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From: Ken Brown <kbrown@cornell.edu>
To: cygwin-patches@cygwin.com
Subject: [PATCH 09/12] Cygwin: fhandler_fifo::take_ownership: don't set event unnecessarily
Date: Thu, 16 Jul 2020 12:19:12 -0400	[thread overview]
Message-ID: <20200716161915.16994-10-kbrown@cornell.edu> (raw)
In-Reply-To: <20200716161915.16994-1-kbrown@cornell.edu>

Don't set update_needed_evt if there's currently no owner.  This will
cause unnecessary churn once I'm the owner and am listening for
connections.
---
 winsup/cygwin/fhandler_fifo.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc
index b6e172ddc..fd1695f40 100644
--- a/winsup/cygwin/fhandler_fifo.cc
+++ b/winsup/cygwin/fhandler_fifo.cc
@@ -1186,8 +1186,11 @@ fhandler_fifo::take_ownership ()
       return;
     }
   set_pending_owner (me);
+  /* Wake up my fifo_reader_thread. */
   owner_needed ();
-  SetEvent (update_needed_evt);
+  if (get_owner ())
+    /* Wake up owner's fifo_reader_thread. */
+    SetEvent (update_needed_evt);
   owner_unlock ();
   /* The reader threads should now do the transfer.  */
   WaitForSingleObject (owner_found_evt, INFINITE);
-- 
2.27.0


  parent reply	other threads:[~2020-07-16 16:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 16:19 [PATCH 00/12] FIFO: fix multiple reader support Ken Brown
2020-07-16 16:19 ` [PATCH 01/12] Cygwin: FIFO: fix problems finding new owner Ken Brown
2020-07-16 16:19 ` [PATCH 02/12] Cygwin: FIFO: keep a writer count in shared memory Ken Brown
2020-07-16 16:19 ` [PATCH 03/12] Cygwin: fhandler_fifo::hit_eof: improve reliability Ken Brown
2020-07-16 16:19 ` [PATCH 04/12] Cygwin: FIFO: reduce I/O interleaving Ken Brown
2020-07-16 16:19 ` [PATCH 05/12] Cygwin: FIFO: improve taking ownership in fifo_reader_thread Ken Brown
2020-07-16 16:19 ` [PATCH 06/12] Cygwin: FIFO: fix indentation Ken Brown
2020-07-16 16:19 ` [PATCH 07/12] Cygwin: FIFO: make certain errors non-fatal Ken Brown
2020-07-16 16:19 ` [PATCH 08/12] Cygwin: FIFO: add missing lock Ken Brown
2020-07-16 16:19 ` Ken Brown [this message]
2020-07-16 16:19 ` [PATCH 10/12] Cygwin: FIFO: allow take_ownership to be interrupted Ken Brown
2020-07-16 16:19 ` [PATCH 11/12] Cygwin: FIFO: clean up Ken Brown
2020-07-16 16:19 ` [PATCH 12/12] Cygwin: FIFO: update commentary Ken Brown
2020-07-16 19:57 ` [PATCH 00/12] FIFO: fix multiple reader support Corinna Vinschen

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