[Guile-commits] 09/17: Simplify critical section implementation

[Andy Wingo]

wingo pushed a commit to branch master
in repository guile.

commit b410667e6434ef62a9c050dc4cbbff6f32a0c656
Author: Andy Wingo <address@hidden>
Date:   Tue Nov 1 22:48:19 2016 +0100

    Simplify critical section implementation
    
    * libguile/async.h (SCM_CRITICAL_SECTION_START)
      (SCM_CRITICAL_SECTION_END): Define in just one way.
    * libguile/async.c (critical_section_mutex): New static variable.
      (scm_critical_section_start, scm_critical_section_end): Inline
      internal body of critical section gates.
      (scm_init_async): Init critical_section_mutex.
    * libguile/threads.c (scm_threads_prehistory): Don't declare critical
      section mutex here.
---
 libguile/async.c   |   16 ++++++++++------
 libguile/async.h   |   32 ++------------------------------
 libguile/threads.c |    6 ------
 3 files changed, 12 insertions(+), 42 deletions(-)

diff --git a/libguile/async.c b/libguile/async.c
index aa4f508..d7b266b 100644
--- a/libguile/async.c
+++ b/libguile/async.c
@@ -299,21 +299,23 @@ scm_c_call_with_unblocked_asyncs (void *(*proc) (void 
*data), void *data)
 }
 
 
-/* These are function variants of the same-named macros (uppercase) for use
-   outside of libguile.  This is so that `SCM_I_CURRENT_THREAD', which may
-   reside in TLS, is not accessed from outside of libguile.  It thus allows
-   libguile to be built with the "local-dynamic" TLS model.  */
+static scm_i_pthread_mutex_t critical_section_mutex;
 
 void
 scm_critical_section_start (void)
 {
-  SCM_CRITICAL_SECTION_START;
+  scm_i_pthread_mutex_lock (&critical_section_mutex);
+  SCM_I_CURRENT_THREAD->block_asyncs++;
+  SCM_I_CURRENT_THREAD->critical_section_level++;
 }
 
 void
 scm_critical_section_end (void)
 {
-  SCM_CRITICAL_SECTION_END;
+  SCM_I_CURRENT_THREAD->critical_section_level--;
+  SCM_I_CURRENT_THREAD->block_asyncs--;
+  scm_i_pthread_mutex_unlock (&critical_section_mutex);
+  scm_async_tick ();
 }
 
 
@@ -321,6 +323,8 @@ scm_critical_section_end (void)
 void
 scm_init_async ()
 {
+  scm_i_pthread_mutex_init (&critical_section_mutex,
+                           scm_i_pthread_mutexattr_recursive);
 #include "libguile/async.x"
 }
 
diff --git a/libguile/async.h b/libguile/async.h
index 578e901..b709894 100644
--- a/libguile/async.h
+++ b/libguile/async.h
@@ -48,39 +48,11 @@ SCM_API void scm_dynwind_unblock_asyncs (void);
 
 /* Critical sections */
 
-/* XXX - every critical section needs to be examined whether the
-   requirements for SCM_CRITICAL_SECTION_START/END are fulfilled.  See
-   the manual.
-*/
-
-/* Defined in threads.c. */
-SCM_INTERNAL scm_i_pthread_mutex_t scm_i_critical_section_mutex;
-
 SCM_API void scm_critical_section_start (void);
 SCM_API void scm_critical_section_end (void);
 
-#ifdef BUILDING_LIBGUILE
-
-# define SCM_CRITICAL_SECTION_START                            \
-  do {                                                         \
-    scm_i_pthread_mutex_lock (&scm_i_critical_section_mutex);  \
-    SCM_I_CURRENT_THREAD->block_asyncs++;                      \
-    SCM_I_CURRENT_THREAD->critical_section_level++;            \
-  } while (0)
-# define SCM_CRITICAL_SECTION_END                              \
-  do {                                                         \
-    SCM_I_CURRENT_THREAD->critical_section_level--;            \
-    SCM_I_CURRENT_THREAD->block_asyncs--;                      \
-    scm_i_pthread_mutex_unlock (&scm_i_critical_section_mutex); \
-    scm_async_tick ();                                         \
-  } while (0)
-
-#else /* !BUILDING_LIBGUILE */
-
-# define SCM_CRITICAL_SECTION_START  scm_critical_section_start ()
-# define SCM_CRITICAL_SECTION_END    scm_critical_section_end ()
-
-#endif /* !BUILDING_LIBGUILE */
+#define SCM_CRITICAL_SECTION_START  scm_critical_section_start ()
+#define SCM_CRITICAL_SECTION_END    scm_critical_section_end ()
 
 SCM_INTERNAL void scm_init_async (void);
 
diff --git a/libguile/threads.c b/libguile/threads.c
index b2b3528..c27a7ea 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -1939,10 +1939,6 @@ static scm_i_pthread_cond_t wake_up_cond;
 static int threads_initialized_p = 0;
 
 
-/* This mutex is used by SCM_CRITICAL_SECTION_START/END.
- */
-scm_i_pthread_mutex_t scm_i_critical_section_mutex;
-
 static SCM dynwind_critical_section_mutex;
 
 void
@@ -1971,8 +1967,6 @@ scm_threads_prehistory (void *base)
                             PTHREAD_MUTEX_RECURSIVE);
 #endif
 
-  scm_i_pthread_mutex_init (&scm_i_critical_section_mutex,
-                           scm_i_pthread_mutexattr_recursive);
   scm_i_pthread_mutex_init (&scm_i_misc_mutex, NULL);
   scm_i_pthread_cond_init (&wake_up_cond, NULL);