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temporary fence hack

master
Marc Alexander Lehmann 10 years ago
parent
commit
a1a66b9b1c
2 changed files with 71 additions and 25 deletions
  1. +1
    -0
      Changes
  2. +70
    -25
      ev.c

+ 1
- 0
Changes View File

@ -2,6 +2,7 @@ Revision history for libev, a high-performance and full-featured event loop.
TODO: ev_loop_wakeup
TODO: EV_MF_ACQ / EV_MF_REL (e.g. __sync_synchronize)
4.10
- fix a race where the workaround against the epoll fork bugs
caused signals to not be handled anymore.


+ 70
- 25
ev.c View File

@ -494,6 +494,45 @@ struct signalfd_siginfo
#define ecb_inline static
#endif
#ifndef ECB_MEMORY_FENCE
#if ECB_GCC_VERSION(2,5)
#if __x86
#define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE /* better be safe than sorry */
#elif __amd64
#define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
#define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory")
#define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence")
#endif
#endif
#endif
#ifndef ECB_MEMORY_FENCE
#if ECB_GCC_VERSION(4,4)
#define ECB_MEMORY_FENCE __sync_synchronize ()
#define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); })
#define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); })
#elif _MSC_VER >= 1400
#define ECB_MEMORY_FENCE do { } while (0)
#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
#elif defined(_WIN32) && defined(MemoryBarrier)
#define ECB_MEMORY_FENCE MemoryBarrier ()
#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
#endif
#endif
#ifndef ECB_MEMORY_FENCE
#include <pthread.h>
static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
#define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
#endif
#if ECB_GCC_VERSION(3,1)
#define ecb_attribute(attrlist) __attribute__(attrlist)
#define ecb_is_constant(expr) __builtin_constant_p (expr)
@ -1422,39 +1461,43 @@ evpipe_init (EV_P)
inline_speed void
evpipe_write (EV_P_ EV_ATOMIC_T *flag)
{
if (!*flag)
{
*flag = 1;
if (expect_true (*flag))
return;
pipe_write_skipped = 1;
*flag = 1;
if (pipe_write_wanted)
{
int old_errno;
ECB_MEMORY_FENCE_RELEASE;
pipe_write_skipped = 0;
pipe_write_skipped = 1;
ECB_MEMORY_FENCE;
if (pipe_write_wanted)
{
int old_errno;
old_errno = errno; /* save errno because write will clobber it */
pipe_write_skipped = 0; /* optimisation only */
old_errno = errno; /* save errno because write will clobber it */
#if EV_USE_EVENTFD
if (evfd >= 0)
{
uint64_t counter = 1;
write (evfd, &counter, sizeof (uint64_t));
}
else
if (evfd >= 0)
{
uint64_t counter = 1;
write (evfd, &counter, sizeof (uint64_t));
}
else
#endif
{
/* win32 people keep sending patches that change this write() to send() */
/* and then run away. but send() is wrong, it wants a socket handle on win32 */
/* so when you think this write should be a send instead, please find out */
/* where your send() is from - it's definitely not the microsoft send, and */
/* tell me. thank you. */
write (evpipe [1], &(evpipe [1]), 1);
}
errno = old_errno;
{
/* win32 people keep sending patches that change this write() to send() */
/* and then run away. but send() is wrong, it wants a socket handle on win32 */
/* so when you think this write should be a send instead, please find out */
/* where your send() is from - it's definitely not the microsoft send, and */
/* tell me. thank you. */
write (evpipe [1], &(evpipe [1]), 1);
}
errno = old_errno;
}
}
@ -2575,6 +2618,8 @@ ev_run (EV_P_ int flags)
/* from now on, we want a pipe-wake-up */
pipe_write_wanted = 1;
ECB_MEMORY_FENCE;
if (expect_true (!(flags & EVRUN_NOWAIT || idleall || !activecnt || pipe_write_skipped)))
{
waittime = MAX_BLOCKTIME;


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