delay attempt 2

README.md

@@ -31,6 +31,10 @@ When your kernel starts crashing, get the full trace with:
 
     ./run -n
 
+See also: <https://unix.stackexchange.com/questions/208260/how-to-scroll-up-after-a-kernel-panic>
+
+Then if you want your terminal back, hit `Ctrl + C, A` and type `quit`. See also: <http://stackoverflow.com/questions/14165158/how-to-switch-to-qemu-monitor-console-when-running-with-curses>
+
 1.  [Introduction](introduction.md)
 1.  [Build](build.md)
 1.  [kmod](kmod.md)

kernel_module/delay.c

@@ -7,8 +7,6 @@ Usage:
 dmesg prints an integer every second until rmmod.
 
 Since insmod returns, this Illustrates how the work queues are asynchronous.
-
-TODO: insmod not returning...
 */
 
 #include <linux/delay.h>
@@ -43,6 +41,9 @@ int init_module(void)
 
 void cleanup_module(void)
 {
+	/* This waits for the work to finish. From docstring: */
+	/* > Cancel @work and wait for its execution to finish. */
 	cancel_work_sync(&work);
+
 	destroy_workqueue(queue);
 }

kernel_module/workqueue_cheat.c

@@ -9,6 +9,10 @@ Creates a separate thread. So init_module can return, but some work will still g
 
 Can't call this just workqueue.c because there is already a built-in with that name:
 https://unix.stackexchange.com/questions/364956/how-can-insmod-fail-with-kernel-module-is-already-loaded-even-is-lsmod-does-not
+
+Bibliography:
+
+- https://www.ibm.com/developerworks/library/l-tasklets/
 */
 
 #include <linux/kernel.h>

run

@@ -33,7 +33,9 @@ qemu-system-x86_64 \
   -append "root=/dev/vda $extra_append" \
   -drive file=output/images/rootfs.ext2,if=virtio,format=raw \
   -kernel output/images/bzImage \
+  -m 128M \
   -net nic,model=virtio \
   -net user \
+  -smp 1 \
   $extra_flags \
 ;