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/kernel/ke_apc.c

@@ -204,7 +204,7 @@ __declspec(dllexport) KSTATUS KeQueueUserApc(THREAD* thread,
     if (thread->State == ThreadDead)
         return STATUS_OBJECT_DEAD;
 
-    KUSER_APC* apc = (KUSER_APC*)MmAllocatePool(sizeof(KUSER_APC));
+    KUSER_APC* apc = (KUSER_APC*)MmAllocatePoolTag(sizeof(KUSER_APC), MM_POOL_TAG('a', 'p', 'c', ' '));
     if (!apc)
         return STATUS_NO_MEMORY;