From 937051217618df77c202b367696a657354aa8a78 Mon Sep 17 00:00:00 2001
From: Ciro Santilli <ciro.santilli@gmail.com>
Date: Mon, 15 May 2017 08:18:51 +0100
Subject: [PATCH] delay attempt 2

---
 README.md                       | 4 ++++
 kernel_module/delay.c           | 5 +++--
 kernel_module/workqueue_cheat.c | 4 ++++
 run                             | 2 ++
 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 6b559fab..d6033e83 100644
--- a/README.md
+++ b/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)
diff --git a/kernel_module/delay.c b/kernel_module/delay.c
index ebf58897..90ac0f44 100644
--- a/kernel_module/delay.c
+++ b/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);
 }
diff --git a/kernel_module/workqueue_cheat.c b/kernel_module/workqueue_cheat.c
index 39553f60..36e20748 100644
--- a/kernel_module/workqueue_cheat.c
+++ b/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>
diff --git a/run b/run
index dbc2b1fb..f447666b 100755
--- a/run
+++ b/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 \
 ;