init: Change extra_free_kbytes.sh to add margin relative to the default watermark level
extra_free_kbytes.sh accepts a parameter representing the number of KB
to add to low and high watermarks. It adds this margin to the current
watermark levels, however this is not how /proc/sys/vm/extra_free_kbytes
knob that it replaces used to work. The old knob would add the margin
relative to the original and not the current level of the watermarks.
Change extra_free_kbytes.sh to add the specified margin to the original
watermark levels to act as correct replacement of the old knob.
Bug: 242837506
Fixes: 642048d96994 ("init: Add extra_free_kbytes.sh script to adjust watermark_scale_factor")
Test: repeatedly run 'setprop sys.sysctl.extra_free_kbytes 30375'
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I8af603ba00bd4fb8182b80b3c0969fa96cdd7311
diff --git a/init/extra_free_kbytes.sh b/init/extra_free_kbytes.sh
index aeaa912..a0141be 100755
--- a/init/extra_free_kbytes.sh
+++ b/init/extra_free_kbytes.sh
@@ -77,7 +77,19 @@
exit
fi
-watermark_scale=`cat /proc/sys/vm/watermark_scale_factor`
+# record the original watermark_scale_factor value
+watermark_scale=$(getprop "ro.kernel.watermark_scale_factor")
+if [ -z "$watermark_scale" ]
+then
+ watermark_scale=$(cat /proc/sys/vm/watermark_scale_factor)
+ setprop "ro.kernel.watermark_scale_factor" "$watermark_scale"
+ # On older distributions with no policies configured setprop may fail.
+ # If that happens, use the kernel default of 10.
+ if [ -z $(getprop "ro.kernel.watermark_scale_factor") ]
+ then
+ watermark_scale=10
+ fi
+fi
# convert extra_free_kbytes to pages
page_size=$(getconf PAGESIZE)