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diff src/event/modules/ngx_epoll_module.c @ 6635:6acaa638fa07

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Events: support for EPOLLEXCLUSIVE. This flag appeared in Linux 4.5 and is useful for avoiding thundering herd problem. The current Linux kernel implementation walks the list of exclusive waiters, and queues an event to each epfd, until it finds the first waiter that has threads blocked on it via epoll_wait().
author Valentin Bartenev <vbart@nginx.com>
date Fri, 15 Jul 2016 15:18:57 +0300
parents 18f6120e3b7a
children 75dbab4ea930
line wrap: on
line diff
--- a/src/event/modules/ngx_epoll_module.c
+++ b/src/event/modules/ngx_epoll_module.c
@@ -27,6 +27,7 @@
 
 #define EPOLLRDHUP     0x2000
 
+#define EPOLLEXCLUSIVE 0x10000000
 #define EPOLLONESHOT   0x40000000
 #define EPOLLET        0x80000000
 
@@ -610,6 +611,12 @@ ngx_epoll_add_event(ngx_event_t *ev, ngx
         op = EPOLL_CTL_ADD;
     }
 
+#if (NGX_HAVE_EPOLLEXCLUSIVE && NGX_HAVE_EPOLLRDHUP)
+    if (flags & NGX_EXCLUSIVE_EVENT) {
+        events &= ~EPOLLRDHUP;
+    }
+#endif
+
     ee.events = events | (uint32_t) flags;
     ee.data.ptr = (void *) ((uintptr_t) c | ev->instance);