dir: release GVL on opendir

opendir(3) is subject to the same pathological slowdowns on
slow or unreliable filesystems as open(2), so release the GVL
to avoid stalling the entire VM like we do with IO#open

* dir.c (nogvl_opendir): new function
  (opendir_without_gvl): new function
  (dir_initialize): s/opendir/&_without_gvl/
  (do_opendir): ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60830 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 23 insertions, 5 deletions

diff --git a/dir.c b/dir.c
index baeaa4db7e..e044228a5b 100644
--- a/dir.c
+++ b/dir.c
@@ -490,6 +490,24 @@ dir_s_alloc(VALUE klass)
     return obj;
 }
 
+static void *
+nogvl_opendir(void *ptr)
+{
+    const char *path = ptr;
+
+    return (void *)opendir(path);
+}
+
+static DIR *
+opendir_without_gvl(const char *path)
+{
+    union { const char *in; void *out; } u;
+
+    u.in = path;
+
+    return rb_thread_call_without_gvl(nogvl_opendir, u.out, RUBY_UBF_IO, 0);
+}
+
 /*
  *  call-seq:
  *     Dir.new( string ) -> aDir
@@ -536,18 +554,18 @@ dir_initialize(int argc, VALUE *argv, VALUE dir)
     RB_OBJ_WRITE(dir, &dp->path, Qnil);
     dp->enc = fsenc;
     path = RSTRING_PTR(dirname);
-    dp->dir = opendir(path);
+    dp->dir = opendir_without_gvl(path);
     if (dp->dir == NULL) {
 	int e = errno;
 	if (rb_gc_for_fd(e)) {
-	    dp->dir = opendir(path);
+	    dp->dir = opendir_without_gvl(path);
 	}
 #ifdef HAVE_GETATTRLIST
 	else if (e == EIO) {
 	    u_int32_t attrbuf[1];
 	    struct attrlist al = {ATTR_BIT_MAP_COUNT, 0};
 	    if (getattrlist(path, &al, attrbuf, sizeof(attrbuf), FSOPT_NOFOLLOW) == 0) {
-		dp->dir = opendir(path);
+		dp->dir = opendir_without_gvl(path);
 	    }
 	}
 #endif
@@ -1411,7 +1429,7 @@ do_opendir(const int basefd, const char *path, int flags, rb_encoding *enc,
     fd = openat(basefd, path, 0, opendir_flags);
     dirp = (fd < 0) ? NULL : fdopendir(fd);
 #else
-    dirp = opendir(path);
+    dirp = opendir_without_gvl(path);
 #endif
     if (!dirp) {
 	int e = errno;
@@ -1422,7 +1440,7 @@ do_opendir(const int basefd, const char *path, int flags, rb_encoding *enc,
 		dirp = fdopendir(fd);
 	    }
 #else
-	    dirp = opendir(path);
+	    dirp = opendir_without_gvl(path);
 #endif
 	    if (dirp) break;
 	    e = errno;