Added a comment on how to deal with directly writable memory mapped files.

There, we need to detect the modified state from the mapping, too - the
vm_page state itself might not be up to date.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@14049 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/vm/vm_page.c

@@ -169,6 +169,9 @@ vm_page_write_modified(vm_cache *cache)
 		cpu_status state = disable_interrupts();
 		acquire_spinlock(&page_lock);
 
+		// ToDo: if this is a memory mapped page, the PAGE_MODIFIED bit might
+		//	not yet have been propagated to the page state!
+
 		if (page->state == PAGE_STATE_MODIFIED) {
 			remove_page_from_queue(&page_modified_queue, page);
 			page->state = PAGE_STATE_BUSY;