ef3650f8a0
After a memory event happens event handler can assess current memory condition and decide if and when lmkd should re-check memory metrics in order to respond to changing memory conditions. Change the event handler interface to allow control over polling period and ability to start/extend polling session. Bug: 132642304 Test: lmkd_unit_test Change-Id: Ia74011e943140b6cffbf452ff8e1744b7336eacf Signed-off-by: Suren Baghdasaryan <surenb@google.com> |
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| include | ||
| libpsi | ||
| tests | ||
| Android.bp | ||
| event.logtags | ||
| liblmkd_utils.c | ||
| lmkd.c | ||
| lmkd.rc | ||
| OWNERS | ||
| README.md | ||
| statslog.c | ||
| statslog.h | ||
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