ecore-wayland: (version2) Fix monitoring ECORE_FD_WRITE defaultly on wayland display fd lead to 100% cpu usage

[Alex Wu]

Hi all,
To fix the regression reported at
http://trac.enlightenment.org/e/ticket/1993, I cooked the version 2 of
this patch. Please checkout it out.
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From e4ff96104075c972b24752e6799ac88acceccd48 Mon Sep 17 00:00:00 2001
From: Alex Wu <zhiwen.wu at linux.intel.com>
Date: Mon, 17 Dec 2012 11:05:11 +0800
Subject: [PATCH] ecore-wayland: (version 2)Fix monitoring ECORE_FD_WRITE
 defaultly on wayland                display fd lead to 100%
 cpu usage

In ecore_wl_init(), adding wayland display fd with ECORE_FD_WRITE
flag make CPU usage 100%. The proper way to monitor the ECORE_FD_WRITE
is when the wl_display_flush() return value < 0 and errno == EAGAIN.
And if wl_display_flush() return, we remove ECORE_FD_WRITE flag from
the display fd.

Change from v1:
Add idle enterer destroy code into _ecore_wl_shutdown() to avoid
using freed wl_display.
---
 trunk/efl/src/lib/ecore_wayland/Ecore_Wayland.h |    1 +
 trunk/efl/src/lib/ecore_wayland/ecore_wl.c      |   40 +++++++++++++++++++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/trunk/efl/src/lib/ecore_wayland/Ecore_Wayland.h b/trunk/efl/src/lib/ecore_wayland/Ecore_Wayland.h
index 5281c6f..eadfc14 100644
--- a/trunk/efl/src/lib/ecore_wayland/Ecore_Wayland.h
+++ b/trunk/efl/src/lib/ecore_wayland/Ecore_Wayland.h
@@ -87,6 +87,7 @@ struct _Ecore_Wl_Display
    unsigned int mask;
    unsigned int serial;
    Ecore_Fd_Handler *fd_hdl;
+   Ecore_Idle_Enterer *idle_enterer;
 
    struct wl_list inputs;
    struct wl_list outputs;
diff --git a/trunk/efl/src/lib/ecore_wayland/ecore_wl.c b/trunk/efl/src/lib/ecore_wayland/ecore_wl.c
index 7f06a1d..3e5bc8f 100644
--- a/trunk/efl/src/lib/ecore_wayland/ecore_wl.c
+++ b/trunk/efl/src/lib/ecore_wayland/ecore_wl.c
@@ -7,6 +7,7 @@
 
 /* local function prototypes */
 static Eina_Bool _ecore_wl_shutdown(Eina_Bool close);
+static Eina_Bool _ecore_wl_cb_idle_enterer(void *data);
 static Eina_Bool _ecore_wl_cb_handle_data(void *data, Ecore_Fd_Handler *hdl);
 static void _ecore_wl_cb_handle_global(void *data, struct wl_registry *registry, unsigned int id, const char *interface, unsigned int version EINA_UNUSED);
 static Eina_Bool _ecore_wl_xkb_init(Ecore_Wl_Display *ewd);
@@ -138,10 +139,13 @@ ecore_wl_init(const char *name)
 
    _ecore_wl_disp->fd_hdl =
      ecore_main_fd_handler_add(_ecore_wl_disp->fd,
-                               ECORE_FD_READ | ECORE_FD_WRITE,
+                               ECORE_FD_READ,
                                _ecore_wl_cb_handle_data, _ecore_wl_disp,
                                NULL, NULL);
 
+   _ecore_wl_disp->idle_enterer =
+     ecore_idle_enterer_add(_ecore_wl_cb_idle_enterer, _ecore_wl_disp);
+
    wl_list_init(&_ecore_wl_disp->inputs);
    wl_list_init(&_ecore_wl_disp->outputs);
 
@@ -356,6 +360,8 @@ _ecore_wl_shutdown(Eina_Bool close)
 
    if (_ecore_wl_disp->fd_hdl)
      ecore_main_fd_handler_del(_ecore_wl_disp->fd_hdl);
+   if (_ecore_wl_disp->idle_enterer)
+      ecore_idle_enterer_del(_ecore_wl_disp->idle_enterer);
 
    if (close)
      {
@@ -397,9 +403,31 @@ _ecore_wl_shutdown(Eina_Bool close)
 }
 
 static Eina_Bool
+_ecore_wl_cb_idle_enterer(void *data)
+{
+   Ecore_Wl_Display *ewd;
+   int ret;
+
+   if (!(ewd = data)) return ECORE_CALLBACK_RENEW;
+
+   ret = wl_display_flush(ewd->wl.display);
+   if (ret < 0 && errno == EAGAIN)
+     {
+        ecore_main_fd_handler_active_set(ewd->fd_hdl, ECORE_FD_READ | ECORE_FD_WRITE);
+     }
+   else if (ret < 0)
+     {
+      /* FIXME: need do error processing? */
+     }
+
+   return ECORE_CALLBACK_RENEW;
+}
+
+static Eina_Bool
 _ecore_wl_cb_handle_data(void *data, Ecore_Fd_Handler *hdl)
 {
    Ecore_Wl_Display *ewd;
+   int ret;
 
    /* LOGFN(__FILE__, __LINE__, __FUNCTION__); */
 
@@ -412,7 +440,15 @@ _ecore_wl_cb_handle_data(void *data, Ecore_Fd_Handler *hdl)
    if (ecore_main_fd_handler_active_get(hdl, ECORE_FD_READ))
      wl_display_dispatch(ewd->wl.display);
    else if (ecore_main_fd_handler_active_get(hdl, ECORE_FD_WRITE))
-     wl_display_flush(ewd->wl.display);
+     {
+        ret = wl_display_flush(ewd->wl.display);
+        if (ret == 0)
+          ecore_main_fd_handler_active_set(hdl, ECORE_FD_READ);
+        else if (ret == -1 && errno != EAGAIN)
+          {
+            /* FIXME: need do error processing? */
+          }
+     }
 
    return ECORE_CALLBACK_RENEW;
 }
-- 
1.7.9.5