ptr = lkp; my_assert(ptr->lck != 0); --ptr->nr; wmb(); if (ptr->nr > 0) { my_assert(ptr->tid != 0); } else { ptr->tid = 0; /* wmb(); */ log_unlock(ptr); ptr->lck = 0; } } while (0)#endif#define lock(lkp) my_lock(lkp, 0)#define relock(lkp) do { lock_t* ptr = lkp; /* this rmb() is here to assure to see ptr->tid = 0 in unlock */ /* if thread exit after unlock(), then another thread is spwaned with same tid */ /* on another cpu core and then call lock_recursive. */ /* all the above happens so quickly that the other cpu core does not see ptr->tid = 0 */ /* it is so impossible to happen that I comment the "correct" implemention. */ /* rmb(); */ if (ptr->tid == systid()) { /* if true, it‘s same thread, event in another cpu core, no mb() is needed. */ ++ptr->nr; } else { my_lock(lkp, 1); } } while (0)static __attribute__((unused)) inline intptr_t my_try_lock(lock_t* lkp, uintptr_t re, uintptr_t line, const char* file){ if (!__sync_bool_compare_and_swap((void **) &((lkp)->lck), (void *) 0, (void *) 1)) { return -1; } log_lock(lkp, line, file); my_assert(lkp->tid == 0); if (re) { lkp->tid = systid(); } ++lkp->nr; return 0;}#define try_lock(lkp) my_try_lock(lkp, 0, __LINE__, __FILE__)#define retry_lock(lkp) my_try_lock(lkp, 1, __LINE__, __FILE__)typedef struct { intptr_t nr;} rwlock_t;#define read_write_max 8000#define rw_lock_initial {read_write_max}static __attribute__((unused)) rwlock_t rw_lock_val = rw_lock_initial;#define read_write_lock(lckp, val) do { rwlock_t* lck = lckp; do { intptr_t n = __sync_sub_and_fetch(&lck->nr, val); if (n >= 0) { break; } __sync_add_and_fetch(&lck->nr, val); sched_yield(); } while (1); } while (0)#define read_write_unlock(lckp, val) do { rwlock_t* lck = lckp; __sync_add_and_fetch(&lck->nr, val); } while (0)#define read_lock(lckp) read_write_lock(lckp, 1)#define write_lock(lckp) read_write_lock(lckp, read_write_max)#define read_unlock(lckp) read_write_unlock(lckp, 1)#define write_unlock(lckp) read_write_unlock(lckp, read_write_max)#endif
lock
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