live init: optionally specify RAM % to use in the 'toram' parameter

toram=
  Generic syntax: toram=type[,memperc]
  - type: string value; os,core,all,none
  - memperc: integer value, percentage RAM to reserve for liveslak

You can use a 'memperc' value for the 'toram' parameter to change
the percentage RAM used by liveslak, which is 50% of all available RAM
for normal operation.
For instance when you have 128 GB of RAM, you can specify a much lower
percentage to be reserved for liveslak. RAM will specifically be used
if you run liveslak without persistence, which means that any changes are
accumulating in RAM instead of on-disk.
Example:
Give liveslak ~6 GB (5%) to run the OS on a computer with 128 GB of RAM:
  'toram=none,5'

1 files changed, 21 insertions, 5 deletions

diff --git a/liveinit.tpl b/liveinit.tpl
index d00650d..7194229 100644
--- a/liveinit.tpl
+++ b/liveinit.tpl
@@ -274,13 +274,29 @@ for ARG in $(cat /proc/cmdline); do
       VIRGIN=1 # prevent writes to disk since we are supposed to run from RAM
     ;;
     toram=*)
+      # Generic syntax: toram=type[,memperc]
+      #   type: string value; os,core,all,none
+      #   memperc: integer value, percentage RAM to reserve for liveslak
+      # You can use this parameter to change the percentage RAM
+      # used by liveslak, which is 50% for normal operation.
+      # For instance when you have an insane amount of RAM, you can specify
+      # a much lower percentage to be reserved for liveslak:
+      #   toram=none,12
       TORAM=1
-      if [ "$(echo $ARG | cut -f2 -d=)" = "os" ]; then
+      TRTYPE="$(echo $ARG |cut -f2 -d= |cut -f1 -d,)"
+      if [ "$TRTYPE" = "os" ]; then
         VIRGIN=0 # load OS modules into RAM, write persistent data to disk
-      elif [ "$(echo $ARG | cut -f2 -d=)" = "core" ]; then
+      elif [ "$TRTYPE" = "core" ]; then
         CORE2RAM=1 # load Core OS modules into RAM
-      elif [ "$(echo $ARG | cut -f2 -d=)" = "all" ]; then
+      elif [ "$TRTYPE" = "all" ]; then
         VIRGIN=1 # prevent writes to disk since we are supposed to run from RAM
+      elif [ "$TRTYPE" = "none" ]; then
+        TORAM=0 # we only want to change the percentage reserved memory
+      fi
+      RAMSIZE="$(echo $ARG |cut -f2 -d= |cut -f2 -d,)"
+      if [ "$RAMSIZE" = "$TRTYPE" ]; then
+        # memperc was not supplied on commandline:
+        unset RAMSIZE
       fi
     ;;
     tweaks=*)
@@ -688,9 +704,9 @@ if [ "$RESCUE" = "" ]; then
   # We need a mounted filesystem here to be able to do a switch_root later,
   # so we create one in RAM:
   if [ $TORAM -eq 1 ]; then
-    RAMSIZE=90%  # need to be able to load the entire OS in RAM
+    RAMSIZE="${RAMSIZE:-90}%"  # 90% by default to load the entire OS in RAM
   else
-    RAMSIZE=50%  # the default value.
+    RAMSIZE="${RAMSIZE:-50}%"  # 50% is the default value.
   fi
   mount -t tmpfs -o defaults,size=${RAMSIZE} none /mnt