globalmemorystatusex-cache-window.patch

diff --git a/dlls/kernelbase/memory.c b/dlls/kernelbase/memory.c
index 4f4bba9a13b7687e9f8f90dbac5a8281c4dbc3af..0f4744595077ee4b0472d14651eef3c1acddb76e 100644
--- a/dlls/kernelbase/memory.c
+++ b/dlls/kernelbase/memory.c
@@ -41,6 +41,33 @@ WINE_DEFAULT_DEBUG_CHANNEL(heap);
 WINE_DECLARE_DEBUG_CHANNEL(virtual);
 WINE_DECLARE_DEBUG_CHANNEL(globalmem);
 
+long get_globalmemorystatusex_cache_window(void)
+{
+    static long globalmemorystatusex_cache_window = -1;
+
+    if (globalmemorystatusex_cache_window == -1)
+    {
+        char str[64];
+        DWORD n;
+        memset(str, 0, sizeof(str));
+
+        // Default to 1000 ms
+        globalmemorystatusex_cache_window = 1000;
+
+        n = GetEnvironmentVariableA("WINE_GLOBALMEMORYSTATUSEX_CACHE_WINDOW", str, sizeof(str));
+
+        if (0 < n && n < sizeof(str))
+        {
+            long res = strtol(str, NULL, 10);
+            
+            if (res != LONG_MIN && res != LONG_MAX)
+            {
+                globalmemorystatusex_cache_window = res;
+            }
+        }
+    }
+    return globalmemorystatusex_cache_window;
+}
 
 /***********************************************************************
  * Virtual memory functions
@@ -1215,10 +1242,18 @@ BOOL WINAPI DECLSPEC_HOTPATCH GlobalMemoryStatusEx( MEMORYSTATUSEX *status )
         SetLastError( ERROR_INVALID_PARAMETER );
         return FALSE;
     }
-    if ((NtGetTickCount() - last_check) < 1000)
+    /* Don't bother checking the time since our last update if the cache window is 0.
+       This ensures that a cache window of '0' is guaranteed to disable the cache completely.
+       On Windows, the resolution of the GetTickCount function is limited to the resolution
+       of the system timer, which is typically in the range of 10 milliseconds to 16 milliseconds.
+    */
+    if (get_globalmemorystatusex_cache_window() > 0)
     {
-	*status = cached_status;
-	return TRUE;
+        if ((NtGetTickCount() - last_check) < get_globalmemorystatusex_cache_window())
+        {
+            *status = cached_status;
+            return TRUE;
+        }
     }
     last_check = NtGetTickCount();