add page cache with read-ahead and dirty writeback, file-backed and anonymous mmap with CoW, VAD-based virtual memory replacing the old user region model, PFN database with eviction and reclaim, file identity for cross-open section sharing, FAT32 path cache and per-file cluster chain cache, serial.sys for COM1 keyboard input, xHCI MSI with INTx and polled fallback, PciEnableMsiAuto, waitable input queue, KeWaitForAnyEvent, per-process thread info syscall, expanded kernel stats (PFN/PTE/VAD/file-cache/disk), pool allocation tags, async I/O user buffer locking, file flush on close, add docs.md.

code/user/tests/async_cancel/async_cancel.c

@@ -14,10 +14,35 @@ static void print(const char* s) {
     SysWriteConsole(&req);
 }
 
-// Opens file.
-static uint32_t open_file(const char* path, uint32_t* handleOut) {
-    SYS_PATH_HANDLE_REQUEST req = { SysSvFromCstr(path), handleOut };
-    return SysOpenFile(&req);
+// Opens the first available executable payload for async I/O.
+// Tests are usually launched from /apps, so a bare "system/init.exe"
+// resolves as /apps/system/init.exe and fails. Prefer the test binary itself,
+// then fall back to absolute/drive-qualified paths.
+static uint32_t open_test_file(uint32_t* handleOut, const char** pathOut) {
+    static const char* paths[] = {
+        "async_cancel.exe",
+        "/apps/async_cancel.exe",
+        "1:/apps/async_cancel.exe",
+        "0:/apps/async_cancel.exe",
+        "/system/init.exe",
+        "0:/system/init.exe",
+        "1:/system/init.exe",
+        "system/init.exe",
+    };
+
+    for (size_t i = 0; i < sizeof(paths) / sizeof(paths[0]); ++i) {
+        uint32_t h = 0;
+        SYS_PATH_HANDLE_REQUEST req = { SysSvFromCstr(paths[i]), &h };
+        uint32_t s = SysOpenFile(&req);
+        if (s == SYS_STATUS_SUCCESS) {
+            *handleOut = h;
+            if (pathOut)
+                *pathOut = paths[i];
+            return SYS_STATUS_SUCCESS;
+        }
+    }
+
+    return SYS_STATUS_NOT_FOUND;
 }
 
 // Prints u64.
@@ -46,12 +71,17 @@ int main(void) {
     uint32_t event = 0;
     uint32_t request = 0;
 
-    uint32_t s = open_file("system/init.exe", &file);
+    const char* openedPath = 0;
+    uint32_t s = open_test_file(&file, &openedPath);
     if (s != SYS_STATUS_SUCCESS) {
         print("async_cancel: open failed status="); print_u64(s); print("\n");
         SysExitProcess(1);
     }
 
+    print("async_cancel: using ");
+    print(openedPath ? openedPath : "<unknown>");
+    print("\n");
+
     s = SysCreateEvent(EVENT_AUTO_RESET, 0, &event);
     if (s != SYS_STATUS_SUCCESS) {
         print("async_cancel: event create failed status="); print_u64(s); print("\n");
@@ -90,7 +120,7 @@ int main(void) {
     print("async_cancel: cancel returned "); print_u64(cs); print("\n");
 
     while (iosb.Status == SYS_STATUS_PENDING) {
-        s = SysWaitEvent(event, 1);
+        s = SysWait(event, SYS_WAIT_FLAG_ALERTABLE);
         print("async_cancel: wait returned "); print_u64(s); print("\n");
         if (s != SYS_STATUS_SUCCESS && s != SYS_STATUS_KERNEL_APC && s != SYS_STATUS_USER_APC && s != SYS_STATUS_ALERTED)
             break;