2018-04-13 20:36:46 +02:00
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Android Low Memory Killer Daemon
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Introduction
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------------
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Android Low Memory Killer Daemon (lmkd) is a process monitoring memory
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state of a running Android system and reacting to high memory pressure
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by killing the least essential process(es) to keep system performing
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at acceptable levels.
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Background
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----------
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Historically on Android systems memory monitoring and killing of
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non-essential processes was handled by a kernel lowmemorykiller driver.
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Since Linux Kernel 4.12 the lowmemorykiller driver has been removed and
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instead userspace lmkd daemon performs these tasks.
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Android Properties
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------------------
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lmkd can be configured on a particular system using the following Android
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properties:
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ro.config.low_ram: choose between low-memory vs high-performance
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device. Default = false.
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2018-04-13 22:53:43 +02:00
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ro.lmk.use_minfree_levels: use free memory and file cache thresholds for
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making decisions when to kill. This mode works
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the same way kernel lowmemorykiller driver used
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to work. Default = false
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2018-04-13 20:36:46 +02:00
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ro.lmk.low: min oom_adj score for processes eligible to be
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killed at low vmpressure level. Default = 1001
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(disabled)
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ro.lmk.medium: min oom_adj score for processes eligible to be
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killed at medium vmpressure level. Default = 800
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(non-essential processes)
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ro.lmk.critical: min oom_adj score for processes eligible to be
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killed at critical vmpressure level. Default = 0
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(all processes)
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ro.lmk.critical_upgrade: enables upgrade to critical level. Default = false
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ro.lmk.upgrade_pressure: max mem_pressure at which level will be upgraded
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because system is swapping too much. Default = 100
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(disabled)
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ro.lmk.downgrade_pressure: min mem_pressure at which vmpressure event will
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be ignored because enough free memory is still
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available. Default = 100 (disabled)
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ro.lmk.kill_heaviest_task: kill heaviest eligible task (best decision) vs.
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any eligible task (fast decision). Default = false
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ro.lmk.kill_timeout_ms: duration in ms after a kill when no additional
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kill will be done, Default = 0 (disabled)
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ro.lmk.debug: enable lmkd debug logs, Default = false
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