History

Wei Wang 6f2198b33c lmkd: bump process priority and set to FOREGROUND group before kill This should help speed up reclaim memory. Bug: 118468011 Bug: 121439388 Test: run mem-pressure with lmkd Change-Id: Iae7aa35483eb0e8bbeccaa425559c6021c845ee1 Merged-In: Iae7aa35483eb0e8bbeccaa425559c6021c845ee1		2019-01-23 05:20:36 +00:00
..
include	lmkd: Implement pid purge command to clear old pids when zygote restarts	2018-10-10 22:11:23 +00:00
tests	lmkd: rate-limit and cleanup failed kill reports	2018-09-07 18:27:17 -07:00
Android.bp	Fix the stats log in lmkd	2018-05-03 16:04:27 -07:00
liblmkd_utils.c	lmkd: Introduce liblmkd_utils for communicating with lmkd process	2018-01-31 18:10:49 +00:00
lmkd.c	lmkd: bump process priority and set to FOREGROUND group before kill	2019-01-23 05:20:36 +00:00
lmkd.rc	Enable hidepid=2 on /proc	2015-11-09 09:08:46 -08:00
OWNERS	Add lmkd/OWNERS.	2017-12-08 16:12:58 -08:00
README.md	lmkd: Introduce support for legacy kill algorithm that uses minfree levels	2018-04-17 01:42:06 +00:00
statslog.c	Fix the stats log in lmkd	2018-05-03 16:04:27 -07:00
statslog.h	Read memory stats from /proc/pid/stat file.	2018-10-12 21:28:50 +00:00

README.md

Android Low Memory Killer Daemon

Introduction

Android Low Memory Killer Daemon (lmkd) is a process monitoring memory state of a running Android system and reacting to high memory pressure by killing the least essential process(es) to keep system performing at acceptable levels.

Background

Historically on Android systems memory monitoring and killing of non-essential processes was handled by a kernel lowmemorykiller driver. Since Linux Kernel 4.12 the lowmemorykiller driver has been removed and instead userspace lmkd daemon performs these tasks.

Android Properties

lmkd can be configured on a particular system using the following Android properties:

ro.config.low_ram: choose between low-memory vs high-performance device. Default = false.

ro.lmk.use_minfree_levels: use free memory and file cache thresholds for making decisions when to kill. This mode works the same way kernel lowmemorykiller driver used to work. Default = false

ro.lmk.low: min oom_adj score for processes eligible to be killed at low vmpressure level. Default = 1001 (disabled)

ro.lmk.medium: min oom_adj score for processes eligible to be killed at medium vmpressure level. Default = 800 (non-essential processes)

ro.lmk.critical: min oom_adj score for processes eligible to be killed at critical vmpressure level. Default = 0 (all processes)

ro.lmk.critical_upgrade: enables upgrade to critical level. Default = false

ro.lmk.upgrade_pressure: max mem_pressure at which level will be upgraded because system is swapping too much. Default = 100 (disabled)

ro.lmk.downgrade_pressure: min mem_pressure at which vmpressure event will be ignored because enough free memory is still available. Default = 100 (disabled)

ro.lmk.kill_heaviest_task: kill heaviest eligible task (best decision) vs. any eligible task (fast decision). Default = false

ro.lmk.kill_timeout_ms: duration in ms after a kill when no additional kill will be done, Default = 0 (disabled)

ro.lmk.debug: enable lmkd debug logs, Default = false