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Suren Baghdasaryan 9dbd937b4c lmkd: Add lmkd README file 
Add README file providing lmkd overview and description for its
properties.

Bug: 77299493
Bug: 75322373
Change-Id: I30236dd4ccaa2b48c31dfb80b63f0b82b49b5744
Merged-In: I30236dd4ccaa2b48c31dfb80b63f0b82b49b5744
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
(cherry picked from commit 7e5dea82a5)
2018-04-16 09:26:40 -07:00
..
include lmkd: Introduce liblmkd_utils for communicating with lmkd process 2018-01-31 18:10:49 +00:00
tests lmkd: Implement lmkd-test 2018-01-31 18:11:38 +00:00
Android.bp Use usel_mkd_stats_log build variable while compiling lmkd with stats logging feature. 2018-03-23 20:33:57 +00:00
liblmkd_utils.c lmkd: Introduce liblmkd_utils for communicating with lmkd process 2018-01-31 18:10:49 +00:00
lmkd.c lmkd: Protect against buffer overflow 2018-03-27 21:59:31 +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: Add lmkd README file 2018-04-16 09:26:40 -07:00
statslog.c Functions to log stats log from LMKD. 2018-01-29 15:18:04 -08:00
statslog.h Fix compilation issue when LMKD_LOG_STATS is defined. 2018-03-26 18:15:25 +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.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