From dd3e8b9ec62cec77cea5ff9bdda64084a9e436d0 Mon Sep 17 00:00:00 2001
From: seantywork <seantywork@gmail.com>
Date: Mon, 20 Oct 2025 14:07:21 +0900
Subject: [PATCH] krcu cmap relocated to medium

---
 krcu-cmap/{README.md => 2509-29.xyz.md} | 44 ++++---------------------
 1 file changed, 7 insertions(+), 37 deletions(-)
 rename krcu-cmap/{README.md => 2509-29.xyz.md} (73%)

diff --git a/krcu-cmap/README.md b/krcu-cmap/2509-29.xyz.md
similarity index 73%
rename from krcu-cmap/README.md
rename to krcu-cmap/2509-29.xyz.md
index 489fe5a..6a0b838 100644
--- a/krcu-cmap/README.md
+++ b/krcu-cmap/2509-29.xyz.md
@@ -3,25 +3,7 @@
 - source: [linuxyz/krcu-cmap](https://github.com/seantywork/linuxyz/tree/main/krcu-cmap)
 - date: 2509-24
 
-In user space on Linux, we can utilize `pthread_rwlock` to design a read-heavy data structure.
-
-A similar thing in the Linux kernel space is called `rcu`, a shorthand for "read, copy, update".
-
-Full documentation on it is [here](https://www.kernel.org/doc/html/next/RCU/whatisRCU.html)
-
-However, with `pthread_rwlock` in mind, it could be a little bit puzzling (at least it was for me) \
-to grasp the proper use and order of apis unlike in the case of \
-pthread_rwlock where you simply call *_rdlock on read and *_wrlock \
-on update
-
-Reading the docs wasn't enough for me.
-
-So I did the thing when I'm confused about the concept of multi-threading \
-and syncing mechanism: \
-**Building a concurrent map example!**
-
-Here, this is the outlay of this example.
-
+# 01
 
 ```shell
 # a regular old concurrent map...
@@ -43,8 +25,7 @@ concurrent_map
 |     |
 ---------------
 ```
-However, in this case, our `node` data structure here \
-contains the magic element
+# 02
 
 ```c
 struct node {
@@ -55,13 +36,7 @@ struct node {
 };
 ```
 
-With all these, our scenario will flow like the diagram below.
-The critical part to look for (in my opinion) is \
-`delete all nodes` part from writer thread.
-
-If this `rcu` thing cannot guarantee the basic functionality\
-we expect from things such as `pthread_rwlock`, then this part\
-will cause the GD kernel panic.
+# 03
 
 ```shell
 
@@ -84,21 +59,19 @@ will cause the GD kernel panic.
 --------------------------------------------------------------
 ```
 
-Now, let's compile the kernel module.
+# 04
 
 ```shell
 $ make
 ```
-Pop up another terminal, and use `dmesg` command to follow.
+ # 05
 
 ```shell
 
 $ sudo dmesg -wH
 ```
 
-Load the kernel module with `insmod` command. \
-As soon as you do this, `dmesg` will output the result \
-described in the diagram above.
+# 06
 
 ```shell
 $ sudo insmod rcucmap.ko
@@ -178,10 +151,7 @@ $ sudo insmod rcucmap.ko
 
 ```
 
-As you can see, the program is working as expected and (thank god) \
-there is no kernel panic!
-
-Pleased, unload the kernel module.
+# 07
 
 ```shell
 $ sudo rmmod rcucmap
-- 
2.43.0