[ros-diffs] [reactos] 01/01: [NTUSER] Increase desktop heap size

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=6ca6088f2c0225e98231a…

commit 6ca6088f2c0225e98231a17077f1e2fedf3c6cab
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Tue Sep 3 22:52:35 2024 +0300
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Sat Sep 7 18:47:49 2024 +0300

    [NTUSER] Increase desktop heap size
    
    Distinguish between the following 3 scenarios:
    1. Interactive Winsta0, "Winlogon" desktop: use 128 KB
    2. Interactive Winsta0, "Default" & other desktop: use 3 MB (x86) / 20
MB (x64)
    3. Non-interactive winsta: use 128 KB
    
    This is what Windows 2003 uses for the interactive desktops on x86 and what Windows 7
uses for x64. Fixes desktop heap exhaustion during testing. The previous value was 512 KB
for all desktops.
    It doesn't handle the even smaller "Disconnected" desktop, which is only
meaningful for RDP sessions and we don't use it anyway.
    See comments in the file for references.
---
 win32ss/user/ntuser/desktop.c | 44 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/win32ss/user/ntuser/desktop.c b/win32ss/user/ntuser/desktop.c
index 6ccb291ac82..ab8e87daa88 100644
--- a/win32ss/user/ntuser/desktop.c
+++ b/win32ss/user/ntuser/desktop.c
@@ -27,9 +27,26 @@ IntFreeDesktopHeap(IN PDESKTOP pdesk);
 
 /* GLOBALS *******************************************************************/
 
-/* These can be changed via CSRSS startup, these are defaults */
-DWORD gdwDesktopSectionSize = 512;
-DWORD gdwNOIOSectionSize    = 128; // A guess, for one or more of the first three system
desktops.
+/* These can be changed via registry settings.
+ * Default values (interactive desktop / non-interactive desktop):
+ * Windows 2003 x86: 3 MB / 512 KB (Disconnect: 64 KB, Winlogon: 128 KB)
+ * Windows 7 x86: 12 MB / 512 KB
+ * Windows 7 x64: 20 MB / 768 KB
+ * Windows 10 x64: 20 MB / 4 MB
+ * See:
+ * - https://dbmentors.blogspot.com/2011/09/desktop-heap-overview.html
+ * -
https://www.ibm.com/support/pages/using-microsoft-desktop-heap-monitor-dhea…
+ * - https://www.betaarchive.com/wiki/index.php?title=Microsoft_KB_Archive/184802
+ * -
https://kb.firedaemon.com/support/solutions/articles/4000086192-windows-ser…
+ * -
https://learn.microsoft.com/en-us/troubleshoot/windows-server/performance/d…
+ */
+#ifdef _WIN64
+DWORD gdwDesktopSectionSize = 20 * 1024; // 20 MB (Windows 7 style)
+#else
+DWORD gdwDesktopSectionSize = 3 * 1024; // 3 MB (Windows 2003 style)
+#endif
+DWORD gdwNOIOSectionSize    = 128;
+DWORD gdwWinlogonSectionSize = 128;
 
 /* Currently active desktop */
 PDESKTOP gpdeskInputDesktop = NULL;
@@ -2259,8 +2276,9 @@ IntPaintDesktop(HDC hDC)
 static NTSTATUS
 UserInitializeDesktop(PDESKTOP pdesk, PUNICODE_STRING DesktopName, PWINSTATION_OBJECT
pwinsta)
 {
+    static const UNICODE_STRING WinlogonDesktop =
RTL_CONSTANT_STRING(L"Winlogon");
     PVOID DesktopHeapSystemBase = NULL;
-    ULONG_PTR HeapSize = gdwDesktopSectionSize * 1024;
+    ULONG_PTR HeapSize;
     SIZE_T DesktopInfoSize;
     ULONG i;
 
@@ -2268,6 +2286,24 @@ UserInitializeDesktop(PDESKTOP pdesk, PUNICODE_STRING DesktopName,
PWINSTATION_O
 
     RtlZeroMemory(pdesk, sizeof(DESKTOP));
 
+    /* Set desktop size, based on whether the WinSta is interactive or not */
+    if (pwinsta == InputWindowStation)
+    {
+        /* Check if the Desktop is named "Winlogon" */
+        if (RtlEqualUnicodeString(DesktopName, &WinlogonDesktop, TRUE))
+        {
+            HeapSize = gdwWinlogonSectionSize * 1024;
+        }
+        else
+        {
+            HeapSize = gdwDesktopSectionSize * 1024;
+        }
+    }
+    else
+    {
+        HeapSize = gdwNOIOSectionSize * 1024;
+    }
+
     /* Link the desktop with the parent window station */
     ObReferenceObject(pwinsta);
     pdesk->rpwinstaParent = pwinsta;