From a2ec09bc205ecbf746f9cc245054c24c50b6832a Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Wed, 16 Jan 2019 17:47:18 +0100
Subject: [PATCH] Allow the scheduler to unblock the current process.

It's a bit confusing that the "current" process is not actually running
while we're inside the scheduler. Perhaps the scheduler should redirect
"current" to its own dummy Process. I'm not sure.

Regardless, this patch improves responsiveness by allowing the scheduler
to unblock a process right after it calls select() in case it already has
a pending wakeup request.
---
 Kernel/.bochsrc                  |  2 +-
 Kernel/Process.cpp               |  3 ++-
 WindowServer/WSWindowManager.cpp | 14 ++++++++++++--
 WindowServer/WSWindowManager.h   |  1 +
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/Kernel/.bochsrc b/Kernel/.bochsrc
index a061866f39..a06fedbe30 100644
--- a/Kernel/.bochsrc
+++ b/Kernel/.bochsrc
@@ -26,7 +26,7 @@ optramimage2: file=none
 optramimage3: file=none
 optramimage4: file=none
 pci: enabled=1, chipset=i440fx
-vga: extension=vbe, update_freq=25, realtime=1
+vga: extension=vbe, update_freq=60, realtime=0
 cpu: count=1, ips=4000000, model=bx_generic, reset_on_triple_fault=1, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
 cpuid: level=6, stepping=3, model=3, family=6, vendor_string="GenuineIntel", brand_string="              Intel(R) Pentium(R) 4 CPU        "
 cpuid: mmx=true, apic=xapic, simd=sse2, sse4a=false, misaligned_sse=false, sep=true
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 8939fa6b35..0a24ebebfa 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -1551,7 +1551,8 @@ pid_t Process::sys$waitpid(pid_t waitee, int* wstatus, int options)
 void Process::unblock()
 {
     if (current == this) {
-        kprintf("ignoring unblock() on current, %s(%u) {%s}\n", name().characters(), pid(), toString(state()));
+        system.nblocked--;
+        m_state = Process::Running;
         return;
     }
     ASSERT(m_state != Process::Runnable && m_state != Process::Running);
diff --git a/WindowServer/WSWindowManager.cpp b/WindowServer/WSWindowManager.cpp
index 710eefea55..1f0162e20b 100644
--- a/WindowServer/WSWindowManager.cpp
+++ b/WindowServer/WSWindowManager.cpp
@@ -10,6 +10,7 @@
 #include <AK/StdLibExtras.h>
 
 //#define DEBUG_FLUSH_YELLOW
+//#define DEBUG_COUNTERS
 
 static const int windowTitleBarHeight = 16;
 
@@ -109,6 +110,10 @@ WSWindowManager::WSWindowManager()
     : m_framebuffer(WSFrameBuffer::the())
     , m_screen_rect(m_framebuffer.rect())
 {
+#ifndef DEBUG_COUNTERS
+    (void)m_recompose_count;
+    (void)m_flush_count;
+#endif
     auto size = m_screen_rect.size();
     m_front_bitmap = GraphicsBitmap::create_wrapper(size, m_framebuffer.scanline(0));
     auto* region = current->allocate_region(LinearAddress(), size.width() * size.height() * sizeof(RGBA32), "BackBitmap", true, true, true);
@@ -266,9 +271,10 @@ void WSWindowManager::processMouseEvent(MouseEvent& event)
 void WSWindowManager::compose()
 {
     auto invalidated_rects = move(m_invalidated_rects);
-    printf("[WM] compose #%u (%u rects)\n", ++m_recompose_count, invalidated_rects.size());
-
+#ifdef DEBUG_COUNTERS
+    dbgprintf("[WM] compose #%u (%u rects)\n", ++m_recompose_count, invalidated_rects.size());
     dbgprintf("kmalloc stats: alloc:%u free:%u eternal:%u\n", sum_alloc, sum_free, kmalloc_sum_eternal);
+#endif
 
     auto any_window_contains_rect = [this] (const Rect& r) {
         for (auto* window = m_windows_in_order.head(); window; window = window->next()) {
@@ -387,6 +393,10 @@ void WSWindowManager::flush(const Rect& a_rect)
 {
     auto rect = Rect::intersection(a_rect, m_screen_rect);
 
+#ifdef DEBUG_COUNTERS
+    dbgprintf("[WM] flush #%u (%d,%d %dx%d)\n", ++m_flush_count, rect.x(), rect.y(), rect.width(), rect.height());
+#endif
+
     RGBA32* front_ptr = m_front_bitmap->scanline(rect.y()) + rect.x();
     const RGBA32* back_ptr = m_back_bitmap->scanline(rect.y()) + rect.x();
     size_t pitch = m_back_bitmap->pitch();
diff --git a/WindowServer/WSWindowManager.h b/WindowServer/WSWindowManager.h
index b6bf211ac2..58be90b8d6 100644
--- a/WindowServer/WSWindowManager.h
+++ b/WindowServer/WSWindowManager.h
@@ -77,6 +77,7 @@ private:
     Rect m_last_cursor_rect;
 
     unsigned m_recompose_count { 0 };
+    unsigned m_flush_count { 0 };
 
     RetainPtr<GraphicsBitmap> m_front_bitmap;
     RetainPtr<GraphicsBitmap> m_back_bitmap;