Commit cfd8864f authored Aug 24, 2022 by Suren Baghdasaryan

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: 642048d9 ("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

parent a5d944f6

init/extra_free_kbytes.sh

+13 −1

Original line number	Diff line number	Diff line
		@@ -77,7 +77,19 @@ then
		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)