* process.c (retry_fork_async_signal_safe): Use vfork() if available.

  vfork() is still faster than fork() especially when the parent
  process uses big memory.

  ruby -rbenchmark -e 'a = "a" * 1_000_000_000; puts Benchmark.measure { system("true") }'
  fork:   0.000000   0.010000   0.010000 (  0.014968)
  vfork:  0.000000   0.000000   0.000000 (  0.000912)
  on Debian sid.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47363 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 0 deletions

diff --git a/process.c b/process.c
index 89f829c846..503e73923d 100644
--- a/process.c
+++ b/process.c
@@ -50,6 +50,9 @@
 #ifdef HAVE_SYS_RESOURCE_H
 # include <sys/resource.h>
 #endif
+#ifdef HAVE_VFORK_H
+# include <vfork.h>
+#endif
 #ifdef HAVE_SYS_PARAM_H
 # include <sys/param.h>
 #endif
@@ -3291,7 +3294,11 @@ retry_fork_async_signal_safe(int *status, int *ep,
 
     while (1) {
         prefork();
+#ifdef HAVE_WORKING_VFORK
+        pid = vfork();
+#else
         pid = fork();
+#endif
         if (pid == 0) {/* fork succeed, child process */
             int ret;
             forked_child = 1;
@@ -3305,6 +3312,7 @@ retry_fork_async_signal_safe(int *status, int *ep,
             _exit(127);
 #endif
         }
+        forked_child = 0; /* for vfork(). */
         if (0 < pid) /* fork succeed, parent process */
             return pid;
         /* fork failed */