From e0da8ed3f1c43aeeecd3ef23f943e434ae56dcb7 Mon Sep 17 00:00:00 2001 From: Nicolai Hähnle Date: Sun, 22 Oct 2017 17:38:46 +0200 Subject: util/u_queue: add util_queue_fence_wait_timeout MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit v2: - style fixes - fix missing timeout handling in futex path Reviewed-by: Marek Olšák (v1) --- src/util/futex.h | 9 ++++-- src/util/simple_mtx.h | 2 +- src/util/u_queue.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++- src/util/u_queue.h | 54 ++++++++++++++++++++------------- 4 files changed, 121 insertions(+), 26 deletions(-) diff --git a/src/util/futex.h b/src/util/futex.h index fa42cf4cf5..330e18f03a 100644 --- a/src/util/futex.h +++ b/src/util/futex.h @@ -33,7 +33,7 @@ #include #include -static inline long sys_futex(void *addr1, int op, int val1, struct timespec *timeout, void *addr2, int val3) +static inline long sys_futex(void *addr1, int op, int val1, const struct timespec *timeout, void *addr2, int val3) { return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3); } @@ -48,9 +48,12 @@ static inline int futex_wake_all(uint32_t *addr) return sys_futex(addr, FUTEX_WAKE, INT_MAX, NULL, NULL, 0); } -static inline int futex_wait(uint32_t *addr, int32_t value) +static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout) { - return sys_futex(addr, FUTEX_WAIT, value, NULL, NULL, 0); + /* FUTEX_WAIT_BITSET with FUTEX_BITSET_MATCH_ANY is equivalent to + * FUTEX_WAIT, except that it treats the timeout as absolute. */ + return sys_futex(addr, FUTEX_WAIT_BITSET, value, timeout, NULL, + FUTEX_BITSET_MATCH_ANY); } #endif diff --git a/src/util/simple_mtx.h b/src/util/simple_mtx.h index 0c2602d03b..4186a2d4d6 100644 --- a/src/util/simple_mtx.h +++ b/src/util/simple_mtx.h @@ -79,7 +79,7 @@ simple_mtx_lock(simple_mtx_t *mtx) if (c != 2) c = __sync_lock_test_and_set(&mtx->val, 2); while (c != 0) { - futex_wait(&mtx->val, 2); + futex_wait(&mtx->val, 2, NULL); c = __sync_lock_test_and_set(&mtx->val, 2); } } diff --git a/src/util/u_queue.c b/src/util/u_queue.c index 706ee8b04d..43c28ac6ef 100644 --- a/src/util/u_queue.c +++ b/src/util/u_queue.c @@ -26,6 +26,9 @@ #include "u_queue.h" +#include + +#include "util/os_time.h" #include "util/u_string.h" #include "util/u_thread.h" @@ -91,6 +94,50 @@ remove_from_atexit_list(struct util_queue *queue) * util_queue_fence */ +#ifdef UTIL_QUEUE_FENCE_FUTEX +static bool +do_futex_fence_wait(struct util_queue_fence *fence, + bool timeout, int64_t abs_timeout) +{ + uint32_t v = fence->val; + struct timespec ts; + ts.tv_sec = abs_timeout / (1000*1000*1000); + ts.tv_nsec = abs_timeout % (1000*1000*1000); + + while (v != 0) { + if (v != 2) { + v = p_atomic_cmpxchg(&fence->val, 1, 2); + if (v == 0) + return true; + } + + int r = futex_wait(&fence->val, 2, timeout ? &ts : NULL); + if (timeout && r < 0) { + if (errno == -ETIMEDOUT) + return false; + } + + v = fence->val; + } + + return true; +} + +void +_util_queue_fence_wait(struct util_queue_fence *fence) +{ + do_futex_fence_wait(fence, false, 0); +} + +bool +_util_queue_fence_wait_timeout(struct util_queue_fence *fence, + int64_t abs_timeout) +{ + return do_futex_fence_wait(fence, true, abs_timeout); +} + +#endif + #ifdef UTIL_QUEUE_FENCE_STANDARD void util_queue_fence_signal(struct util_queue_fence *fence) @@ -102,7 +149,7 @@ util_queue_fence_signal(struct util_queue_fence *fence) } void -util_queue_fence_wait(struct util_queue_fence *fence) +_util_queue_fence_wait(struct util_queue_fence *fence) { mtx_lock(&fence->mutex); while (!fence->signalled) @@ -110,6 +157,39 @@ util_queue_fence_wait(struct util_queue_fence *fence) mtx_unlock(&fence->mutex); } +bool +_util_queue_fence_wait_timeout(struct util_queue_fence *fence, + int64_t abs_timeout) +{ + /* This terrible hack is made necessary by the fact that we really want an + * internal interface consistent with os_time_*, but cnd_timedwait is spec'd + * to be relative to the TIME_UTC clock. + */ + int64_t rel = abs_timeout - os_time_get_nano(); + + if (rel > 0) { + struct timespec ts; + + timespec_get(&ts, TIME_UTC); + + ts.tv_sec += abs_timeout / (1000*1000*1000); + ts.tv_nsec += abs_timeout % (1000*1000*1000); + if (ts.tv_nsec >= (1000*1000*1000)) { + ts.tv_sec++; + ts.tv_nsec -= (1000*1000*1000); + } + + mtx_lock(&fence->mutex); + while (!fence->signalled) { + if (cnd_timedwait(&fence->cond, &fence->mutex, &ts) != thrd_success) + break; + } + mtx_unlock(&fence->mutex); + } + + return fence->signalled; +} + void util_queue_fence_init(struct util_queue_fence *fence) { diff --git a/src/util/u_queue.h b/src/util/u_queue.h index 9c911fe6b4..7f9b43d72f 100644 --- a/src/util/u_queue.h +++ b/src/util/u_queue.h @@ -80,26 +80,6 @@ util_queue_fence_destroy(struct util_queue_fence *fence) /* no-op */ } -static inline void -util_queue_fence_wait(struct util_queue_fence *fence) -{ - uint32_t v = fence->val; - - if (likely(v == 0)) - return; - - do { - if (v != 2) { - v = p_atomic_cmpxchg(&fence->val, 1, 2); - if (v == 0) - return; - } - - futex_wait(&fence->val, 2); - v = fence->val; - } while(v != 0); -} - static inline void util_queue_fence_signal(struct util_queue_fence *fence) { @@ -147,7 +127,6 @@ struct util_queue_fence { void util_queue_fence_init(struct util_queue_fence *fence); void util_queue_fence_destroy(struct util_queue_fence *fence); -void util_queue_fence_wait(struct util_queue_fence *fence); void util_queue_fence_signal(struct util_queue_fence *fence); /** @@ -170,6 +149,39 @@ util_queue_fence_is_signalled(struct util_queue_fence *fence) } #endif +void +_util_queue_fence_wait(struct util_queue_fence *fence); + +static inline void +util_queue_fence_wait(struct util_queue_fence *fence) +{ + if (unlikely(!util_queue_fence_is_signalled(fence))) + _util_queue_fence_wait(fence); +} + +bool +_util_queue_fence_wait_timeout(struct util_queue_fence *fence, + int64_t abs_timeout); + +/** + * Wait for the fence to be signaled with a timeout. + * + * \param fence the fence + * \param abs_timeout the absolute timeout in nanoseconds, relative to the + * clock provided by os_time_get_nano. + * + * \return true if the fence was signaled, false if the timeout occurred. + */ +static inline bool +util_queue_fence_wait_timeout(struct util_queue_fence *fence, + int64_t abs_timeout) +{ + if (util_queue_fence_is_signalled(fence)) + return true; + + return _util_queue_fence_wait_timeout(fence, abs_timeout); +} + typedef void (*util_queue_execute_func)(void *job, int thread_index); struct util_queue_job { -- cgit v1.2.3