1 files changed, 13 insertions, 18 deletions

diff --git a/ext/unicorn_http/epollexclusive.h b/ext/unicorn_http/epollexclusive.h
index 677e1fe..8f4ea9a 100644
--- a/ext/unicorn_http/epollexclusive.h
+++ b/ext/unicorn_http/epollexclusive.h
@@ -64,18 +64,22 @@ static VALUE prep_readers(VALUE cls, VALUE readers)
 
 #if USE_EPOLL
 struct ep_wait {
-        struct epoll_event *events;
+        struct epoll_event event;
         rb_io_t *fptr;
-        int maxevents;
         int timeout_msec;
 };
 
 static void *do_wait(void *ptr) /* runs w/o GVL */
 {
         struct ep_wait *epw = ptr;
-
-        return (void *)(long)epoll_wait(epw->fptr->fd, epw->events,
-                                epw->maxevents, epw->timeout_msec);
+        /*
+         * Linux delivers epoll events in the order received, and using
+         * maxevents=1 ensures we pluck one item off ep->rdllist
+         * at-a-time (c.f. fs/eventpoll.c in linux.git, it's quite
+         * easy-to-understand for anybody familiar with Ruby C).
+         */
+        return (void *)(long)epoll_wait(epw->fptr->fd, &epw->event, 1,
+                                        epw->timeout_msec);
 }
 
 /* :nodoc: */
@@ -84,14 +88,10 @@ static VALUE
 get_readers(VALUE epio, VALUE ready, VALUE readers, VALUE timeout_msec)
 {
         struct ep_wait epw;
-        long i, n;
-        VALUE buf;
+        long n;
 
         Check_Type(ready, T_ARRAY);
         Check_Type(readers, T_ARRAY);
-        epw.maxevents = RARRAY_LENINT(readers);
-        buf = rb_str_buf_new(sizeof(struct epoll_event) * epw.maxevents);
-        epw.events = (struct epoll_event *)RSTRING_PTR(buf);
         epio = rb_io_get_io(epio);
         GetOpenFile(epio, epw.fptr);
 
@@ -99,17 +99,12 @@ get_readers(VALUE epio, VALUE ready, VALUE readers, VALUE timeout_msec)
         n = (long)rb_thread_call_without_gvl(do_wait, &epw, RUBY_UBF_IO, NULL);
         if (n < 0) {
                 if (errno != EINTR) rb_sys_fail("epoll_wait");
-                n = 0;
-        }
-        /* Linux delivers events in order received */
-        for (i = 0; i < n; i++) {
-                struct epoll_event *ev = &epw.events[i];
-                VALUE obj = rb_ary_entry(readers, ev->data.u64);
+        } else if (n > 0) { /* maxevents is hardcoded to 1 */
+                VALUE obj = rb_ary_entry(readers, epw.event.data.u64);
 
                 if (RTEST(obj))
                         rb_ary_push(ready, obj);
-        }
-        rb_str_resize(buf, 0);
+        } /* n == 0 : timeout */
         return Qfalse;
 }
 #endif /* USE_EPOLL */