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From Yann Ylavic <ylavic....@gmail.com>
Subject Re: Frequent wake-ups for mpm_event
Date Fri, 05 Aug 2016 13:19:39 GMT
Hi Luca,

On Fri, Aug 5, 2016 at 2:58 PM, Luca Toscano <toscano.luca@gmail.com> wrote:
>
> 2016-08-04 17:56 GMT+02:00 Luca Toscano <toscano.luca@gmail.com>:
>>
>> Would it be possible to avoid them adding APR_POLLSET_WAKEABLE to the
>> event_pollset flags and calling apr_pollset_wakeup right after
>> apr_skiplist_insert?

That might be possible, but there is more than apr_skiplist_insert()
to handle I'm afraid, see below.

>
>  Very high level idea: http://apaste.info/MKE

The timeout_interval also handles the listener_may_exit (and
connection_count == 0 in graceful mode), your patch seems not handle
them...

The listener_may_exit case may be easily handled in wakeup_listener
(one more apr_pollset_wakeup() there), however the connection_count
looks more complicated.

IOW, not sure something like the below would be enough...

Index: server/mpm/event/event.c
===================================================================
--- server/mpm/event/event.c    (revision 1755288)
+++ server/mpm/event/event.c    (working copy)
@@ -484,6 +484,7 @@ static void close_worker_sockets(void)
 static void wakeup_listener(void)
 {
     listener_may_exit = 1;
+    apr_pollset_wakeup(event_pollset);
     if (!listener_os_thread) {
         /* XXX there is an obscure path that this doesn't handle perfectly:
          *     right after listener thread is created but before
@@ -696,7 +697,9 @@ static apr_status_t decrement_connection_count(voi
         default:
             break;
     }
-    apr_atomic_dec32(&connection_count);
+    if (!apr_atomic_dec32(&connection_count) && listener_may_exit) {
+        apr_pollset_wakeup(event_pollset);
+    }
     return APR_SUCCESS;
 }

_

Regards,
Yann.

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