History

Chih-Hung Hsieh 62b0ef556d Declare __fake_use_va_args as a variadic function. * New clang compiler requires variadic function to have at least one named parameter type. * Use ##__VA_ARGS__ to work with empty __VA_ARGS__. * Fix one ALOG_ASSERT parameter bug in lmkd/lmkd.c. Bug: 111614304 Test: make with WITH_TIDY=1 Change-Id: I90f35aa88527a6897954f69a35b256a157a725c5		2018-07-25 14:36:35 -07:00
..
include	lmkd: Introduce liblmkd_utils for communicating with lmkd process	2018-03-09 11:18:53 -08:00
tests	lmkd: test: access /sys/module/lowmemorykiller/ as u:r:shell:s0	2018-04-03 14:41:11 +00:00
Android.bp	lmkd: only mlockall() if enabled	2018-04-03 14:41:26 +00:00
liblmkd_utils.c	lmkd: Introduce liblmkd_utils for communicating with lmkd process	2018-03-09 11:18:53 -08:00
lmkd.c	Declare __fake_use_va_args as a variadic function.	2018-07-25 14:36:35 -07:00
lmkd.rc	lmkd: limit capability set to minimum	2018-04-16 14:51:56 -07:00
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	2018-04-15 16:02:36 +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