X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2F__lock.c;h=d1734096b1ab81d024372d234f4d1e50eda7dad2;hp=21c85fc0636f71f6eb715459590f78ec4e0aaac5;hb=f34d0ea511e552851c8c6148fb113816f41e6759;hpb=6232b96f5153d0b718054a8bc569fcd7d596bab2 diff --git a/src/thread/__lock.c b/src/thread/__lock.c index 21c85fc0..d1734096 100644 --- a/src/thread/__lock.c +++ b/src/thread/__lock.c @@ -1,11 +1,32 @@ #include "pthread_impl.h" +void __lock_2(volatile int *l) +{ + if (!__syscall(SYS_futex, l, FUTEX_LOCK_PI, 0, 0)) + return; + int old, tid = __pthread_self()->tid; + while ((old = a_cas(l, 0, tid))) { + a_cas(l, old, old|INT_MIN); + __syscall(SYS_futex, l, FUTEX_WAIT, old|INT_MIN, 0); + } +} + void __lock(volatile int *l) { - int spins=10000; - /* Do not use futexes because we insist that unlocking is a simple - * assignment to optimize non-pathological code with no contention. */ - while (a_xchg(l, 1)) - if (spins) spins--, a_spin(); - else __syscall(SYS_sched_yield); + if (a_cas(l, 0, __pthread_self()->tid)) __lock_2(l); +} + +void __unlock_2(volatile int *l) +{ + if (__syscall(SYS_futex, l, FUTEX_UNLOCK_PI)) { + *l = 0; + __syscall(SYS_futex, l, FUTEX_WAKE, 1); + } +} + +void __unlock(volatile int *l) +{ + int old = *l; + if (!(old & INT_MIN) && a_cas(l, old, 0)==old) return; + __unlock_2(l); }