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Yao Chen 337606cc8b Fix the stats log in lmkd 
1. let logs be written to statsd directly like all other stats logs.
   + stats log should not write to logd anymore(b/78239479)
2. fixed the log format
   + need to embed the elapsed real time in the log
3. fixed the log context reuse problem
   +reset the log context buffer and internal state before reuse

Bug: 78603347
Bug: 78239479

Test: tested with alloc_stress, and saw logs written to statsd

performance measurement (memory & cpu):
https://paste.googleplex.com/5508158646648832

Change-Id: I345f0eace8ba1687ff480fb88e9abba1d8533f76
 		2018-05-03 16:04:27 -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 Fix the stats log in lmkd 2018-05-03 16:04:27 -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 2018-04-17 01:42:06 +00:00
liblmkd_utils.c lmkd: Introduce liblmkd_utils for communicating with lmkd process 2018-01-31 18:10:49 +00:00
lmkd.c Fix the stats log in lmkd 2018-05-03 16:04:27 -07:00
lmkd.rc Enable hidepid=2 on /proc 2015-11-09 09:08:46 -08:00
statslog.c Fix the stats log in lmkd 2018-05-03 16:04:27 -07:00
statslog.h Fix the stats log in lmkd 2018-05-03 16:04:27 -07:00

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