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*** empty log message ***

master
Marc Alexander Lehmann 8 years ago
parent
commit
a7dbe8f365
1 changed files with 9 additions and 6 deletions
  1. +9
    -6
      ev.c

+ 9
- 6
ev.c View File

@ -561,7 +561,6 @@ struct signalfd_siginfo
#define ECB_C99 (__STDC_VERSION__ >= 199901L)
#define ECB_C11 (__STDC_VERSION__ >= 201112L)
#define ECB_CPP (__cplusplus+0)
#define ECB_CPP98 (__cplusplus >= 199711L)
#define ECB_CPP11 (__cplusplus >= 201103L)
/*****************************************************************************/
@ -616,10 +615,10 @@ struct signalfd_siginfo
#ifndef ECB_MEMORY_FENCE
#if ECB_GCC_VERSION(4,7)
/* see comment below about the C11 memory model. in short - avoid */
/* see comment below (stdatomic.h) about the C11 memory model. */
#define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST)
#elif defined __clang && __has_feature (cxx_atomic)
/* see above */
/* see comment below (stdatomic.h) about the C11 memory model. */
#define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)
#elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__
#define ECB_MEMORY_FENCE __sync_synchronize ()
@ -646,8 +645,12 @@ struct signalfd_siginfo
/* we assume that these memory fences work on all variables/all memory accesses, */
/* not just C11 atomics and atomic accesses */
#include <stdatomic.h>
/* unfortunately, the C11 memory model seems to be very limited, and unable to express */
/* simple barrier semantics. That means we need to take out thor's hammer. */
/* Unfortunately, neither gcc 4.7 nor clang 3.1 generate any instructions for */
/* any fence other than seq_cst, which isn't very efficient for us. */
/* Why that is, we don't know - either the C11 memory model is quite useless */
/* for most usages, or gcc and clang have a bug */
/* I *currently* lean towards the latter, and inefficiently implement */
/* all three of ecb's fences as a seq_cst fence */
#define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst)
#endif
#endif
@ -3137,7 +3140,7 @@ ev_run (EV_P_ int flags)
pipe_write_wanted = 0; /* just an optimisation, no fence needed */
MEMORY_FENCE_ACQUIRE;
ECB_MEMORY_FENCE_ACQUIRE;
if (pipe_write_skipped)
{
assert (("libev: pipe_w not active, but pipe not written", ev_is_active (&pipe_w)));


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