From b6cae7e72f203862565208bb8a2e6aa82cd4c3b8 Mon Sep 17 00:00:00 2001
From: Sunderland93 <samoilov.lex@gmail.com>
Date: Tue, 6 Feb 2024 17:25:24 +0400
Subject: [PATCH] Add Zram config

---
 etc/sysctl.d/tileos.conf       |  5 +++++
 etc/udev/rules.d/30-zram.rules | 22 ++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 etc/udev/rules.d/30-zram.rules

diff --git a/etc/sysctl.d/tileos.conf b/etc/sysctl.d/tileos.conf
index eba0192..64709e1 100644
--- a/etc/sysctl.d/tileos.conf
+++ b/etc/sysctl.d/tileos.conf
@@ -68,3 +68,8 @@ vm.dirty_background_bytes = 134217728
 # The kernel flusher threads will periodically wake up and write old data out to disk.  This
 # tunable expresses the interval between those wakeups, in 100'ths of a second (Default is 500).
 vm.dirty_writeback_centisecs = 1500
+
+# The sysctl swappiness parameter determines the kernel's preference for pushing anonymous pages or page cache to disk in memory-starved situations.
+# A low value causes the kernel to prefer freeing up open files (page cache), a high value causes the kernel to try to use swap space,
+# and a value of 100 means IO cost is assumed to be equal.
+vm.swappiness = 100
diff --git a/etc/udev/rules.d/30-zram.rules b/etc/udev/rules.d/30-zram.rules
new file mode 100644
index 0000000..cf3ba27
--- /dev/null
+++ b/etc/udev/rules.d/30-zram.rules
@@ -0,0 +1,22 @@
+# Prefer to recompress only huge pages. This will result in additional memory
+# savings, but may slightly increase CPU load due to additional compression
+# overhead.
+ACTION=="add", KERNEL=="zram[0-9]*", ATTR{recomp_algorithm}="algo=lz4 priority=1", \
+  RUN+="/sbin/sh -c echo 'type=huge' > /sys/block/%k/recompress"
+
+TEST!="/dev/zram0", GOTO="zram_end"
+
+# Since ZRAM stores all pages in compressed form in RAM, we should prefer
+# preempting anonymous pages more than a page (file) cache.  Preempting file
+# pages may not be desirable because a process may want to access a file at any
+# time, whereas if it is preempted, it will cause an additional read cycle from
+# the disk.
+SYSCTL{vm.swappiness}="150"
+
+# Optimal value for games, so sets not too aggressive, but also not too weak
+# kswapd behavior, as described there:
+# https://www.reddit.com/r/linux_gaming/comments/vla9gd/comment/ie1cnrh/
+SYSCTL{vm.watermark_scale_factor}="125"
+SYSCTL{vm.watermark_boost_factor}="0"
+
+LABEL="zram_end"